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 EPA Document #: EPA/600/R-14/442 

METHOD 530 DETERMINATION OF SELECT SEMIVOLATILE ORGANIC 

CHEMICALS IN DRINKING WATER BY SOLID PHASE 

EXTRACTION AND GAS CHROMATOGRAPHY/ MASS 

SPECTROMETRY (GC/MS) 

Version 1.0 

January, 2015 

Paul E. Grimmett 

NATIONAL EXPOSURE RESEARCH LABORATORY 

OFFICE OF RESEARCH AND DEVELOPMENT 

U. S. ENVIRONMENTAL PROTECTION AGENCY 

CINCINNATI, OHIO 45268 
 

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METHOD 530

DETERMINATION OF SELECT SEMIVOLATILE ORGANIC CHEMICALS IN 

DRINKING WATER BY SOLID PHASE EXTRACTION AND GAS 

CHROMATOGRAPHY/ MASS SPECTROMETRY (GC/MS)

1. SCOPE AND APPLICATION 

1.1. This is a gas chromatography/mass spectrometry (GC/MS) method for the 

determination of selected semivolatile organic compounds in drinking waters. 

Accuracy and precision data have been generated in reagent water, and in finished 

ground and surface waters for the compounds listed in the table below. This method 

was initially developed with full scan GC/MS, but performance has also been 

demonstrated in the selected ion monitoring (SIM) mode for all analytes. SIM is useful 

when enhanced sensitivity is desirable. An example chromatogram which includes the 

entire analyte list is shown in Fig. 1. 

Analyte

Chemical Abstract Services 

Registry Number (CASRN)

o-toluidine 95-53-4

quinoline 91-22-5

butylated hydroxyanisole (BHA) 25013-16-5

dimethipin 55290-64-7

1.2. The Minimum Reporting Level (MRL) is the lowest analyte concentration that meets 

Data Quality Objectives (DQOs) that are developed based on the intended use of this 

method. The single laboratory lowest concentration MRL (LCMRL) (Sect. 3.12) is 

the lowest true concentration for which the future recovery is predicted to fall, with 

high confidence (99 percent), between 50 and 150 percent recovery. The LCMRL is 

compound dependent and is also dependent on extraction efficiency, sample matrix, 

fortification concentration, and instrument performance. The procedure used to 

determine the LCMRL is described elsewhere.1,2 During method development, 

LCMRLs were determined from the results of laboratory fortified blanks (LFBs) in 

full scan mode and in the SIM mode for all method analytes. These LCMRLs are 

provided in Tables 5 and 9 for full scan and SIM modes, respectively. 

1.3. Laboratories using this method are not required to determine the LCMRL for this 

method, but will need to demonstrate that their laboratory MRL for this method 

meets the requirements described in Sect. 9.2.4. 
 

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1.4. Determining the Detection Limit (DL) for analytes in this method is optional 

(Sect. 9.2.6). Detection limit is defined as the statistically calculated minimum 

concentration that can be measured with 99% confidence that the reported value is 

greater than zero.3 The DL is compound dependent and is also dependent on 

extraction efficiency, sample matrix, fortification concentration, and instrument 

performance. DLs have been determined for all analytes in full scan mode (Table 5) 

and in SIM mode (Table 9).

1.5. This method is intended for use by analysts skilled in solid phase extractions, the 

operation of GC/MS instruments, and the interpretation of the associated data. 

1.6. METHOD FLEXIBILITY – In recognition of technological advances in analytical 

systems and techniques, the laboratory is permitted to modify the GC inlet, inlet 

conditions, column, injection parameters, and all other GC and MS conditions. 

Changes may not be made to sample collection and preservation (Sect. 8), sample 

extraction (Sect. 11) or to the Quality Control (QC) requirements (Sect. 9). Method 

modifications should be considered only to improve method performance. 

Modifications that are introduced in the interest of reducing cost or sample 

processing time, but result in poorer method performance, should not be used. In all 

cases where method modifications are proposed, the analyst must perform the 

procedures outlined in the initial demonstration of capability (IDC, Sect. 9.2), verify 

that all QC acceptance criteria in this method (Sect. 9) are met, and that method 

performance in real sample matrices is equivalent to that demonstrated for 

Laboratory Fortified Sample Matrices (LFSMs) in Sect. 17. 

 Note: The above method flexibility section is intended as an abbreviated summation 

of method flexibility. Sects. 4-12 provide detailed information of specific portions of 

the method that may be modified. If there is any perceived conflict between the 

general method flexibility statement in Sect. 1.6 and specific information in Sects.

4-12, Sects. 4-12 supersede Sect.1.6. 

2. SUMMARY OF METHOD 

2.1. A 1-liter water sample is fortified with surrogate analytes and passed through a solid 

phase extraction (SPE) device (Sects. 6.9-6.11) to extract the target analytes and 

surrogates. The compounds are eluted from the solid phase with a small amount of 

organic solvents. The solvent extract is dried by passing it through a column of 

anhydrous sodium sulfate, concentrated by evaporation with nitrogen gas, and then 

adjusted to a 1-mL volume with dichloromethane after adding the internal standards. 

A splitless injection is made into a GC equipped with a high-resolution fused silica 

capillary column that is interfaced to an MS. The analytes are separated and 

identified by comparing the acquired mass spectra and retention times to reference 

spectra and retention times for calibration standards acquired under identical GC/MS 

conditions. The GC/MS may be operated in the full scan, SIM, or selected ion 

storage (SIS) mode (Sects 3.19 and 3.20). The GC/MS may be calibrated using 

standards prepared in solvent or using matrix-matched standards (Sects. 3.15 and 
 

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7.2.4). The concentration of each analyte is calculated by using its integrated peak 

area and the internal standard technique. Surrogate analytes are added to all Field 

and Quality Control (QC) Samples to monitor the performance of each extraction 

and overall method performance. 

2.2 Butylated hydroxyanisole (BHA) can be affected by matrix induced chromatographic 

response enhancement (Sect. 3.14), when analyzed at low concentrations. Refer to 

Sect. 13 for information regarding method performance. 

3. DEFINITIONS 

3.1. ANALYSIS BATCH - A set of samples that is analyzed on the same instrument 

during a 24-hour period that begins and ends with the analysis of the appropriate 

Continuing Calibration Check (CCC) Standards. Additional CCCs may be required 

depending on the length of the analysis batch and/or the number of Field Samples. 

3.2. CALIBRATION STANDARD (CAL) - A solution prepared from the primary 

dilution standard solution or stock standard solution(s) and the internal standards and 

surrogate analytes. The CAL solutions are used to calibrate the instrument response 

with respect to analyte concentration. In this method, traditional CAL standards 

prepared in dichloromethane (DCM) may be used or matrix-matched standards (Sect. 

3.15) prepared in a concentrated laboratory reagent water (LRW) extract may be 

used. This procedure is described in Sect. 7.2.4.2. 

3.3. CONTINUING CALIBRATION CHECK (CCC) STANDARD - A calibration 

standard containing one or more method analytes, which is analyzed periodically to 

verify the accuracy of the existing calibration for those analytes. 

3.4. DETECTION LIMIT (DL) - The minimum concentration of an analyte that can be 

identified, measured and reported with 99% confidence that the analyte 

concentration is greater than zero. This is a statistical determination (Sect. 9.2.6), and 

accurate quantitation is not expected at this level.3

3.5. EXTRACTION BATCH - A set of up to 20 Field Samples (not including QC 

samples) extracted together by the same person(s) during a work day using the same 

lot of solid phase extraction devices, solvents, surrogate solution, and fortifying 

solutions. Required QC samples include Laboratory Reagent Blank, Laboratory 

Fortified Blank, Laboratory Fortified Sample Matrix, and either a Field Duplicate or 

Laboratory Fortified Sample Matrix Duplicate. 

3.6. FIELD DUPLICATES (FD1 and FD2) - Two separate samples collected at the same 

time and place under identical circumstances, and treated exactly the same 

throughout field and laboratory procedures. Analyses of FD1 and FD2 provide an 

estimate of the precision associated with sample collection, preservation, and 

storage, as well as with laboratory procedures. 
 

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3.7. INTERNAL STANDARD (IS) - A pure compound added to an extract or standard 

solution in a known amount and used to measure the relative responses of the 

method analytes and surrogates. 

3.8. LABORATORY FORTIFIED BLANK (LFB) - An aliquot of reagent water or other 

blank matrix to which known quantities of the method analytes and all the 

preservation compounds are added. The LFB is processed and analyzed exactly like 

a sample, and its purpose is to determine whether the methodology is in control, and 

whether the laboratory is capable of making accurate and precise measurements. 

3.9. LABORATORY FORTIFIED SAMPLE MATRIX (LFSM) - An aliquot of a Field 

Sample to which known quantities of the method analytes and all the preservation 

compounds are added. The LFSM is processed and analyzed exactly like a sample, 

and its purpose is to determine whether the sample matrix contributes bias to the 

analytical results. The background concentrations of the analytes in the sample 

matrix must be determined in a separate aliquot and the measured values in the 

LFSM corrected for background concentrations. 

3.10. LABORATORY FORTIFIED SAMPLE MATRIX DUPLICATE (LFSMD) - A 

duplicate Field Sample used to prepare the LFSM, which is fortified, extracted and 

analyzed identically to the LFSM. The LFSMD is used instead of the Field Duplicate 

to assess method precision and accuracy when the occurrence of a method analyte is 

infrequent. 

3.11. LABORATORY REAGENT BLANK (LRB) - An aliquot of reagent water that is 

treated exactly as a sample including exposure to all glassware, equipment, solvents, 

reagents, sample preservatives, internal standards, and surrogates that are used in the 

extraction batch. The LRB is used to determine if method analytes or other 

interferences are present in the laboratory environment, the reagents, or the 

extraction apparatus. 

3.12. LOWEST CONCENTRATION MINIMUM REPORTING LEVEL (LCMRL) - The 

single-laboratory LCMRL is the lowest true concentration for which the future 

recovery is predicted to fall, with high confidence (99 percent), between 50 and 150 

percent recovery.1,2

3.13. MATERIAL SAFETY DATA SHEET (MSDS) - Written information provided by 

vendors concerning a chemical’s toxicity, health hazards, physical properties, fire, 

and reactivity data including storage, spill, and handling precautions. 

3.14. MATRIX-INDUCED CHROMATOGRAPHIC RESPONSE ENHANCEMENT 

(MICRE) - This phenomenon occurs when, in the absence of matrix components, 

method analytes in calibration solutions are degraded or absorbed in the GC injector 

or column, resulting in poor peak shapes and low response. When subsequent sample 

extracts containing the analytes and components from a complex sample matrix are 

injected, peak shape and response improve. In this situation, quantitative data for 
 

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field samples may exhibit a high bias.4-11 Generally, overestimation of results is 

more pronounced at low analyte concentrations. 

3.15. MATRIX-MATCHED CALIBRATION STANDARD - A calibration standard that 

is prepared by adding method analytes to a concentrated extract of a matrix (reagent 

water is used for this method) that has been prepared following all the extraction and 

sample preparation steps of the analytical method. The material extracted from the 

matrix reduces matrix-induced response enhancement effects and improves the 

quantitative accuracy of sample results.10,11

3.16. MINIMUM REPORTING LEVEL (MRL) - The minimum concentration that can be 

reported by a laboratory as a quantitated value for a method analyte in a sample 

following analysis. This concentration must meet the criteria defined in Sect. 9.2.4

and must not be any lower than the concentration of the lowest continuing calibration 

check standard for that analyte. The MRL may be determined by the laboratory 

based upon project objectives, or may be set by a regulatory body as part of a 

compliance monitoring program. 

3.17. PRIMARY DILUTION STANDARD SOLUTION (PDS) - A solution containing 

method analytes, internal standards, or surrogate analytes prepared in the laboratory 

from stock standard solutions and diluted as needed to prepare calibration solutions 

and other analyte solutions. 

3.18. QUALITY CONTROL SAMPLE (QCS) - A solution prepared using a PDS of 

method analytes obtained from a source external to the laboratory and different from 

the source of calibration standards. The second source PDS and the surrogate PDS 

are used to fortify the QCS at a known concentration. The QCS is used to verify the 

accuracy of the primary calibration standards. 

3.19. SELECTED ION MONITORING (SIM) - An MS technique where only one or a 

few ions are monitored for each target analyte. When used with gas chromatography, 

the set of ions monitored is usually changed periodically throughout the 

chromatographic run, to correlate with the characteristic ions of the analytes, SURs 

and ISs as they elute from the chromatographic column. The technique is often used 

to increase sensitivity. Throughout this document, the term “SIM” will be used to 

include both SIM as described here and SIS as described in Sect. 3.20. 

3.20. SELECTED ION STORAGE (SIS) - An MS technique typically associated with ion 

trap mass spectrometers in which only one or a few ions are stored at any given time 

point. When used with gas chromatography, the set of ions stored is usually changed 

periodically throughout the chromatographic run, to correlate with the characteristic 

ions of the analytes, SURs and ISs as they elute from the chromatographic column. 

SIS can be used to enhance sensitivity. Throughout this document the term “SIM” 

will be used to include both SIM (Sect. 3.19) and SIS. 
 

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3.21. STOCK STANDARD SOLUTION (SSS) - A concentrated solution containing one 

or more method analytes prepared in the laboratory using assayed reference materials 

or purchased from a reputable commercial source. 

3.22. SURROGATE ANALYTE (SUR) - A pure analyte, which is extremely unlikely to 

be found in any sample, and which is added to a sample aliquot in a known amount 

before extraction or other processing, and is measured with the same procedures used 

to measure other sample components. The purpose of the SUR is to monitor method 

performance with each sample. In this method, the SURs are isotopically labeled 

analogues of selected method analytes. 

4. INTERFERENCES

4.1. All glassware must be meticulously cleaned. Wash glassware with detergent and tap 

water, rinse with tap water, followed by reagent water. Rinse with methanol and/or 

acetone. Non-volumetric glassware may be heated in a muffle furnace at 400 °C for 

two hours as a substitute for solvent rinsing. Volumetric glassware should not be 

heated in an oven above 120 °C. 

4.2. Method interferences may be caused by contaminants in solvents, reagents 

(including reagent water), sample bottles and caps, and other sample processing 

hardware that lead to discrete artifacts and/or elevated baselines in the chromatograms. All items such as these must be routinely demonstrated to be free from 

interferences (less than 1/3 the MRL for each target analyte) under the conditions of 

the analysis by analyzing laboratory reagent blanks as described in Sect. 9.3.1. 

Subtracting blank values from sample results is not permitted.

4.3. Matrix interferences may be caused by contaminants that are co-extracted from the 

sample. The extent of matrix interferences will vary considerably from source to 

source, depending upon the nature of the water. Water samples high in total organic 

carbon (TOC) may have elevated baselines or interfering peaks. Matrix components 

may directly interfere by producing a signal at or near the retention time of an 

analyte peak. They can also enhance the signal of method analytes (Sect. 3.14). 

Analyses of LFSMs are useful in identifying matrix interferences. 

4.4. Relatively large quantities of the buffer and preservatives (Sect. 8.1.2) are added to 

sample bottles. The potential exists for trace-level organic contaminants in these 

reagents. Interferences from these sources should be monitored by analysis of 

laboratory reagent blanks, particularly when new lots of reagents are acquired. 

4.5. Solid phase extraction media have been observed to be a source of interferences.12

The analysis of laboratory reagent blanks can provide important information 

regarding the presence or absence of such interferences. Brands and lots of solid 

phase extraction devices should be tested to ensure that contamination does not 

preclude analyte identification and quantitation. 
 

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4.6. Analyte carryover may occur when a relatively “clean” sample is analyzed 

immediately after a sample (or standard) that contains relatively high concentrations 

of compounds. Syringes and GC injection port liners must be cleaned carefully or 

replaced as needed. After analysis of a sample (or standard) that contains high 

concentrations of compounds, a laboratory reagent blank should be analyzed to 

ensure that accurate values are obtained for the next sample. 

4.7. Silicone compounds may be leached from punctured autosampler vial septa, 

particularly when particles of the septa are present in the vial for an extended time. 

This can occur after repeated injections from the same autosampler vial. These 

silicone compounds, which appear as regularly spaced chromatographic peaks with 

similar MS fragmentation patterns, can unnecessarily complicate the total ion 

chromatograms and may cause interferences at high levels. 

4.8. In cases where the SPE disks or cartridges are dried by pulling room air through the 

media using vacuum, it may be possible for the media to become contaminated by 

components in room air. This was not observed during method development, but if 

laboratories encounter contamination problems associated with room air, compressed 

gas cylinders of high purity nitrogen may be used for drying SPE media during 

sample processing. 

5. SAFETY

5.1. The toxicity or carcinogenicity of each reagent used in this method has not been 

precisely defined. Each chemical should be treated as a potential health hazard, and 

exposure to these chemicals should be minimized. Each laboratory is responsible for 

maintaining an awareness of OSHA regulations regarding safe handling of chemicals 

used in this method. A reference file of MSDSs should be made available to all 

personnel involved in the chemical analysis. Additional references to laboratory 

safety are available.13-15

5.2. Pure standard materials and stock standard solutions of these compounds should be 

handled with suitable protection to skin and eyes, and care should be taken not to 

breathe the vapors or ingest the materials. 

6. EQUIPMENT AND SUPPLIES 

References to specific brands or catalog numbers are included for illustration only, and do 

not imply endorsement of the product. Other brands of equivalent quality may be used. The 

SPE sorbents described in Sect. 6.9 are proprietary products that have been fully evaluated 

for use in this method. Due to their proprietary status, some chemistry aspects of the sorbents 

are unknown, making equivalency difficult to determine. The EPA document “Technical 

Notes on Drinking Water Methods”16 provides criteria for judging equivalency of SPE 

products (pg. 47). Before analyses are performed for compliance under the Safe Drinking 

Water Act, questions regarding equivalency of alternate sorbent materials must be addressed 

to the Office of Ground Water and Drinking Water Alternate Test Procedure Coordinator.17
 

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6.1. SAMPLE CONTAINERS - 1-L or 1-qt amber glass bottles fitted with 

polytetrafluoroethylene (PTFE)-lined screw caps are preferred. Clear glass bottles 

with PTFE-lined screw caps may be substituted if sample bottles are wrapped with 

foil, stored in boxes, or otherwise protected from light during sample shipping and 

storage. 

6.2. VIALS - Various sizes of amber glass vials with PTFE-lined screw caps for storing 

standard solutions and extracts. Amber glass 2-mL autosampler vials with PTFEfaced septa. 

6.3. VOLUMETRIC FLASKS - Class A, suggested sizes include 1, 5, and 10 mL for 

preparation of standards and dilution of extract to final volume. 

6.4. GRADUATED CYLINDERS - Suggested sizes include 5, 10, 250 and 1000 mL. 

6.5. MICRO SYRINGES - Suggested sizes include 10, 25, 50, 100, 250, 500, and 

1000 μL. 

6.6. DRYING COLUMN - The drying column must be able to contain 7-8 g of 

anhydrous sodium sulfate (Na2SO4). The drying column should not leach interfering 

compounds or irreversibly adsorb method analytes. Any small glass or 

polypropylene column may be used, such as Supelco #57176. 

6.7. COLLECTION TUBES - 15 mL, conical tubes (Fisher #05-569-3) or other 

glassware suitable for collection of the eluent from the solid phase sorbent after 

extraction and for collecting extract from drying tube. 

6.8. ANALYTICAL BALANCE - Capable of weighing to the nearest 0.0001 g. 

6.9. SPE APPARATUS USING SPE CARTRIDGES (6-mL COLUMNS); MANUAL 

EXTRACTION 

6.9.1. SPE CARTRIDGES - Modified DVB or PS/DVB polymer 

6.9.1.1. Waters Oasis HLB, 500 mg (Waters #186000115) – 

divinylbenzene N-vinylpyrrolidone copolymer 

6.9.1.2. Phenomenex Strata-X, 500 mg (Phenomenex #8B-S100-HCH) –

polystyrene divinylbenzene N-vinylpyrrolidone copolymer 

6.9.1.3. Agilent Mega Bond Elut Plexa, 500 mg (Agilent #12259506) –

hydrophilic polystyrene divinylbenzene polymer 
 

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6.9.2. VACUUM EXTRACTION MANIFOLD - Equipped with flow/vacuum 

control (Supelco #57030-U or equivalent). 

6.9.3. SAMPLE DELIVERY SYSTEM - Use of a transfer tube system (Supelco 

“Visiprep”, #57275 or equivalent), which transfers the sample directly from 

the sample container to the SPE cartridge is recommended. 

6.9.4. An automatic or robotic system designed for use with SPE cartridges may 

be used if all quality control requirements discussed in Sect. 9 are met. 

Automated systems may use either vacuum or positive pressure to process 

samples and solvents through the cartridge. All sorbent washing, 

conditioning, sample loading, rinsing, drying and elution steps must be 

performed as closely as possible to the manual procedure. The solvents used 

for washing, conditioning, and sample elution must be the same as those 

used in the manual procedure; however, the amount used may be increased 

as necessary to achieve the required data quality. Solvent amounts may not 

be decreased. Sorbent drying times prior to elution may be modified to 

achieve the required data quality. Caution should be exercised when 

increasing solvent volumes. Increased extract volume will likely necessitate 

the need for additional sodium sulfate drying, and extended evaporation 

times which may compromise data quality. Caution should also be 

exercised when modifying sorbent drying times. Excessive drying may 

cause losses due to analyte volatility, and excessive contact with room air 

may oxidize some method analytes. Insufficient drying may leave excessive 

water trapped in the disk and lead to poor recoveries. 

6.10. EXTRACT CONCENTRATION SYSTEM - Extracts are concentrated by 

evaporation with nitrogen gas using a water bath set at 40 °C (N-Evap, Model 11155, 

Organomation Associates, Inc., or equivalent). 

6.11. LABORATORY OR ASPIRATOR VACUUM SYSTEM - Sufficient capacity to 

maintain a vacuum of approximately 15 to 25 inches of mercury. 

6.12. GAS CHROMATOGRAPH/MASS SPECTROMETER (GC/MS) SYSTEM 

6.12.1. FUSED SILICA CAPILLARY GC COLUMN - 30 m x 0.25-mm inside 

diameter (i.d.) fused silica capillary column coated with a 0.25 μm bonded 

film of cyanopropyl phenyl and dimethylpolysiloxane (Restek Rtx-1701 or 

equivalent). Any capillary column that provides adequate capacity, 

resolution, accuracy, and precision may be used. A mid-polar, low-bleed 

column is recommended for use with this method to provide adequate 

resolution and minimize column bleed. 

6.12.2. GC INJECTOR AND OVEN - Some of the target compounds included in 

this method are subject to thermal breakdown in the GC injection port. This 

problem is exacerbated when the injector and/or the injection port liner is 
 

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not properly deactivated or is operated at excessive temperatures. The 

injection system must not allow analytes to contact hot stainless steel or 

other metal surfaces that promote decomposition. The performance data in 

Sect. 17 were obtained using hot, splitless injection using a 4 or 5-mm i.d. 

glass deactivated liner. Other injection techniques such as temperature 

programmed injections, cold on-column injections and large volume 

injections may be used if the QC criteria in Sect. 9 are met. Equipment 

designed appropriately for these alternate types of injections must be used if 

these options are employed.

6.12.3. GC/MS INTERFACE - The interface should allow the capillary column or 

transfer line exit to be placed within a few millimeters of the ion source. 

Other interfaces are acceptable as long as the system has adequate 

sensitivity and QC performance criteria are met. 

6.12.4. MASS SPECTROMETER (MS) - Any type of MS may be used (i.e., 

quadrupole, ion trap, time of flight, etc.) with electron ionization. The 

instrument may be operated in full scan mode or in SIM mode for enhanced 

sensitivity. The minimum scan range capability of the MS must be 45 to 

450 m/z, and it must produce a full scan mass spectrum that meets all 

criteria in Table 2 when a solution containing 5 ng (or less) of 

decafluorotriphenylphosphine (DFTPP) is injected into the GC/MS 

(Sect. 10.2.1).

6.12.5. DATA SYSTEM - An interfaced data system is required to acquire, store, 

and output MS data. The computer software should have the capability of 

processing stored GC/MS data by recognizing a GC peak within a given 

retention time window. The software must allow integration of the ion 

abundance of any specific ion between specified time or scan number 

limits. The software must be able to construct linear regressions and

quadratic calibration curves, and calculate analyte concentrations. 

7. REAGENTS AND STANDARDS SUPPLIES (References to specific brands or catalog 

numbers are included for illustration only, and do not imply endorsement of the product.) 

7.1. REAGENTS AND SOLVENTS - Reagent grade or better chemicals should be used 

in all tests. Unless otherwise indicated, it is intended that all reagents will conform to 

the specifications of the Committee on Analytical Reagents of the American 

Chemical Society (ACS), where such specifications are available. Other grades may 

be used, if the reagents are demonstrated free of analytes and interferences, and all 

method requirements in the Initial Demonstration of Capability (IDC) are met. 

7.1.1. HELIUM - 99.999 % or better, GC carrier gas. Alternate carrier gases, such as 

hydrogen (99.999 % or better) may be used if the QC criteria in Sect. 9 are 

met. Instrument manufacturers should be consulted prior to any GC carrier gas 

conversion. 
 

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7.1.2. LABORATORY REAGENT WATER (LRW) - Purified water which does 

not contain any measurable quantities of any target analytes or interfering 

compounds at or above 1/3 the MRL for each compound of interest. 

7.1.3. METHANOL (MeOH) (CASRN 67-56-1) - High purity, demonstrated to be 

free of analytes and interferences (Fisher Optima or equivalent). 

7.1.4. DICHLOROMETHANE (DCM) (CASRN 75-09-02) - High purity, 

demonstrated to be free of analytes and interferences (Fisher GC Resolv or 

equivalent). 

7.1.5. ACETONE (CASRN 67-64-1) - High purity, demonstrated to be free of 

analytes and interferences (Tedia Absolv or equivalent). 

7.1.6. SODIUM SULFATE (Na2SO4), ANHYDROUS (CASRN 7757-82-6) - 

Soxhlet extracted with DCM for a minimum of four hours or heated to 

400 °C for two hours in a muffle furnace. An “ACS grade, suitable for 

pesticide residue analysis,” is recommended. 

7.1.7. SAMPLE PRESERVATION REAGENTS – The following preservatives 

are solids at room temperature and may be added to the sample bottle before 

shipment to the field. 

7.1.7.1. BUFFER SALT MIX, pH 7 – The sample must be buffered to 

pH 7 with two components: 1) tris(hydroxymethyl)aminomethane, 

also called Tris, 0.47 g (CASRN 77-86-1, ACS Reagent Grade or 

equivalent); and 2) tris(hydroxymethyl)aminomethane 

hydrochloride, also called Tris HCl, 7.28 g (CASRN 1185-53-1, 

ACS Reagent Grade or equivalent). Alternately, 7.75 g of a 

commercial buffer crystal mixture, that is blended in proportion to 

the amounts given above (Sigma-Aldrich #T7193 or equivalent), 

can be used.

7.1.7.2. L-ASCORBIC ACID (CASRN 50-81-7) - Ascorbic acid reduces 

free chlorine at the time of sample collection (ACS Reagent Grade 

or equivalent). 

7.1.7.3. ETHYLENEDIAMINE TETRAACETIC ACID (EDTA), 

TRISODIUM SALT (CASRN 10378-22-0) - Trisodium EDTA is 

added to inhibit metal-catalyzed hydrolysis of analytes. 

7.1.7.4. DIAZOLIDINYL UREA (DZU) (CAS# 78491-02-8) – DZU is 

added to inhibit microbial growth. 
 

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7.2. STANDARD SOLUTIONS - Standard solutions of internal standards, surrogates 

and method analytes may be prepared gravimetrically or from commercially 

available stock solutions. When a compound purity is assayed to be 96% or greater, 

the weight can be used without correction to calculate the concentration of a 

gravimetrically prepared stock standard. Solution concentrations listed in this section 

were those used to develop this method and are included as an example only. 

Solution preparation steps may be modified as needed to meet the needs of the 

laboratory. Often, standard mixes appropriate to the method become commercially 

available subsequent to method publication. Even though stability times for 

standard solutions are suggested in the following sections, laboratories should 

use standard QC practices to determine when their standards need to be 

replaced. In addition, signs of evaporation and/or discoloration are indicators 

that a standard should be replaced. 

7.2.1. INTERNAL STANDARD (IS) SOLUTIONS - This method uses two IS 

compounds listed in the table below. A commercial mixture of ISs was used 

for method development, and it is highly recommended that other analysts 

use a commercial mix as well. However, if an analyst chooses to prepare a 

gravimetric stock solution, it should be prepared in acetone using a 

procedure similar to the preparation of analyte stocks as outlined in Sect. 

7.2.3.1. The PDS mix for ISs has been shown to be stable for at least one 

year when stored in amber glass screw cap vials at -5 °C or less. Using 

10 μL of the IS to fortify the final 1-mL extracts (Sect. 11.5) will yield a 

concentration of 5 μg/mL each for ISs for full scan analysis. Lower 

concentrations of ISs should be used for SIM analysis. For SIM analysis 

during method development, ISs were added to extracts such that their final 

concentration was 500 ng/mL. 

Note: Stock standard solutions and PDSs should be brought to room 

temperature and sonicated for a few minutes prior to use. This ensures that 

components are dissolved and the solution is homogeneous. 

Internal Standards CASRN Solvent PDS conc.

acenaphthene-d10 (IS 1) 15067-26-2 acetone 500 μg/mL

phenanthrene-d10 (IS 2) 1517-22-2 acetone 500 μg/mL

7.2.2. SURROGATE ANALYTE STANDARD SOLUTIONS - The surrogate 

analytes used in this method are listed in the table below. All SUR PDSs 

were used at the same concentration and were prepared in methanol. The 

SURs may be prepared from neat material or purchased (if available from 

commercial suppliers) as individual PDSs or a single PDS. For method 

development, neat material was purchased from CDN Isotopes 

(o-toluidine-d9, #D-3571) and Cambridge Isotopes (quinoline-d7, 

#DLM-1158-0.1). The SUR PDSs have been shown to be stable for at least 
 

530-14 

one year when stored in amber glass screw cap vials at -5 oC or less. For full 

scan analysis, 10 μL of each of these solutions was added to each 1L 

aqueous QC and Field Sample prior to extraction, for an expected final 

extract concentration of 5 μg/L of each SUR. For SIM analysis, the QC and 

Field Samples were fortified such that the expected final extract 

concentration was 500 ng/L for each SUR. 

 

Surrogates CASRN Solvent PDS conc.

o-toluidine-d9 (SUR 1) 194423-47-7 methanol 500 μg/mL

quinoline-d7 (SUR 2) 34071-94-8 methanol 500 μg/mL

 Notes: 

 Stock standard solutions and PDSs should be brought to room 

temperature and sonicated for a few minutes prior to use. This ensures 

that components are dissolved and the solution is homogeneous. 

 Stock standard solutions that will be used for aqueous sample 

fortification generally should be prepared at a concentration such that 

only a small volume (e.g., 5-100 μL) needs to be added to achieve the 

desired final concentration. This will minimize the quantity of organic 

solvent added to aqueous samples. 

7.2.3. ANALYTE STOCK SOLUTIONS 

7.2.3.1. ANALYTE STOCK STANDARD SOLUTIONS (SSS) 

(5.0 mg/mL) - Analyte standards may be purchased commercially 

as ampulized solutions prepared from neat materials. 

Commercially prepared SSSs are widely available for most method 

analytes. To prepare gravimetric stock standard solutions, add 

10 mg (weighed on analytical balance to 0.1 mg) of the pure 

material to 1.9 mL of methanol in a 2-mL volumetric flask, dilute 

to the mark, and transfer the solution to an amber glass vial. If the 

neat material is only available in quantities less than 10 mg, reduce 

the volume of solvent accordingly. If compound purity is 

confirmed by the supplier to be ≥ 96%, the weighed amount can be 

used without correction to calculate the concentration of the 

solution. Store at 4 oC or less to guard against degradation and 

evaporation. 

 Note: Stock standard solutions and PDSs should be brought to 

room temperature and sonicated for a few minutes prior to use. 

This ensures that components are dissolved and the solution is 

homogeneous. 
 

530-15 

7.2.3.2. ANALYTE PRIMARY DILUTION STANDARD (100 μg/mL) - 

Prepare the 100-μg/mL Analyte PDS by volumetric dilution of the 

Analyte Stock Standard Solutions (Sect. 7.2.3.1) in methanol to 

make a 100-μg/mL solution. The PDS can be used to fortify the 

LFBs and LFSMs with method analytes and to prepare calibration 

solutions. Care should be taken during storage to prevent 

evaporation. The Analyte PDS Solutions used during method 

development were stable for 6 months stored in an amber glass 

screw cap vials at -5 °C or less. 

Notes:

 Two separate Analyte PDS mixtures should be prepared: one 

PDS for o-toluidine and quinoline, and one PDS for BHA and 

dimethipin. Method development work exhibited degradation 

of o-toluidine in PDS mixtures with multiple analytes at high 

concentrations. 

 Fortification generally should be prepared at a concentration 

such that only a small volume (e.g., 5-100 μL) needs to be 

added to achieve the desired final concentration. This will 

minimize the quantity of organic solvent added to aqueous 

samples. 

 Stock standard solutions and PDSs should be brought to room 

temperature and sonicated for a few minutes prior to use. This 

ensures that components are dissolved and the solution is 

homogeneous. 

7.2.4. CALIBRATION SOLUTIONS - Calibration standards may be prepared in 

DCM or as matrix-matched calibration standards (Sect. 3.15). This option is 

provided so that the analyst has the flexibility to prepare calibration curves 

that will be appropriate for the various types of analytes and the calibration 

range of interest. If the analyses to be performed include only those analytes 

that are not susceptible to matrix induced response enhancement, and/or the 

concentrations to be measured are relatively high (e.g., ≥ 5μg/L), it is likely 

that accurate data can be obtained with the use of traditional CAL standards 

prepared in DCM. If low concentrations of analytes susceptible to matrix 

induced response enhancement need to be measured, it is likely that matrixmatched standards will be required to obtain accurate quantitative data. 

Whichever type of CAL solutions are selected, those CAL solutions should 

be used for all calibration and QC procedures described in the method. 

Note: Analytes observed to be susceptible to matrix induced response 

enhancement during method development are indicated in the “comments” 

portion of Table 1. However, the occurrence and degree of enhancement 

will depend upon the GC injector design, and the history of the injector, 

injector liner and GC column. It is highly recommended that prior to the 

initial demonstration of capability, separate calibration curves be generated 
 

530-16 

using DCM CALs and matrix-matched CALs for each analyte to be 

measured. A careful evaluation of the relative peak areas using each type of 

CAL, especially low concentration CALs, can serve as a guide to the 

possible occurrence and extent of matrix enhancement, and thus an 

indicator of which type of standards should be used.

7.2.4.1. CALIBRATION SOLUTIONS PREPARED IN SOLVENT - 

Prepare a series of six concentrations of calibration solutions in 

DCM, which contain the analytes of interest. The suggested 

concentrations in this paragraph are a description of the 

concentrations used during method development, and may be 

modified to conform with instrument sensitivity. For full scan 

analyses, concentrations ranging from 0.10-5.0 ng/μL are 

suggested for each analyte, with IS and SUR concentrations as 

described in Sect. 7.2.1 and 7.2.2. For SIM analysis, six 

concentrations in the range of 0.005-0.5 ng/μL are suggested, with 

reduced concentrations of the ISs and SURs (Sect. 7.2.1 and 7.2.2). 

The six CAL standards (CAL1 through CAL6) are prepared by 

combining appropriate aliquots of the Analyte PDS solution (Sect. 

7.2.3.2) and the IS and SUR PDSs (Sects. 7.2.1. and 7.2.2). All 

calibration solutions should contain at least 60% DCM to avoid gas 

chromatographic anomalies such as poor peak shape, split peaks, 

etc. During method development, all analytes were prepared in a 

single set of calibration solutions. Calibration solutions were stable 

for six months when stored at -5 oC in amber screw top vials. 

7.2.4.2. MATRIX-MATCHED CALIBRATION SOLUTIONS - Prepare a 

series of six calibration solutions in the same manner as in Sect. 

7.2.4.1, but instead of preparation in DCM, calibration solutions 

are prepared in final solvent extracts derived from laboratory 

reagent water. One-liter aliquots of reagent water with sample 

preservatives added, are extracted using the sorbent selected for 

sample analysis, dried with sodium sulfate, and evaporated to 

<1 mL following the same procedure used for samples (Sects. 

11.3-11.5). However, the ISs, SURs, and analyte PDSs are 

added to the extract at appropriate concentrations 

immediately before the adjustment of the extract to 1 mL, i.e.,

they are not extracted. 

7.2.5. GC/MS TUNE CHECK SOLUTION (5 μg/mL or less) 

(CASRN 5074-71-5) - Prepare a DFTPP solution in DCM. Store this 

solution in an amber glass screw cap vial at 4 °C or less.
 

530-17 

8. SAMPLE COLLECTION, PRESERVATION, AND STORAGE

8.1. SAMPLE BOTTLE PREPARATION 

8.1.1. Grab samples must be collected using 1-liter or 1-quart sample bottles that 

meet the requirements in Sect. 6.1. 

8.1.2. Preservation reagents, listed in the table below, are added to each sample 

bottle as dry solids prior to shipment to the field (or prior to sample 

collection). 

Compound Amount Purpose

L-Ascorbic acid 0.10 g/L Dechlorination

Ethylenediaminetetraacetic acid, trisodium 

salt

0.35 g/L Inhibit metal-catalyzed 

hydrolysis of targets

Diazolidinyl Urea 1.0 g/L Microbial inhibitor

*Tris(hydroxymethyl)aminomethane 0.47 g/L First component of pH 7

buffer mixture

*Tris(hydroxymethyl)aminomethane

hydrochloride

7.28 g/L Second component of pH

7 buffer mixture

*Alternately, 7.75 g of a commercial buffer crystal mixture, that is blended in 

the proportions given in the table, can be used (Sect. 7.1.7.1). 

8.1.2.1. Residual chlorine must be reduced at the time of sample collection 

with 100 mg of ascorbic acid per liter. 

8.1.2.2. Trisodium EDTA must be added to inhibit potential metalcatalyzed hydrolysis of method analytes. 

8.1.2.3. Diazolidinyl urea (1.0 g) is added to inhibit microbial degradation 

of analytes.

8.1.2.4. The sample must be buffered to pH 7 to reduce the acid and base 

catalyzed hydrolysis of target analytes. The pH buffer has two 

components: tris(hydroxymethyl)aminomethane (0.47 g) and 

tris(hydroxymethyl)aminomethane hydrochloride (7.28 g). A 

commercially prepared combination of these two compounds can 

be purchased as pre-mixed crystals. When using the pH 7 

pre-mixed crystals, add 7.75 g per liter of water sample. 
 

530-18 

8.2. SAMPLE COLLECTION 

8.2.1. Open the tap and allow the system to flush until the water temperature has 

stabilized (usually 3-5 min). Collect samples from the flowing system. 

8.2.2. Fill sample bottles, taking care not to flush out the sample preservation 

reagents. Samples do not need to be collected headspace free. 

8.2.3. After collecting the sample, cap the bottle and agitate by hand until 

preservatives are dissolved. Immediately place in ice or refrigerate. 

8.3. SHIPMENT AND STORAGE - Samples must be chilled during shipment and must 

not exceed 10 °C during the first 48 hours after collection. Sample temperature must 

be confirmed to be at or below 10 °C when they are received at the laboratory, with 

the following exception. Samples arriving at the laboratory on the day of sampling 

may not have had time to achieve a temperature of less than 10 °C. This is acceptable 

as long as the cooling process has begun. Samples stored in the lab must be held at or 

below 6 °C until extraction, but should not be frozen. Sample holding time data are 

discussed in Sect. 13.3.

Note: Samples that are significantly above 10 oC at the time of collection, may need 

to be iced or refrigerated for a period of time, in order to chill them prior to shipping. 

This will allow them to be shipped with sufficient ice to meet the above 

requirements. 

8.4. SAMPLE AND EXTRACT HOLDING TIMES - Water samples should be extracted 

as soon as possible after collection but must be extracted within 14 days of 

collection. All extracts must be stored at -5 °C or less, protected from light and 

analyzed within 14 days after extraction (Sect. 13.4).

9. QUALITY CONTROL 

9.1. QC requirements include the Initial Demonstration of Capability (IDC) and ongoing 

QC requirements that must be met when preparing and analyzing Field Samples. 

This section describes QC parameters, their required frequency, and the performance 

criteria that must be met in order to meet EPA quality objectives. The QC criteria 

discussed in the following sections are summarized in Tables 10 and 11. These QC 

requirements are considered the minimum acceptable QC criteria. Laboratories are 

encouraged to institute additional QC practices to meet their specific needs. 

9.2. INITIAL DEMONSTRATION OF CAPABILITY - The IDC must be successfully 

performed prior to analyzing any Field Samples. Prior to conducting the IDC, the 

analyst must first generate an acceptable Initial Calibration following the procedure 
 

530-19 

outlined in Sect. 10.2. The IDC must be repeated if the laboratory changes the 

type or brand of SPE sorbent being used.

9.2.1. INITIAL DEMONSTRATION OF LOW SYSTEM BACKGROUND - 

Any time a new lot of SPE cartridges or disks is used, it must be 

demonstrated that a Laboratory Reagent Blank is reasonably free of 

contamination and that the criteria in Sect. 9.3.1 are met. 

9.2.2. INITIAL DEMONSTRATION OF PRECISION (IDP) - Prepare, extract, 

and analyze four to seven replicate LFBs fortified near the midrange of the 

initial calibration curve according to the procedure described in Sect. 11. 

Sample preservatives as described in Sect. 8.1.2 must be added to these 

samples. The relative standard deviation (RSD) of the results of the 

replicate analyses must be ≤ 20%.

9.2.3. INITIAL DEMONSTRATION OF ACCURACY - Using the same set of 

replicate data generated for Sect. 9.2.2, calculate average recovery. The 

average recovery expressed as the mean of the replicate values must be 

within 70-130 % of the true value for all analytes except o-toluidine, which 

must be within 50-130% of the true value. 

9.2.4. MINIMUM REPORTING LEVEL (MRL) CONFIRMATION - Establish a 

target concentration for the MRL based on the intended use of the method. 

The MRL may be established by a laboratory for their specific purpose or 

may be set by a regulatory agency. Establish an Initial Calibration following 

the procedure outlined in Sect. 10.2. The lowest calibration standard used to 

establish the Initial Calibration (as well as the low-level Continuing 

Calibration Check standard) must be at or below the concentration of the 

MRL. Establishing the MRL concentration too low may cause repeated 

failure of ongoing QC requirements. Confirm the MRL following the 

procedure outlined below. 

9.2.4.1. Fortify, extract, and analyze seven replicate Laboratory Fortified 

Blanks (LFBs) at the proposed MRL concentration. These LFBs 

must contain all method preservatives described in Sect. 8.1.2. 

Calculate the mean and standard deviation for these replicates. 

Determine the Half Range for the Prediction Interval of Results 

(HRPIR) using the equation below 

 

HRPIR 3.963S

 where: 

S = the standard deviation, and 3.963 is a constant value for seven 

replicates.1 
 

530-20 

9.2.4.2. Confirm that the upper and lower limits for the Prediction Interval 

of Result (PIR = Mean + HRPIR) meet the upper and lower 

recovery limits as shown below: 

 The Upper PIR Limit must be ≤150 percent recovery. 

 100  % 150% 

Fortified Concentration

Mean HRPIR

 

 The Lower PIR Limit must be ≥ 50 percent recovery. 

 100 %  50% 

Fortified Concentration

Mean HRPIR

9.2.4.3. The MRL is validated if both the Upper and Lower PIR Limits 

meet the criteria described above (Sect. 9.2.4.2). If these criteria 

are not met, the MRL has been set too low by the laboratory and 

must be demonstrated again at a higher concentration. If a required 

MRL set by a regulatory body has not been met, the analyst should 

evaluate possible problems in the execution of the extraction steps, 

and/or possible problems with instrument sensitivity. Reattempt 

MRL validation at the required MRL after problems have been 

addressed. 

9.2.4.4. Confirmation of the MRL Using Fortified Matrix Samples 

(optional)- This validation procedure may be used in addition to 

the reagent water confirmation described above. It may be useful 

in assessing any matrix induced quantitative bias at the MRL.

Obtain replicate 1 L aliquots of a water sample similar in nature to 

the ones planned for analysis. If tap waters from both ground and 

surface water sources are to be analyzed, it is recommended that a 

surface water sample be selected for verification. Analyze one 

aliquot using the procedures in this method to verify the absence of 

analytes of interest. Fortify seven remaining aliquots with the 

analytes to be measured near the expected MRL, and verify the 

MRL as described in Sects. 9.2.4.1 through 9.2.4.3. 

9.2.5. CALIBRATION CONFIRMATION - Analyze a Quality Control Sample as 

described in Sect. 9.3.9 to confirm the accuracy of the standards/calibration 

curve. 

9.2.6. DETECTION LIMIT DETERMINATION (optional) - While DL 

determination is not a specific requirement of this method, it may be 

required by various regulatory bodies associated with compliance 
 

530-21 

monitoring. It is the responsibility of the laboratory to determine if DL 

determination is required based upon the intended use of the data.

 Replicate analyses for this procedure should be done over at least three days 

(both the sample extraction and the GC analyses should be done over at 

least three days). Prepare at least seven replicate LFBs at a concentration 

estimated to be near the DL. This concentration may be estimated by 

selecting a concentration at 2-5 times the noise level. The DLs in Tables 5

and 9 were calculated from LFBs fortified at various concentrations as 

indicated in the table. The appropriate fortification concentrations will be 

dependent upon the sensitivity of the GC/MS system used. All preservation 

reagents listed in Sect. 8.1.2 must also be added to these samples. Analyze 

the seven (or more) replicates through all steps of Sects. 11 and 12. 

Note: If an MRL confirmation data set meets these requirements, a DL may 

be calculated from the MRL confirmation data, and no additional analyses 

are necessary. 

 Calculate the DL using the following equation: 

 

 

 .01 ,1( 99)



n 

DL ts

 

 where: 

 t (n-1, 1-α=0.99) = Student's t value for the 99% confidence level with n-1 

 degrees of freedom 

 n = number of replicates 

 s = standard deviation of replicate analyses. 

 Note: Do not subtract blank values when performing DL calculations. 

9.3. ONGOING QC REQUIREMENTS - This section summarizes the ongoing QC 

criteria that must be followed when processing and analyzing Field Samples. 

9.3.1. LABORATORY REAGENT BLANK (LRB) - An LRB is required with 

each extraction batch of up to 20 Field Samples to confirm that potential 

background contaminants are not interfering with the identification or 

quantitation of target analytes. If the LRB produces a peak within the 

retention time window of any analyte that would prevent the determination 

of that analyte, locate the source of contamination and eliminate the 

interference before processing samples. Background contamination must be 

reduced to an acceptable level before proceeding. Background from method 

analytes or other contaminants that interfere with the measurement of 

method analytes must be at or below 1/3 of the MRL. Blank contamination 

may be estimated by extrapolation, if the concentration is below the lowest 

calibration standard. Although this procedure is not allowed for sample 
 

530-22 

results as it may not meet data quality objectives, it can be useful in 

estimating background concentrations. If any of the method analytes are 

detected in the LRB at concentrations greater than 1/3 of the MRL, then all 

data for the problem analyte(s) must be considered invalid for all samples in 

the extraction batch. 

Note: It is extremely important to evaluate background values of analytes 

that commonly occur in LRBs. The MRL must be set at a value greater than 

three times the mean concentration observed in replicate LRBs. If LRB 

values are highly variable, setting the MRL to a value greater than the mean 

LRB concentration plus three times the standard deviation may provide a 

more realistic MRL. 

9.3.2. CONTINUING CALIBRATION CHECK (CCC) - CCC Standards are 

analyzed at the beginning of each analysis batch, after every ten Field 

Samples, and at the end of the analysis batch. See Sect. 10.3 for 

concentration requirements and acceptance criteria. 

9.3.3. LABORATORY FORTIFIED BLANK (LFB) - An LFB is required with 

each extraction batch of up to 20 Field Samples. The fortified concentration 

of the LFB must be rotated between low, medium, and high concentrations 

from batch to batch. The low concentration LFB must be as near as 

practical to, but no more than two times the MRL. Similarly, the high 

concentration LFB should be near the high end of the calibration range 

established during the initial calibration (Sect. 10.2). Results of the lowlevel LFB analyses must be 50-150% of the true value. Results of the 

medium and high-level LFB analyses must be 70-130% of the true value for 

all analytes except o-toluidine, which may be between 50-130% of the true 

value. If the LFB results do not meet these criteria for target analytes, then 

all data for the problem analyte(s) must be considered invalid for all samples in the extraction batch. 

9.3.4. MS TUNE CHECK - A complete description of the MS Tune Check is 

found in Sect. 10.2.1. The acceptance criteria for the MS Tune Check are 

summarized in Table 2. The MS Tune Check must be performed each time 

a major change is made to the mass spectrometer, and prior to establishing 

and/or re-establishing an initial calibration (Sect. 10.2). Daily DFTPP 

analysis is not required. 

 Note: The tune check is performed in full scan mode, even if samples will 

be analyzed in SIM mode. 

9.3.5. INTERNAL STANDARDS (IS) - The analyst must monitor the peak areas 

of the ISs in all injections during each analysis day. The peak area for each 

IS in any chromatographic run must not deviate by more than ±50% from 

the mean response in the CAL solutions analyzed for the initial analyte 
 

530-23 

calibration. In addition, the peak areas of ISs must not deviate by more than 

± 30% from the most recent CCC. If the IS areas in a chromatographic run 

do not meet these criteria, inject a second aliquot of that standard or extract. 

9.3.5.1. If the reinjected aliquot produces acceptable internal standard 

responses, report results for that aliquot. 

9.3.5.2. If the reinjected aliquot is a sample extract and fails again, the 

analyst should check the calibration by evaluating the CCCs within 

the analysis batch. If the CCCs are acceptable, extraction of the 

sample may need to be repeated provided the sample is still 

available and within the holding time. Otherwise, report results 

obtained from the reinjected extract, but annotate as “suspect/IS 

area.” Alternatively, collect a new sample and reanalyze. 

9.3.5.3. If the reinjected aliquot is a CAL standard, take remedial action 

(Sect. 10.3.3).

9.3.6. SURROGATE RECOVERY - Surrogate standards are fortified into the 

aqueous portion of all samples, LRBs, LFBs, CCCs, LFSMs, and LFSMDs 

prior to extraction. They are also added to the calibration standards. The 

surrogates are a means of assessing method performance from extraction to 

final chromatographic measurement. Calculate the recovery (%R) for each 

surrogate using the equation 

 % 100 











B

A

R

where: 

A = measured surrogate concentration for the QC or Field Sample, and 

B = fortified concentration of the surrogate. 

9.3.6.1. Surrogate recovery must be within 70-130% of the true value for 

quinoline-d7 and within 50-130% for o-toluidine-d9. When 

surrogate recovery from a sample, blank, or CCC is outside the 

acceptable range, check 1) calculations to locate possible errors, 2) 

the integrity of the surrogate analyte solution, 3) contamination, 

and 4) instrument calibration. Correct the problem and reanalyze 

the extract. 

9.3.6.2. If the extract reanalysis meets the surrogate recovery criterion, 

report only data for the reanalyzed extract. 

9.3.6.3. If the extract reanalysis fails the recovery criterion, the analyst 

should check the calibration by evaluating the CCCs within the 
 

530-24 

analysis batch. If the CCCs fail the criteria of Sect. 9.3.6.1, 

recalibration is in order per Sect.10.2. If the calibration standard is 

acceptable, extraction of the sample should be repeated, provided 

the sample is still available and within the holding time. If the reextracted sample also fails the recovery criterion, report all data for 

that sample as “suspect/surrogate recovery” to inform the data user 

that the results are suspect due to surrogate recovery. 

9.3.7. LABORATORY FORTIFIED SAMPLE MATRIX (LFSM) - Within each 

analysis batch of up to 20 Field Samples, analyze a minimum of one LFSM. The 

native concentrations of the analytes in the sample matrix must be determined in a 

second duplicate sample and subtracted from the measured values in the LFSM. If 

a variety of different sample matrices are analyzed regularly, for example, 

drinking water from ground water and surface water sources, performance data 

must be collected for each source. 

9.3.7.1. Prepare the LFSM by fortifying a Field Duplicate with an 

appropriate amount of analyte PDS (Sect. 7.2.3.2). Select a 

fortification concentration that is greater than or equal to the matrix 

background concentration, if known. Selecting a duplicate sample 

that has already been analyzed aids in the selection of an 

appropriate fortification concentration. If this is not possible, use 

historical data. If historical data are unavailable, rotate the 

fortifying concentrations for LFSMs between low, medium and 

high concentrations based on the calibration range. 

9.3.7.2. Calculate the percent recovery (%R) for each analyte using the 

equation 

 

  % 100 



C

BA

R

 where: 

 A = measured concentration in the fortified sample 

 B = measured concentration in the unfortified sample 

 C = fortification concentration. 

 Note: LFSMs and LFSMDs fortified at concentrations near the 

MRL, where the associated Field Sample contains native analyte 

concentrations above the DL but below the MRL, should be 

corrected for the native levels in order the obtain meaningful %R 

values. This example, and the LRB extrapolation (Sect. 9.3.1), are 

the only permitted uses of analyte results below the MRL. 
 

530-25 

9.3.7.3. Analyte recoveries may exhibit matrix bias. For samples fortified 

at or above their native concentration, recoveries should be within 

70-130% (50-130% for o-toluidine), except for low-level 

fortification near or at the MRL (within a factor of two times the 

MRL concentration) where 50-150% recoveries are acceptable. If 

the accuracy of any analyte falls outside the designated range, and 

the laboratory performance for that analyte is shown to be in 

control in the CCCs, the recovery is judged to be matrix biased. 

The quantitative result for that analyte in the unfortified sample is 

labeled “suspect/matrix” to inform the data user that the 

quantitative results may be suspect due to matrix effects. 

9.3.8. FIELD DUPLICATE OR LABORATORY FORTIFIED SAMPLE 

MATRIX DUPLICATE (FD or LFSMD) - Within each extraction batch, 

analyze a minimum of one Field Duplicate (FD) or Laboratory Fortified 

Sample Matrix Duplicate (LFSMD). Duplicates check the precision 

associated with sample collection, preservation, storage, and laboratory 

procedures. If target analytes are not routinely observed in Field Samples, 

an LFSMD should be analyzed rather than an FD. 

9.3.8.1. Calculate the relative percent difference (RPD) for duplicate 

measurements (FD1 and FD2) using the equation 

 

  100

2/21

21









FDFD

FDFD

RPD

9.3.8.2. RPDs for Field Duplicates should be ≤ 30 %. Greater variability 

may be observed when Field Duplicates have analyte 

concentrations that are within two times the MRL. At these 

concentrations, Field Duplicates should have RPDs that are ≤ 50%. 

If the RPD of any analyte falls outside the designated range, and 

the laboratory performance for that analyte is shown to be in 

control in the CCC, the recovery is judged to be affected by the 

matrix. The result for that analyte in the unfortified sample is 

labeled “suspect/matrix” to inform the data user that the 

quantitative results may be suspect due to matrix effects. 

9.3.8.3. If an LFSMD is analyzed instead of a Field Duplicate, calculate the 

relative percent difference (RPD) for duplicate LFSMs (LFSM and 

LFSMD) using the equation 

 

100

2/









LFSM LFSMD

LFSM LFSMD

RPD
 

530-26 

9.3.8.4. RPDs for duplicate LFSMs should be ≤ 30% for samples fortified 

at or above their native concentration. Greater variability may be 

observed when LFSMs are fortified at analyte concentrations that 

are within two times the MRL. LFSMs fortified at these 

concentrations should have RPDs that are ≤ 50% for samples 

fortified at or above their native concentration. If the RPD of any 

analyte falls outside the designated range, and the laboratory 

performance for that analyte is shown to be in control in the CCC, 

the recovery is judged to be affected by the matrix. The result for 

that analyte in the unfortified sample is labeled “suspect/matrix” to 

inform the data user that the quantitative results may be suspect 

due to matrix effects. 

9.3.9. QUALITY CONTROL SAMPLES (QCS) - As part of the IDC (Sect. 9.2), 

each time a new Analyte PDS (Sect. 7.2.3.2) or CAL solutions (7.2.4) are 

prepared, or at least quarterly, analyze a QCS sample from a source 

different from the source of the calibration standards. If a second vendor is 

not available then a different lot of the standard should be used. The QCS 

should be prepared and analyzed just like a CCC. Acceptance criteria for 

the QCS are identical to the CCCs; the calculated amount for each analyte 

must be ± 30% of the expected value. If measured analyte concentrations 

are not of acceptable accuracy, check the entire analytical procedure to 

locate and correct the problem. If the discrepancy is not resolved, one of the 

standard materials may be degraded or otherwise compromised and a third 

standard must be obtained. 

9.4. METHOD MODIFICATION QC REQUIREMENTS - The analyst is permitted to 

modify GC columns, GC conditions, GC injection techniques, extract evaporation 

techniques, MS conditions and quantitation ions (QIs). However, each time such 

method modifications are made, the analyst must repeat the procedures of the IDC 

(Sect. 9.2). 

9.4.1. Each time method modifications are made, the analyst must repeat the 

procedures of the IDC (Sect. 9.2) and verify that all QC criteria can be met 

in ongoing QC samples (Sect. 9.3). 

9.4.2. Each time method modifications are made, the analyst is also required to 

evaluate and document method performance for the proposed method 

modifications in real matrices that span the range of waters that the 

laboratory analyzes. This additional step is required because modifications 

that perform acceptably in the IDC, which is conducted in reagent water, 

can fail ongoing method QC requirements in real matrices. This is 

particularly important for methods subject to matrix effects. If, for example, 

the laboratory analyzes finished waters from both surface and groundwater 

municipalities, this requirement can be accomplished by assessing precision 

and accuracy (Sects. 9.2.2 and 9.2.3) in an analyte fortified surface water 
 

530-27 

with moderate to high TOC (e.g., 2 mg/L or greater) and an analyte fortified 

hard groundwater (e.g., 250 mg/L or greater as calcium carbonate). 

9.4.3. The results of Sects. 9.4.1 and 9.4.2 must be appropriately documented by 

the analyst and should be independently assessed by the laboratory’s 

Quality Assurance (QA) officer prior to analyzing Field Samples. When 

implementing method modifications, it is the responsibility of the 

laboratory to closely review the results of ongoing QC, and in particular, the 

results associated with the LFSMs (Sect. 9.3.7), FDs or LFSMDs 

(Sect. 9.3.8), CCCs (Sect. 9.3.2), and the IS area counts (Sect. 9.3.5). If 

repeated failures are noted, the modification must be abandoned. 

10. CALIBRATION AND STANDARDIZATION 

10.1. Demonstration and documentation of acceptable mass spectrometer tune and initial 

calibration is required before performing the IDC and prior to analyzing Field 

Samples. The MS tune check and initial calibration must be repeated each time a 

major instrument modification is made, or maintenance is performed. 

10.2. INITIAL CALIBRATION 

10.2.1. MS TUNE/MS TUNE CHECK - Calibrate the mass and abundance scales 

of the MS with calibration compounds and procedures prescribed by the 

manufacturer with any modifications necessary to meet tuning 

requirements. Inject 5 ng or less of the DFTPP solution (Sect. 7.2.5) into the 

GC/MS system. Acquire a mass spectrum that includes data for m/z 45 to 

450. The scan time should be set so that a minimum of five scans are 

acquired during the elution of the chromatographic peak. Seven to ten scans 

per chromatographic peak are recommended. Use a single spectrum at the 

apex of the DFTPP peak, an average spectrum of the three highest points of 

the peak, or an average spectrum across the entire peak to evaluate the 

performance of the system. If the DFTPP mass spectrum does not meet all 

criteria in Table 2, the MS must be retuned and adjusted to meet all criteria 

before proceeding with the initial calibration. The tune check should be 

conducted as described above for both full scan and SIM MS operation. 

10.2.2. INSTRUMENT CONDITIONS - Operating conditions used during method 

development are described below. Conditions different from those 

described may be used if QC criteria in Sect. 9 are met. Different conditions 

include alternate GC columns, temperature programs, MS conditions, and 

injection techniques and volumes, such as cold on-column and large volume 

injections. Equipment specifically designed for alternate types of injections 

must be used if these alternate options are selected. 

10.2.2.1. GC Conditions - Inject a 1-μL aliquot into a hot, splitless injection 

port held at 275 oC with a pressure pulse of 20 psi and a split delay 
 

530-28 

of 1 min. The temperature program is as follows: initial oven 

temperature of 60 oC, hold for 1 min, ramp at 10 oC/min to a final 

temperature of 290 oC and hold for 1 min. The GC is operated at a 

constant carrier gas flow rate of 1 mL/min. Total run time is 

approximately 25 min. Begin data acquisition at about seven min. 

10.2.2.2. Full Scan MS Acquistion Parameters - Select a scan range that 

allows the acquisition of a mass spectrum for each of the method 

analytes, which includes all of the major fragments m/z 45 and 

above. Adjust the cycle time to measure at least five spectra during 

the elution of each GC peak. Seven to ten scans across each GC 

peak are recommended. The chromatogram may be divided into 

time windows, also known as segments or periods, with different 

scan ranges for each time window. Minimizing the scan range for 

each time window may enhance sensitivity. If the chromatogram is 

divided into time windows, the laboratory must ensure that each 

method analyte elutes entirely within the proper window during 

each analysis. This can be achieved by carefully monitoring the 

retention times of all ISs and SURs in each sample, and carefully 

monitoring the retention times of all method analytes in CCCs, 

LFBs and LFSMs. This requirement does not preclude continuous 

operation by sequencing multiple analysis batches; however, the 

entire analysis batch is invalid if one or more analyte peaks have

drifted outside of designated time windows in the CCC at the 

beginning or end of the analysis batch. 

10.2.2.3. SIM MS Acquistion Parameters - Prior to selecting SIM 

parameters, analyze a mid- to high-concentration CAL in full scan 

mode. Select one primary QI and at least one secondary ion for 

confirmation. Suggested QIs and secondary ions for all method 

analytes are designated in Table 1, but these may be modified. An 

internal standard for each analyte is also designated in Table 1. 

Verify that the primary ion is free from interferences due to an 

identical fragment ion in any overlapping peak(s). Selection of the 

QI should be based on the best compromise between the intensity 

of the signal for that ion and the likelihood and intensity of 

interferences. The most intense ion may not be the best QI. 

However, the QI and secondary ions must be >30% relative 

abundance. Adjust the cycle time to measure at least five spectra 

during the elution of each GC peak. If the chromatogram is divided 

into time windows, the laboratory must ensure that each method 

analyte elutes entirely within the proper window during each 

analysis. This can be achieved by carefully monitoring the 

retention times of all ISs and SURs in each sample, and carefully 

monitoring the retention times of all method analytes in CCCs, 

LFBs and LFSMs. This requirement does not preclude continuous 
 

530-29 

operation by sequencing multiple analysis batches; however, the 

entire analysis batch is invalid if one or more analyte peaks have 

drifted outside of designated time windows in the CCC at the 

beginning or end of the analysis batch. The SIM parameters used 

during method development for selected analytes are provided in 

Table 6 as an example. 

10.2.2.4. Alternating Full and SIM Scan Modes - Alternating full and SIM 

scan modes during a single sample acquisition is permitted if the 

minimum number of scans across each GC peak acquired in each 

mode is maintained (as specified in Sect. 10.2.2.2 and 10.2.2.3), 

i.e., a minimum of five scans in full scan mode and a minimum of 

five scans in SIM mode. If the chromatogram is divided into time 

windows, the laboratory must ensure that each method analyte 

elutes entirely within the proper window during each analysis. This 

can be achieved by carefully monitoring the retention times of all 

ISs and SURs in each sample, and carefully monitoring the 

retention times of all method analytes in CCCs, LFBs and LFSMs. 

This requirement does not preclude continuous operation by 

sequencing multiple analysis batches; however, the entire analysis 

batch is invalid if one or more analyte peaks have drifted outside of 

designated time windows in the CCC at the beginning or end of the 

analysis batch. 

10.2.3. CALIBRATION SOLUTIONS - To establish a calibration range extending 

two orders of magnitude, prepare a set of at least six calibration standards as 

described in Sect. 7.2.4. The lowest concentration CAL must be at or below 

the MRL for each method analyte. The MRL must be confirmed using the 

procedure outlined in Sect. 9.2.4 after establishing the initial calibration. 

 Note: This method contains analytes that vary with regard to instrument 

sensitivity. If the analytes of interest differ in response, and the CAL 

standards have been prepared such that all analytes are at the same 

concentration, more standards may be needed to obtain the minimum six 

CAL points for each analyte. Analytes with poor response may not be 

observed in the low concentration standards, and the most responsive 

analytes may saturate the detector at the higher concentrations. It is likely 

that the calibration range for all analytes will not be the same. The use of 

custom calibration standards with varying analyte concentrations based on 

their relative instrument response is a possible alternative. 

10.2.4. CALIBRATION - Calibrate the GC/MS system using the internal standard 

technique in either full scan, SIM or alternating full scan/SIM mode. 

Subsequent sample analysis must be performed in the same calibration 

mode using identical instrument conditions and parameters. Internal 

standard designations and suggested QIs for all method analytes are listed in 
 

530-30 

Table 1. Table 6 contains example scanning parameters for selected 

analytes in SIM mode. Linear or quadratic calibrations may be used. 

Weighting may be used at the discretion of the analyst. 

10.2.5. CALIBRATION ACCEPTANCE CRITERIA - Validate the initial 

calibration curves by using the regression equations to calculate the 

concentration of each analyte as an unknown in each of the analyses used to 

generate the curves. Calibration points that are ≤ MRL must calculate to be 

within ± 50% of their true value. All other calibration points must calculate 

to be within ± 30% of their true value. If these criteria cannot be met, the 

analyst may eliminate either the highest or lowest point on the curve and 

reassess the acceptance criteria. If the acceptance criteria still cannot be 

met, the analyst will have difficulty meeting ongoing QC criteria. It is 

highly recommended that corrective action be taken before proceeding. 

This may include one or more of the following actions: analyze the 

calibration standards, further restrict the range of calibration, or select an 

alternate method of calibration. The data presented in this method were 

obtained using either linear regression or quadratic fits. Quadratic fit 

calibrations should be used with caution, because the non-linear area of the 

curve may not be reproducible. 

10.3. CONTINUING CALIBRATION CHECK (CCC) - Analyze a CCC to verify the 

initial calibration at the beginning of each analysis batch, after every tenth Field 

Sample, and at the end of each analysis batch. The beginning CCC for each analysis 

batch must be at or below the MRL. This CCC verifies instrument sensitivity prior to 

the analysis of samples. Alternate subsequent CCCs between the remaining 

calibration levels. 

Note: If standards have been prepared such that all analytes are not in the same 

calibration standard (or all low CAL points are not in the same CAL standard), it 

may be necessary to analyze more than one CCC to meet this requirement. 

Alternatively, it may be cost effective to prepare or obtain a customized standard to 

meet this criterion. 

10.3.1. Verify that the peak area of the QI of each IS has not changed by more than 

± 50% from the mean peak area measured for that IS during initial 

calibration. In addition, verify that the peak area of the QI of each of the 

two ISs are within ± 30% from the most recently analyzed CCC. If these 

limits are exceeded, remedial action must be taken (Sect. 10.3.3). Control 

charts are useful aids in documenting system sensitivity changes. 

10.3.2. Calculate the concentration of each analyte and surrogate in the CCC. The 

calculated amount for each analyte for medium and high level CCCs must 

be ± 30% of the true value. The calculated amount for the lowest calibration 

level for each analyte must be within ± 50% of the true value. If these 

criteria are not met, then all data for the problem analyte must be considered 
 

530-31 

invalid, and remedial action (Sect. 10.3.3) must be taken. Recalibration may 

be required. Any Field Sample extracts that have been analyzed since the 

last acceptable calibration verification should be reanalyzed after adequate 

calibration has been restored, with the following exception. If the CCC at 

the end of an analysis batch fails because the calculated concentration is 

greater than 130% (150% for the low-level CCC) for a particular target 

analyte, and Field Sample extracts show no detection for that target 

compound, non-detects may be reported without reanalysis. 

10.3.3. REMEDIAL ACTION - Failure to meet CCC QC performance criteria may 

require remedial action. Major maintenance such as cleaning an ion source, 

cleaning the mass analyzer, replacing filament assemblies, or replacing the 

GC column, etc., will require returning to the initial calibration step 

(Sect. 10.2). 

11. PROCEDURE 

11.1. This section describes the procedures for sample preparation, SPE, final extract 

preparation and storage, and extract analysis. Important aspects of this analytical 

procedure include proper preparation of laboratory glassware, sample containers 

(Sect. 4.1), and sample collection and storage (Sect. 8). Procedures for data analysis 

and calculations are described in Sect. 12.

11.2. SAMPLE PREPARATION 

11.2.1. Samples are preserved, collected and stored as described in Sect. 8. All field 

and QC samples, including LRBs and LFBs, must contain the preservatives 

listed in Sect. 8.1.2. Mark the level of the sample on the outside of the 

sample bottle for later sample volume determination. If using weight to 

determine volume (Sect. 11.6), weigh the bottle and sample contents before 

extraction. 

11.2.2. Add an aliquot of the SUR PDS(s) to each sample to be extracted. For full 

scan method development work, a 10-μL aliquot of each of the 500-μg/mL 

SUR PDSs (Sect. 7.2.2) was added to 1 L samples for a final concentration 

of 5.0 μg/L. 

11.2.3. If the sample is an LFB, LFSM, or LFSMD, add the necessary amount of 

Analyte Fortification Solution(s) (Sect. 7.2.3.2). Swirl each sample to 

ensure all components are mixed. 

11.2.4. Proceed with sample extraction using the SPE procedure described in Sect. 

11.3.

11.3. CARTRIDGE SPE (6 mL) PROCEDURE - This cartridge extraction procedure may 

be carried out in a manual mode or by using a robotic or automatic sample 
 

530-32 

preparation device. This section describes the SPE procedure using the equipment 

outlined in Sects. 6.9-6.11 in its simplest, least expensive mode without the use of a 

robotic system. The manual mode described below was used to collect data presented 

in Sect. 17. The extraction steps are written for an individual sample, but multiple 

samples may be extracted simultaneously depending upon the extraction equipment 

used.

11.3.1. CARTRIDGE CLEANUP - Install the SPE cartridge (Oasis HLB, 

Phenomenex Strata-X, or Agilent Bond Elut Plexa as described in Sect. 

6.9.1) into the vacuum manifold. For alternate sorbents, see Sect. 6 

regarding sorbent equivalency. Wash the cartridge with 5 mL of DCM by 

adding the solvent to the cartridge; draw about half through the sorbent, 

soak for about one min, then draw the remaining solvent through the 

cartridge. 

11.3.2. CARTRIDGE CONDITIONING - Polymeric SPE sorbents are water 

wettable (unlike C-18 SPE sorbents). Many manufacturers of polymeric 

SPE media suggest that their products do not need to be kept wet during 

conditioning and sample processing. However, little data have been shown 

to demonstrate performance under those conditions for the wide variety of 

environmental contaminants using these media. Therefore, in the interest of 

providing a single procedure for the sorbents and analytes in this method, 

the authors chose to use procedures similar to those used with C-18 where 

the sorbent is kept wet. 

11.3.2.1. CONDITIONING WITH METHANOL - Add 10 mL MeOH to 

the cartridge and allow it to soak for about one min. Then draw 

most of the MeOH through. A layer of MeOH must be left on the 

surface of the cartridge. Do NOT let the cartridge go dry from this 

point on until the end of sample extraction.

11.3.2.2. CONDITIONING WITH WATER - Rinse the cartridge by adding 

10 mL of reagent water to the cartridge and drawing most through, 

again leaving a layer on the surface of the cartridge. 

11.3.3. SAMPLE EXTRACTION - Attach a PTFE transfer line to the top of the 

cartridge. Insert the opposite end of the transfer line into the sample to be 

extracted. Apply vacuum to begin the extraction. Adjust the vacuum so that 

the sample passes through the cartridge at a rate of about 10 mL/min. Pass 

the entire sample volume through the cartridge, draining as much water 

from the sample container as possible. Rinse the bottle with 10 mL LRW 

and transfer to the cartridge under full vacuum. Rinsing the sorbent with 

LRW prior to drying helps remove sample preservatives from the sorbent so 

they are not transferred to the extract. Remove the sample transfer line from 

the cartridge and dry by maintaining vacuum for about 10 min. 
 

530-33 

11.3.4. CARTRIDGE ELUTION - Remove the manifold lid (but do not remove the 

cartridge) and insert a suitable collection tube to contain the eluent (15-mL 

collection vial). Reassemble the apparatus. Add ~2 mL of acetone to the 

sample bottle, and rinse the inside walls thoroughly. Allow the solvent to 

settle to the bottom of the bottle, then transfer it to the cartridge. Draw the 

solvent through the cartridge by applying vacuum. Add 5 mL of DCM to 

the sample bottle, and rinse the inside walls thoroughly. Allow the solvent 

to settle to the bottom of the bottle, and then transfer to the cartridge by 

applying vacuum. Draw about half of the solvent through the cartridge, cut 

off vacuum at the cartridge, and allow the cartridge to soak for one min. 

Draw the remaining solvent through the cartridge. Repeat the above step 

with another 5 mL of DCM. Shut off vacuum, remove the transfer line, and 

remove the collection vial. Proceed to Sects. 11.4 and 11.5 to dry and 

concentrate the extract. 

11.4. DRYING THE EXTRACT - Transfer the combined eluent through a drying tube 

containing about 7 g of anhydrous sodium sulfate. Rinse the collection tube with 

3 mL DCM, and then put the DCM through the sodium sulfate. Collect the dried 

extract and DCM rinse in a clean collection tube. 

11.5. EXTRACT CONCENTRATION - Concentrate the extract to about 0.7 mL under a 

gentle stream of nitrogen gas in a warm water bath (at ~ 40 oC). Do not blow down 

samples to less than 0.5 mL, because the more volatile compounds will exhibit 

diminished recovery. Transfer the extract to a 1-mL volumetric flask and add the 

internal standards (Sect. 7.2.1). Rinse the collection tube that held the dried extract 

with small amounts of DCM and add to the volumetric flask to bring the volume up 

to the 1-mL mark. Transfer to an autosampler vial. Store extracts at -5 oC or less until 

analysis. 

11.6. SAMPLE VOLUME OR WEIGHT DETERMINATION - Use a graduated cylinder 

to measure the volume of water required to fill the original sample bottle to the mark 

made prior to extraction (Sect. 11.2.1). Determine volume to the nearest 10 mL for 

use in the final calculations of analyte concentration (Sect. 12.2). If using weight to 

determine volume, reweigh the empty sample bottle. Subtract the empty bottle 

weight from the weight of the original combined bottle/sample weight measured in 

Sect. 11.2.1. To calculate the sample volume from its weight , assume a sample 

density of 1 g/mL. Use the calculated sample volume for analyte concentration 

calculations in Sect.12.2. 

11.7. ANALYSIS OF SAMPLE EXTRACTS 

11.7.1. Establish instrument operating conditions as described in Sect. 10.2.2. 

Confirm that compound separation and resolution are similar to those 

summarized in Table 1 and Figure 1. 
 

530-34 

11.7.2. Establish a valid initial calibration following the procedures outlined in 

Sect. 10.2 or confirm that the calibration is still valid by running a CCC as 

described in Sect. 10.3. If establishing an initial calibration for the first 

time, complete the IDC as described in Sect. 9.2. 

11.7.3. Analyze aliquots of Field and QC Samples at appropriate frequencies 

(Sect. 9) with the GC/MS conditions used to acquire the initial calibration 

and the CCC. At the conclusion of data acquisition, use the same software 

that was used in the calibration procedure to tentatively identify peaks in 

predetermined retention time windows of interest. Use the data system 

software to examine the ion abundances of components of the chromatogram to confirm identity. 

12. DATA ANALYSIS AND CALCULATIONS 

12.1. COMPOUND IDENTIFICATION - Identify sample components by comparison of 

their retention times and mass spectra to the reference retention times and spectra in 

the user-created data base as follows: 

12.1.1. Establish an appropriate retention time window for each analyte, internal 

standard and surrogate analyte to identify them in QC and Field Sample 

chromatograms. Ideally, the retention time window should be based on 

measurements of actual retention time variation for each compound in 

standard solutions collected on each GC/MS over the course of time. The 

suggested variation is plus or minus three times the standard deviation of 

the retention time for each compound for a series of injections. The 

injections from the initial calibration and from the IDC (Sect. 9.2) may be 

used to calculate a suggested window size. However, the experience of the 

analyst should weigh heavily on the determination of an appropriate 

retention window size. 

12.1.2. Each compound should be identified from its reference spectrum obtained 

during the acquisition of the initial calibration curve. The mass spectrum 

used for identification of each compound is acquired in the full scan or SIM 

mode. 

12.1.2.1. Full Scan MS Identification - In general, all ions that are present at 

or above 30% relative abundance in the mass spectrum of the 

reference standard obtained during calibration should be present in 

the mass spectrum of the sample component and should agree 

within an absolute 20%. For example, in full scan mode, if an ion 

has a relative abundance of 30% in the standard spectrum, its 

abundance in the sample spectrum should be in the range of 

10-50%. 
 

530-35 

12.1.2.2. SIM MS Identification - In SIM mode, all ions monitored in the 

standard should be present in the SIM mass spectrum of the sample 

component and relative abundance from integrated peak areas 

should agree within absolute 20%. For example, if an ion has a 

relative abundance of 30% in the standard spectrum, its abundance 

in the sample spectrum should be in the range of 10-50%. 

Secondary ions should have a relative abundance of >30% in the 

standard. The IS phenanthrene-d10 does not have a secondary 

ion with a relative abundance of >30%, therefore no relative 

abundance calculation for compound confirmation is required.

12.1.3. Identification is hampered when sample components are not resolved 

chromatographically and produce mass spectra containing ions contributed 

by more than one analyte. When GC peaks obviously represent more than 

one sample component (i.e., broadened peak with shoulder(s) or valley 

between two or more maxima), appropriate analyte spectra and background 

spectra can be selected by examining plots of characteristic ions. Comparing 

a background subtracted spectrum to the reference spectrum is suggested. If 

two or more analytes coelute but only one GC peak is apparent, the 

identification criteria can be met but each analyte spectrum will contain 

extraneous ions contributed by the coeluting compound. 

12.1.4. BHA exists as two structural isomers, 2-BHA and 3-BHA, which 

commonly appear as one chromatographic peak. Structural isomers that 

produce very similar mass spectra can be explicitly identified only if they 

have sufficiently different GC retention times. Acceptable resolution is 

achieved if the height of the valley between two isomer peaks is <25% of 

the average height of the two isomer peaks. Otherwise, combine the peak 

areas of the isomers and quantify and identify as an isomeric pair. 

12.2. QUANTITATION AND CALCULATIONS 

12.2.1. Calculate analyte and surrogate concentrations using the multipoint 

calibration established in Sect. 10.2. In validating this method, 

concentrations were calculated by measuring the characteristic ions listed in 

Table 1. Other ions may be selected at the discretion of the analyst. Do not 

use daily continuing calibration check data to quantitate analytes in 

samples. Adjust the final analyte concentrations to reflect the actual sample 

volume determined in Sect. 11.6. Field Sample extracts that require dilution 

should be treated as described in Sect. 12.2.2.

12.2.2. If the calculated amount of any analyte exceeds the calibration range of the 

curve, the extract must be diluted with DCM, with the appropriate amount 

of additional internal standard added to match the original concentration. 

Analyze the diluted extract. Acceptable surrogate performance (Sect. 9.3.6) 

should be determined from the undiluted sample extract. Incorporate the 
 

530-36 

dilution factor into final concentration calculations. The resulting sample 

should be documented as a dilution, and MRLs should be adjusted 

accordingly. If matrix-matched calibration standards are being used, the 

dilution may be made with DCM, but care should be taken to dilute just 

enough to position the analyte within the calibration range. Excessive 

dilution and resulting low concentration may affect the accuracy of the final 

measurement. 

12.2.3. Calculations must utilize all available digits of precision, but final reported 

concentrations should be rounded to an appropriate number of significant 

figures (one digit of uncertainty), typically two, and not more than three 

significant figures.

 Note: Some data in Sect. 17 of this method are reported with more than two 

significant figures. This is done to better illustrate the method performance 

data. 

13. METHOD PERFORMANCE 

13.1. PRECISION AND ACCURACY DATA 

13.1.1. FULL SCAN GC/MS - Precision and accuracy data were collected from 

LFBs at three concentration levels using sorbents described in Sect. 6.9.1. 

Precision and accuracy data were also collected at a single fortified 

concentration using two challenging water matrices. Tap water matrices 

were selected to be representative of ground water with high mineral 

content and surface water with a moderate level of TOC. Precision and 

accuracy data in both fortified reagent water and fortified matrices are 

presented in Tables 3 and 4. 

13.1.2. SIM GC/MS - The SIM GC/MS analysis option may be used for added 

analyte sensitivity. Precision and accuracy data were collected using LFBs 

fortified at three concentration levels. Precision and accuracy data were also 

collected at a single fortified concentration using two challenging water 

matrices. Tap water matrices were selected to be representative of ground 

water with high mineral content and surface water with a moderate level of 

TOC. Precision and accuracy data in both fortified reagent water and 

fortified matrices are presented in Tables 7 and 8. 

13.2. LCMRLs and DLs 

13.2.1. FULL SCAN GC/MS - The DL and LCMRL values for all analytes in full 

scan mode are presented in Table 5. 

13.2.2. SIM GC/MS - The DL and LCMRL values for all analytes in SIM are 

presented in Table 9. 
 

530-37 

13.3. SAMPLE STORAGE STABILITY STUDIES - Drinking water samples from a 

chlorinated surface source were used as a representative matrix for an analyte 

holding time study in aqueous solution. Replicate samples in amber bottles were 

preserved as described in Sect. 8, fortified with method analytes, then stored for 

48 hours at 10 oC, followed by storage at 4 oC until analysis. Randomly selected 

samples were analyzed in replicate (n=4) on day 0 and at several time points up to 

the 14 day holding time. Data from days 0, 7 and 14 are presented in Fig. 2. These 

data were used to establish the 14 day aqueous holding time for method analytes 

(Sect. 8.4). 

 Notes: 

 Surrogate analytes were not stored in this study, but added at the time of 

extraction. The data in Fig. 2 for SURs are same day data, obtained for QC 

purposes. 

 Holding time studies conducted during method development indicated moderate 

analyte losses (more than 10% in 14 days, with increasing loss at subsequent 

time points) for o-toluidine using the sample collection, preservation and holding 

time procedures in this method. o-Toluidine exhibited a loss of 11% at 7 days 

and 14% at 14 days. 

13.4. EXTRACT STORAGE STABILITY STUDIES - Replicate sample extracts (n=4) 

that were stored at -5 oC and protected from light, were analyzed on days 0, 7 and 14. 

Data from these analyses validate the 14 day extract holding time and are presented 

in Fig. 3. 

Notes: 

 Surrogate analytes were stored in this study, added at the time of extraction. 

 Extract holding time studies conducted during method development indicated 

significant analyte losses (more than 15% in 14 days, with increasing loss at 

subsequent time points) for o-toluidine using the sample collection, preservation 

and holding time procedures in this method. o-Toluidine in extracts exhibited a 

loss of 13% at 7 days and 16% at 14 days. The SUR o-toluidine-d9 shows similar 

losses in extracts over time. 

13.5. POTENTIAL PROBLEMS/ PROBLEM COMPOUNDS 

13.5.1. MATRIX INDUCED CHROMATOGRAPHIC RESPONSE 

ENHANCEMENT (MICRE) - BHA has the potential to exhibit a high bias. 

The bias has been attributed to the phenomenon of MICRE. Examples of 

this are shown in Table 8 for BHA, which show recovery data for fortified 

tap waters that approach 130% of the fortified amount. Data in Table 4

show that this phenomenon is related to analyte concentration, since the 

high bias is not observed at the higher fortified concentration. Although the 

use of matrix-matched standards will improve quantitative accuracy for 

BHA, a bias may still be observed. In addition to the use of matrix matched 
 

530-38 

standards, “priming” the GC system by injecting one or more sample 

extracts at the beginning of each analytical sequence was found to reduce 

matrix enhancement effects. Literature citations suggest that temperature 

programmed or cold injections may also reduce matrix enhancement,12,13,18

although trials of these types of injections during method development 

showed little or no improvement. The biased data were instrument 

dependent, and not related to the sorbent used. Similar tap water extracts 

generated using different sorbent options listed in this method, showed 

similarly high biased data on the same instrument. 

Depending upon the intended use of the data, the analyst should consider 

performing the MRL verification (Sect. 9.2.4.4) in fortified matrices similar 

to the samples being analyzed. 

13.5.2. OVERDRYING SPE MEDIA PRIOR TO ELUTION – If SPE media is 

over dried between sample loading and solvent elution by drawing 

excessive amounts of room air through the media, analytes that can undergo 

oxidation may be observed to have low recoveries. An example of an 

analyte that may be affected is o-toluidine.

13.6. MULTIPLE LABORATORY DEMONSTRATION - The performance of this 

method was demonstrated by three independent laboratories. These laboratories 

produced acceptable results and provided valuable method performance data. The 

author wishes to acknowledge the assistance of the analysts and managers at the 

laboratories listed below for their participation in the multi-laboratory study. 

13.6.1. Dr. Yongtao Li and Mr. William Davis of Eurofins Eaton Analytical, Inc., 

South Bend, IN. 

13.6.2. Mr. Kevin Durk and Ms. Annmarie Walsh of Suffolk County Water 

Authority, Hauppauge, NY. 

13.6.3. Dr. Andrew Eaton and Mr. Patrick Chapman of Eurofins Eaton Analytical, 

Inc., Monrovia, CA. 

14. POLLUTION PREVENTION

14.1. This method utilizes SPE to extract analytes from water. It requires the use of very 

small volumes of organic solvent and very small quantities of pure analytes, thereby 

minimizing the potential hazards to both the analyst and the environment as 

compared to the use of large volumes of organic solvents in conventional liquidliquid extractions. 
 

530-39 

14.2. For information about pollution prevention that may be applicable to laboratory 

operations, consult “Less is Better: Guide to Minimizing Waste in Laboratories” 

available on-line from the American Chemical Society at http://www.acs.org/content/ 

dam/acsorg/about/governance/committees/chemicalsafety/publications/less-isbetter.pdf.

15. WASTE MANAGEMENT

15.1. The analytical procedures described in this method generate relatively small amounts 

of waste since only small amounts of reagents and solvents are used. The matrices of 

concern are finished drinking water or source water. However, the Agency requires 

that laboratory waste management practices be conducted consistent with all 

applicable rules and regulations, and that laboratories protect the air, water, and land 

by minimizing and controlling all releases from fume hoods and bench operations. 

Also, compliance is required with any sewage discharge permits and regulations, 

particularly the hazardous waste identification rules and land disposal restrictions. 

16. REFERENCES 

1. Winslow, S.D., Pepich, B.V., Martin, J.J., Hallberg, G.R., Munch, D.J., Frebis, C.P., 

Hedrick, E.J., Krop, R.A., Statistical Procedures for Determination and Verification of 

Minimum Reporting Levels for Drinking Water Methods, Environ. Sci. Technol., 2006, 40, 

281-288. 

2. Martin, J.J., Winslow, S.D., Munch, D.J., A New Approach to Drinking Water Quality Data: 

Lowest Concentration Minimum Reporting Level, Environ. Sci. Technol., 2007, 41, 677-681. 

3. Glaser, J.A., Foerst, D.L., McKee, G.D., Quave, S.A., Budde, W.L., Trace Analyses for 

Wastewaters, Environ. Sci. Technol., 1981, 15, 1426-1435. 

4. Erney, D.R., Gillespie, A.M., Gilvydis, D.M., Poole, C.F., Explanation of the Matrix-Induced 

Chromatographic Response Enhancement of Organophosphorous Pesticides During Open 

Tubular Column Gas Chromatography with Splitless or Hot On-Column Injection and Flame 

Photometric Detection, J. Chromatogr., 1993, 638, 57-63. 

5. Mol, H.G.J., Althuizen, M., Janssen, H., Cramers, C.A., Brinkman, U.A.Th., Environmental 

Applications of Large Volume Injection in Capillary GC Using PTV Injectors, J. High Resol. 

Chromatogr., 1996, 19, 69-79. 

6. Erney, D.R., Pawlowski, T.M., Poole, C.F., Matrix Induced Peak Enhancement of Pesticides 

in Gas Chromatography, J. High Resol. Chromatogr., 1997, 20, 375-378. 

7. Hajslova, J., Holadova, K., Kocourek, V., Poustka, J., Godula, M., Cuhra, P., Kempny, M., 

Matrix Induced Effects: A Critical Point in the Gas Chromatographic Analysis of Pesticide 

Residues, J. Chromatogr., 1998, 800, 283-295. 
 

530-40 

8. Wylie, P., Uchiyama, M., Improved Gas Chromatographic Analysis of Organophosphorous 

Pesticides with Pulsed Splitless Injection, J. AOAC International, 1996, 79, 571-577. 

9. Hajslova, J., Zrostlikova, J., Matrix Effects in (Ultra) Trace Analysis of Pesticide Residues in 

Food and Biotic Matrices, J. Chromatog. A, 2003, 1000,181-197. 

10. Anastassiades, M., Mastovska, K., Lehotay, S.J., Evaluation of Analyte Protectants to 

Improve Gas Chromatographic Analysis of Pesticides, J. Chromatog. A, 2003, 1015,163-184. 

11. Poole, C.F., Matrix Induced Response Enhancement in Pesticide Residue Analysis by Gas 

Chromatography, J. Chromatog. A, 2007, 1158, 241-250. 

12. Thurman, E.M., Mills, M.S., Solid Phase Extraction Principles and Practice, John Wiley and 

Sons, Inc., 1998, p. 66. 

13. Prudent Practices in the Laboratory: Handling and Disposal of Chemicals, National 

Academies Press (2011 updated version), ISBN: 9780309138642. 

14. OSHA Safety and Health Standards, General Industry, (29CFR1910), Occupational Safety 

and Health Administration, OSHA 2206, (Revised, July 2001).

15. Safety in Academic Chemistry Laboratories, American Chemical Society Publication, 

Committee on Chemical Safety, 7th Edition. Available online at 

http://portal.acs.org/portal/PublicWebSite/about/governance/committees/chemicalsafety/publ

ications/WPCP_012294 (accessed October 5, 2011). 

 

16. Technical Notes on Drinking Water Methods, 1994, EPA Document #600/R-94/173. 

Available through EPA’s digital publications National Environmental Publications Internet 

Site (NPEIS) database. 

17. USEPA Office of Ground Water and Drinking Water, Technical Support Center, Alternate 

Test Procedure Coordinator, 26 W. Martin Luther King Dr., Cincinnati, OH, 45268. 

18. Szelewski, M., Environmental Semivolatiles Using an Agilent Multimode Inlet for 

Maximum Sensitivity - Application Note. Agilent Technologies, Inc. 2850 Centerville Rd., 

Wilmington, DE 19809-1610. 

19. Price, E.K., Prakash, B., Domino, M.M., Pepich, B.V., Munch, D.J., Method 527. 

Determination of Selected Pesticides and Flame Retardants in Drinking Water by Solid Phase 

Extraction and capillary Gas Chromatography/ Mass Spectrometry, 2005, EPA Document 

#815-R-05-005. Available on-line at 

http://www.epa.gov/ogwdw/methods/pdfs/methods/met527.pdf (accessed January 20, 2015).
 

530-41 

17. TABLES, FIGURES AND VALIDATION DATA

Table 1. Retention Times (RTs), Suggested Quantitation Ions (QIs), Suggested SIM 

Secondary Ions, and Suggested Internal Standard Reference

Peak 

Identification #, 

Figure 1

RT 

(min)

Internal Standards, Analytes and 

Surrogates IS Ref. # QI (m/z)

SIM 

Secondary

Ion(s) (m/z) Comments

5 12.66 acenaphthene-d10 (IS 1) 162 164 a

7 16.39 phenanthrene-d10 (IS 2) 188 --* a

1 7.73 o-toluidine-d9 (SUR) 1 114 112 b

2 7.78 o-toluidine 1 106 107 b

3 9.84 quinoline-d7 (SUR) 1 136 108 b

4 9.86 quinoline 1 129 102 b

6 13.68 BHA 2 180 137 b, c

8 18.36 dimethipin 2 54 118 b

 * No secondary ion present at >30% relative abundance. 

Comment Key 

a. PDS solvent, acetone 

b. PDS solvent, methanol 

c. Potential to exhibit matrix induced chromatographic response enhancement was observed during method 

development. This assessment was done based on a peak area comparison of a standard prepared in solvent 

compared to a matrix-matched standard, both at a concentration of 0.1 ng/μL. If the matrix-matched standard 

area was ≥130% of the solvent prepared standard, the analyte was flagged as having the potential for matrix 

induced chromatographic response enhancement. 
 

530-42 

Table 2. Ion Abundance Criteria for Decafluorotriphenyl Phosphine (DFTPP)a

Mass (m/z) Relative Abundance Criteria Purpose of Checkpointb

68 <2% of m/z 69 Low-mass resolution

69 present Low-mass resolution

70 <2% of m/z 69 Low-mass resolution

197 <2% of m/z 198 Mid-mass resolution

198 present c Mid-mass resolution and sensitivity

199 5-9% of m/z 198 Mid-mass resolution and isotope ratio

365 >1% of base peak Baseline threshold

441 <150% of m/z 443 High-mass resolution

442 present c High-mass resolution and sensitivity

443 15-24% of m/z 442 High-mass resolution and isotope ratio

a. These ion abundance criteria have been developed specifically for target compound analysis 

as described in this method. Adherence to these criteria may not produce spectra suitable for 

identifying unknowns by searching commercial mass spectral libraries. If the analyst intends 

to use data generated with this method to identify unknowns, adherence to stricter DFTPP 

criteria as published in previous methods19 is recommended. 

b. All ions are used primarily to check the mass accuracy of the mass spectrometer and data 

system, and this is the most important part of the performance test. The three sets of 

resolution checks, which include natural abundance isotope ratios, constitute the next most 

important part of the performance test, followed by the correct setting of the baseline 

threshold, as indicated by the presence of m/z 365. 

c. Either m/z 198 or 442 is typically the base peak. 
 

530-43 

Table 3. Precision and Accuracy Data Obtained for Method Analytes Extracted from 

Fortified Reagent Water at Three Concentrations; Full Scan GC/MS Analyses

Analytes 

Fortified Conc.

0.10 μg/L*

n=4

Fortified Conc.

1.0 μg/L*

n=4

Fortified Conc.

5.0 μg/L*

n=4

Mean % 

Recovery RSD Mean % Recovery RSD Mean % Recovery RSD

o-toluidine-d9 (SUR) 87.2 1.7 90.8 1.9 89.0 3.0

o-toluidine 101 24 94.2 2.9 84.6 2.3

quinoline-d7 (SUR) 103 0.70 104 3.9 105 1.7

quinoline 123 16 112 2.7 99.2 1.1

BHA 110 13 104 2.8 90.8 2.5

dimethipin 91.5 9.2 105 5.1 99.0 2.3

 * Surrogate concentrations are 5.0 μg/L 

a. Tap water from a ground water source with high mineral content. Tap water hardness was 376 mg/L as calcium 

carbonate. 

b. Tap water from a surface water source. TOC of 2.0 mg/L. 

c. Recoveries have been corrected to reflect the native amount in the unfortified matrix water. 

Table 4. Precision and Accuracy Data Obtained for Method Analytes Extracted from 

Fortified Finished Drinking Waters from Ground and Surface Water; n=4 for Each 

Matrix; Full Scan GC/MS Analyses

Analytes

Fortified 

Conc. (μg/L)

Ground Watera Surface Waterb

Mean % 

Recoveryc RSD Mean % Recoveryc RSD

o-toluidine-d9 (SUR) 1.0 87.0 1.7 73.1 6.1

o-toluidine 1.0 86.0 2.2 71.3 1.3

quinoline-d7 (SUR) 1.0 98.5 1.4 89.3 4.2

quinoline 1.0 97.6 1.2 86.6 2.6

BHA 1.0 99.2 7.5 97.9 3.5

dimethipin 1.0 106 3.7 93.4 3.5
 

530-44 

Table 5. DLs and LCMRLs (μg/L) Calculated from Replicate Analyses of Fortified Reagent 

Water Samples Analyzed in Full Scan GC/MS Mode 

Analytes DL*

Fortified conc. of DL 

replicates LCMRL

o-toluidine 0.007 0.05 0.011

quinoline 0.036 0.05 0.084

BHA 0.044 0.05 0.062

dimethipin 0.037 0.05 0.075

* DL calculated from eight replicates. 

* No secondary ion present at >30% relative abundance. 

Table 6. Example SIM Parameters for Method Analytes

SIM 

Segment Compound

RT 

(min)

QI 

(m/z)

Secondary

Ion(s) (m/z)

Dwell 

Time 

(ms)

Scan Rate

(scan/sec)

# 1 o-toluidine-d9 (SUR) 8.84 114 112 75 3.1

o-toluidine 8.89 106 107

# 2 quinoline-d7 (SUR) 11.05 136 10875 3.1

quinoline 11.07 129 102

# 3 acenaphthene-d10 (IS 1) 13.91 162 164 75 3.1

BHA 14.92 180 137

# 4 phenanthrene-d10 (IS 2) 17.77 188 --* 100 8.3

# 5 dimethipin 19.83 54 118 100 4.5
 

530-45 

* Surrogate concentrations are 0.50 μg/L. 

a. Tap water from a ground water source with high mineral content. Tap water hardness was 359 mg/L as calcium 

carbonate. 

b. Tap water from a surface water source. TOC of 5.7 mg/L. 

Table 7. Precision and Accuracy Data Obtained for Method Analytes Extracted from 

Fortified Reagent Water at Three Concentrations; SIM GC/MS Analyses

Analytes 

Fortified Conc.

0.01 μg/L*

n=4 

Fortified Conc.

0.10 μg/L*

n=4

Fortified Conc.

0.50 μg/L*

n=4

Mean % 

Recovery RSD Mean % Recovery

Mean % 

Recovery

Mean % 

Recovery RSD

o-toluidine-d9 (SUR) 88.9 3.2 85.3 6.8 91.4 9.4

o-toluidine 98.8 22 97.5 6.5 101 8.4

quinoline-d7 (SUR) 107 1.8 107 3.2 102 4.3

quinoline 112 2.5 93.5 3.3 105 5.3

BHA 137 11 116 9.0 112 8.9

dimethipin 121 15 126 2.9 116 1.2

Table 8. Precision and Accuracy Data Obtained for Method Analytes Extracted from 

Fortified Finished Drinking Waters from Ground and Surface Water; n=4 for Each 

Matrix; SIM GC/MS Analyses

Analytes

Fortified 

Conc. (μg/L)

Ground Watera Surface Waterb

Mean % 

Recoveryc RSD Mean % Recoveryc RSD

o-toluidine-d9 (SUR) 0.10 90.4 3.4 75.1 3.4

o-toluidine 0.10 87.7 2.1 71.8 4.5

quinoline-d7 (SUR) 0.10 103 3.0 125 2.5

quinoline 0.10 108 2.9 116 3.3

BHA 0.10 124 2.6 127 2.2

dimethipin 0.10 106 2.4 102 2.7
 

530-46 

Table 9. DLs and LCMRLs (μg/L) Calculated from Replicate Analyses of Fortified Reagent 

Water Samples Analyzed in SIM GC/MS Mode 

Analytes DL*

Fortified conc. of 

DL replicates LCMRL

o-toluidine 0.001 0.005 0.003

quinoline 0.003 0.005 0.005

BHA 0.003 0.005 0.013

dimethipin 0.001 0.005 0.003

 * DL calculated from eight replicates. 
 

530-47 

Table 10. Initial Demonstration of Capability (IDC) and Quality Control (QC) Requirements (Summary)

Method 

Reference

Requirement Specification and Frequency Acceptance Criteria

Sect. 9.2.1

& 9.3.1

Initial Demonstration of 

Low Background

Analyze LRB prior to any other IDC steps. When a new 

lot of SPE media is obtained, verify that background is 

at acceptable limits.

Demonstrate that the method analytes are ≤ 1/3 the 

MRL, and that possible interferences from 

extraction media do not prevent the identification 

and/or quantification of any analytes, SURs or ISs. 

Note: This includes the absence of interferences at

both the QIs and secondary ions at the RTs of 

interest.

Sect. 9.2.2 Initial Demonstration of 

Precision (IDP)

Analyze four to seven replicate LFBs fortified near the 

midrange calibration concentration. %RSD must be  20%

Sect. 9.2.3 Initial Demonstration of 

Accuracy (IDA)

Calculate average recovery for replicates used in IDP. Mean recovery  30% of the true value for all 

analytes except o-toluidine, which must be within 

50-130% of the true value

Sect. 9.2.4 Minimum Reporting 

Limit (MRL) 

Confirmation 

Fortify, extract and analyze seven replicate LFBs at the 

proposed MRL concentration. Calculate the mean, 

standard deviation and HRPIR for each analyte. Confirm 

that the upper and lower limits for the Prediction 

Interval of Result (Upper PIR, and Lower PIR, Sect. 

9.2.4.2) meet the recovery criteria. 

Upper PIR  150%

Lower PIR  50% 

Sect. 9.2.5 

& 9.3.9

Calibration Confirmation,

Quality Control Sample 

(QCS)

Analyze a standard from a second source (QCS) to 

verify the initial calibration curve. ± 30% of the expected value.

NOTE: Table 10 is intended as an abbreviated summary of QC requirements provided as a convenience to the method user. Because the information has been 

abbreviated to fit the table format, there may be issues that need additional clarification, or areas where important additional information from the method text 

is needed. In all cases, the full text of the QC in Sect. 9 supersedes any missing or conflicting information in this table. 
 

530-48 

Table 11. Ongoing Quality Control (QC) Requirements (Summary) 

Method 

Reference

Requirement Specification and Frequency Acceptance Criteria

Sect. 8.4 Sample Holding Time 14 days for analytes with appropriate preservation and 

storage as described in Sects. 8.1-8.3. 

Sample results are valid only if samples are 

extracted within sample hold time.

Sect. 8.4 Extract Holding Time 14 days stored at -5 °C and protected from light Sample results are valid only if extracts are 

analyzed within extract hold time.

Sect. 9.3.1 Laboratory Reagent Blank 

(LRB)

One LRB with each extraction batch of up to 20 Field 

Samples.

Demonstrate that the method analyte concentration 

is ≤

1

/3 the MRL, and confirm that possible 

interferences do not prevent quantification. If the 

background concentration exceeds

1

/3 the MRL, 

results for the extraction batch are invalid.

Sect. 9.3.3 Laboratory Fortified 

Blank (LFB)

One LFB is required for each extraction batch of up to 

20 Field Samples. Rotate the fortified concentrations 

between low, medium, and high amounts.

Results of LFB analyses at medium and high 

fortifications must be ± 30% of the true value for all 

analytes except o-toluidine which may be 50-130%

of the true value. Results of the low-level LFB must 

be ± 50% of the true value.

Sect. 9.3.5 Internal Standard (IS) Compare IS area to the mean IS area from the analysis 

of each CAL in the initial calibration and the area in the 

most recent CCC.

Peak area counts for all ISs in all injections must be 

within ± 50% of their mean peak area calculated 

during the initial calibration. Peak areas of ISs must 

also be ± 30% from the most recent CCC. If the ISs

do not meet these criteria, target analyte results are 

invalid. Consult Sect. 9.3.5 for further information.

Sect. 9.3.6 Surrogate (SUR)

Standards

The SUR standards are added to all calibration standards 

and samples, including QC samples prior to extraction. 

Calculate SUR recoveries.

Quinoline-d7 must be 70-130% of the true value and 

o-toluidine-d9 must be 50-130% of the true value. If 

any SUR fails this criterion, report all results for 

sample as suspect/SUR recovery.

Sect. 9.3.7 Laboratory Fortified 

Sample Matrix (LFSM)

Analyze one LFSM per extraction batch (of up to 20 

Field Samples) fortified with the method analytes at a 

concentration greater than or equal to the native 

concentration. Calculate LFSM recoveries.

See Sect. 9.3.7.3 for instructions on the 

interpretation of LFSM results.
 

530-49 

Table 11. Ongoing Quality Control (QC) Requirements (Summary) (Continued) 

Sect. 9.3.8 Laboratory Fortified 

Sample Matrix Duplicate 

(LFSMD) or Field 

Duplicates (FD)

Extract and analyze at least one FD or LFSMD with 

each extraction batch of up to 20 Field Samples. An

LFSMD may be substituted for a FD when the 

frequency of detects for analytes of interest are low. 

Calculate RPDs.

Method analyte RPDs for the LFSMD or FD should 

be ≤30% at mid and high levels of fortification and 

≤50% at concentrations within two times the MRL. 

Failure to meet this criterion may indicate a matrix 

effect.

Sect. 9.3.9 Quality Control Sample 

(QCS)

Analyze a QCS during the IDC, and each time new CAL 

solutions or PDSs are prepared. A QCS must be 

analyzed at least quarterly.

Results must be ±30% of the expected value.

Sect. 10.2 Initial Calibration Use the IS calibration technique to generate a linear or 

quadratic calibration curve for each analyte. A minimum 

of six standards should be used for a calibration range of 

two orders of magnitude. Suggested concentrations can 

be found in Sect. 7.2.4. Check the calibration curve 

against the acceptance criteria in Sect. 10.2.5.

When each calibration standard is calculated as an 

unknown using the calibration curve, the result 

should be ± 30% of the true value for all except the 

lowest standard (<MRL), which should be ± 50% of 

the true value. If this criterion is not met, reanalyze 

CALs, select a different method of calibration or 

recalibrate over a shorter range.

Sects. 10.1 

and 10.2.1

MS Tune Check Analyze DFTPP to verify the MS tune after instrument 

maintenance and each time the instrument is mass 

calibrated. The MS tune must also be verified prior to 

analyzing CAL stds and establishing calibration curves 

for method analytes.

Acceptance criteria are given in Table 2. 

Sect. 10.3 Continuing Calibration 

Check (CCC)

Verify initial calibration by analyzing a calibration 

standard at the beginning of each analysis batch prior to

analyzing samples, after every10 Field Samples, and 

after the last sample of each analysis batch. The first 

CCC daily must be at or below the MRL. Subsequent 

CCCs alternate between the remaining calibration 

levels.

Low CCC – at or below the MRL concentration

Mid CCC – near midpoint in the initial calibration curve

High CCC – near the highest calibration standard.

Low: ±50% of true value

Mid: ±30% of true value

High: ±30% of true value

Note: Table 11 is intended as an abbreviated summary of QC requirements provided as a convenience to the method user. Because the information has been 

abbreviated to fit the table format, there may be issues that need additional clarification, or areas where important additional information from the method text is 

needed. In all cases, the full text of Sects. 8-10 in the method supersedes any missing or conflicting information in this table.
 

530-50 

Figure 1. Example full scan chromatogram of a calibration standard (concentration of 5 ng/μL injected for all analytes). Peak 

identification numbers correspond to those in the legend and to those in Table 1. 
 

530-51 

Figure 2. Results of Aqueous Holding Time Study (Sect. 13.3) 
 

530-52 

Figure 3. Results of Extract Holding Time Study (Sect. 13.4)