EPA Office of Water May 20, 2010 Engineering & Analysis Division

Page No.: 1 of 25 

## FGD ICP/MS SOP: Inductively Co upled Plasma Mass Spectrometry for Trace Element Analysis in Flue Gas Desulfurization Wastewaters

1.0 Scope and Application

1.1 This document describes procedures used to measure elements in Flue Gas Desulfurization (FGD) wastewaters. Inductively coupled plasma-mass spectrometry (ICP/MS), as described in EPA Methods 200.8 and 1638, was used with a collision cell to mitigate the effects of interferences in the samples. These procedures are intended for use by analysts experienced with applying ICP/MS to complex wastewater samples.

1.2 These procedures are applicable to the analysis of acid digested FGD wastewater, and have been evaluated for the analysis of 13 elements of interest. These are Al, As, Cd, Cr, Cu, Pb, Mn, Ni, Se, Ag, Tl, V and Zn. Additional elements may be included provided that the performance criteria presented in Sections 9 and 12 are met.

1.3 Flue Gas Desulfurization wastewaters frequently have very high levels of calcium, sodium, magnesium, manganese, chloride and sulfate (up to thousands of ppm). The use of instrument configurations and/or accessories designed to accommodate samples with high dissolved solids levels is highly recommended. 2.0 Summary

2.1 Aqueous samples, digestates, or leachates are nebulized into a spray chamber where a stream of argon carries the sample aerosol through the quartz torch and injects it into an RF plasma. There the sample is decomposed and desolvated.

2.2 The ions produced are entrained in the plasma gas and by means of a watercooled, differentially pumped interface, introduced into a high-vacuum chamber that houses a quadrupole mass spectrometer capable of providing a resolution better than or equal to 0.9 amu peak width at 10% of the peak height. The ions are separated according to their mass-to-charge ratio and measured with a detector, such as an electron multiplier.

2.3 A collision/reaction cell utilizing He and (optionally) H 2 gases is used to remove molecular interferences.

2.4 Interferences not eliminated by the collision/reaction cell must be assessed and valid corrections applied, or the data flagged to indicate problems. Interference correction must include compensation for interferences not removed by the collision / reaction cell. Recommended elemental equations are listed in Attachment 1. Use of the internal standard technique is required to compensate for suppressions and enhancements caused by sample matrices.

3.0 Definitions

3.1 Batch – A group of samples which behave similarly with respect to the sampling or the testing procedures being employed and which are processed as a unit. For QC purposes, if the number of samples in a group is greater than 20, then each group of 20 samples or less will all be handled as a separate batchEPA Office of Water May 20, 2010 Engineering & Analysis Division

Page No.: 2 of 25 3.2 Dissolved Metals - Those elements which pass through a 0.45- μ m membrane filter (sample is acidified after filtration).
3.3 Suspended Metals - Those elements which are retained by a 0.45- μ m membrane filter.

3.4 Total Recoverable Metals - The concentration determined on an unfiltered sample following treatment with hot, diluted mineral acids, as described in this procedure 3.5 Instrument Detection Limit (IDL) - See Section 12.2 3.6 Sensitivity - The slope of the analytical curve (i.e., the functional relationship between raw instrument signal and the concentration). 3.7 Tuning Solution - This is a multi-element solution containing analytes which are representative of the entire mass range capable of being scanned by the instrument. It is used to optimize the sensitivity of the instrument and to verify the mass resolution meets method criteria. 3.8 Initial Calibration Verification / Quality Control Standard (ICV/QCS) - A multielement standard of known concentrations prepared to verify instrumentcalibration. This solution must be an independent standard prepared near the midpoint of the calibration curve, and at a concentration other than that used for instrument calibration. 3.9 Continuing Calibration Verification (CCV). - A multi-element standard of known concentrations prepared to monitor and verify the instrument daily continuing performance. 3.10 Laboratory Control Sample / Laboratory Fortified Blank (LCS/LFB) - A multielement standard of known concentrations that is carried through the entire sample preparation and analysis procedure. This solution is used to verify method performance in an ideal sample matrix. 3.11 Reagent Blank - High purity (> 18 megohm-cm) water containing the same acid matrix as the calibration standards that is carried through the entire digestion process. The reagent blank is used to determine the concentrations of trace metals in the reagents used to prepare and analyze the samples.

3.12 Calibration Blank - High purity (> 18 megohm- cm) water acidified with the same acid concentrations present in the standards and samples. Also referred to as the Initial Calibration Blank (ICB) and Continuing Calibration Blank (CCB). 3.13 Method Detection Limit (MDL) – Refers to the instructions in Appendix B to 40 CFR Part 136. Also see Section 12.1 of this document. The MDL is determined from analysis of a sample in a given matrix containing the analyte.

3.14 Individual FGD Interference Check solutions – Single element solutions at concentrations similar to those found in flue gas desulfurization wastewaters. 3.15 Synthetic FGD wastewater – A mixed solution of elements at typical concentrations found in flue gas desulfurization wastewaters.EPA Office of Water May 20, 2010 Engineering & Analysis Division

Page No.: 3 of 25 4.0 Interferences

4.1 Isobaric Interferences Isobaric interferences in the ICP/MS are caused by isotopes of different elements forming ions with the same nominal mass-to-charge ratio (m/z). The recommended ions used for the elements in this procedure do not have elemental isobaric interferences, except for a very small interference from krypton on 78 Se, which can be avoided by using argon free of krypton.

4.2 Isobaric Molecular

• Isobaric molecular interferences are caused by ions consisting of more than one atom. These molecular interferences are minimized by use of the collision cell utilizing He and/or H 2 gases. Common examples are potential interferences from 40 Ar 35 Cl or 40 Ca 35 Cl on 75 As, or 35 Cl 16 O on 51 V, or 40 Ar 12 C

on 52 Cr. Collision cell interference removal works both by causing the interfering molecular ion to dissociate and by reducing the kinetic energy of the ion. The latter is termed Kinetic Energy Discrimination (KED), and is the primary mechanism for interference removal. Polyatomic ions are larger than elemental ions and so collide with the helium atoms in the collision cell more frequently than the smaller elemental ions. Each collision reduces the energy of the ion, so the molecular ions lose energy more quickly. At the end of the collision cell there is a positive voltage plate that prevents passage of the now low energy molecular ions. Since the molecular ions do not reach the detector, the interference is eliminated. 4.3 Doubly Charged Ion Interferences Doubly charged elemental ions are possible in cases where the second ionization potential of the element is significantly below the fist ionization potential for argon (15.7eV). If a doubly charged ion is formed, it will cause a response at half of its elemental mass, potentially causing an interference. Fortunately, most elements have high enough second ionization potentials that formation of doubly charged ions is not an issue. For the target analytes in this procedure, a significant potential for interference is from 150 Nd and 150 Dy (potential interference on 75 As and from
156 Gd (potential interference on 78 Se). To check for these potential interferences, monitor the response for mass 150 and 156. If the cps for these masses is > 5 times the cps for the quantitation limit for arsenic (in the case of mass 150) or selenium (in the case of mass 156) an interference is possible. In this case analyze a 100ppb standard of Nd and Dy (if mass 150 is observed) or Gd (if mass 156 is observed) and measure the response at 150 and 75 (or 156 and 78). This ratio can then be used to create an interference correction equation. For example, if the response for a 100ppb Gd standard at mass 156 is 10,000 cps, and the observed response for the same standard at mass 78 is 1,000 counts, then the equation for 78 Se would be:

78 Se = 78 Se – ( 156 Gd/10) 4.4 Physical Interferences

• Physical interferences are associated with the transport and nebulization process. Internal standards are used to compensate for these types of interferences.

• Internal standards should be added at a level to give approximately 50,000 - 800,000 counts of raw signal intensity. The mass of the internal standardEPA Office of Water May 20, 2010 Engineering & Analysis Division

Page No.: 4 of 25 should ideally be within 50 amu of the mass of the measured analyte. Consideration should also be given to matching internal standards to analytes with similar ionization potentials.

• Matrix effects are monitored by comparing the internal standard intensity in the sample to the internal standard intensity of the calibration blank. The internal standards must be between 60% and 125% of the calibration blank. If they are outside this window the sample is diluted by a factor of 2 (1:1) and is reanalyzed.

• Memory effects are dependent on the relative concentration differences between samples and/or standards which are analyzed sequentially. The rinse period between samples must be long enough to eliminate significant memory interference (see section 10.3.6). 5.0 Safety

This procedure may involve hazardous material, operations and equipment. This procedure does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of the method to follow appropriate safety, waste disposal and health practices under the assumption that all samples and reagents are potentially hazardous. Safety glasses, gloves, lab coats and closed-toe, nonabsorbent shoes are required.

5.1 Specific Safety Concerns or Requirements

5.1.1 Eye protection that satisfies ANSI Z87.1, laboratory coat, and nonpowdered nitrile or latex gloves must be worn while handling samples, standards, solvents, and reagents. Disposable gloves thathave been contaminated must be removed and discarded; nondisposable gloves must be cleaned immediately.

5.1.2 The ICP plasma emits strong UV light and is harmful to vision. All analysts must avoid looking directly at the plasma. The RF Generator produces strong radio frequency waves, most of which are unshielded. People with pacemakers should not go near the instrument while in operation.

5.2 Primary Materials Used The following is a list of the materials used in this method, which have a serious or significant hazard rating. Note: This list does not include all materials used in the method. The table contains a summary of the primary hazards listed in the MSDS for each of the materials listed in the table.EPA Office of Water May 20, 2010 Engineering & Analysis Division

Page No.: 5 of 25 Material (1) Hazards Exposure Limit (2) Signs and Symptoms of Exposure

Nitric Acid Corrosive Oxidizer Poison 2 ppmTWA4 ppmSTEL Nitric acid is extremely hazardou s; it is corrosive, reactive, an oxidizer, and a poison. I nhalation of vapors can cause breathing difficulties and lead to pneumonia and pulmonary edema, which may be fatal. Other symptoms may include coughing, choking, and irritation of the nose, throat, and respiratory tract. Can cause redness, pain, and severe skin burns. Concentrated solutions cause deep ulcers and stain skin a yellow or yellow-brown color. Vapors are irritating and may cause damage to the eyes. Contact may cause severe burns and permanent eye damage.

Material (1) Hazards Exposure Limit (2) Signs and Symptoms of Exposure
Hydrochloric Acid Corrosive Poison 5 ppmCeiling Inhalation of vapors can cause coughing, choking, inflammation of the nose, thr oat, and upper respiratory tract, and in severe cases, pulmonary edema, circulatory failure, and death. Can cause redness, pain, and severe skin burns. Vapors are irritating and may cause damage to the eyes. Contact may cause severe burns and permanent eye damage. 1 – Always add acid to water to prevent violent reactions. 2 – Exposure limit refers to the OSHA regulatory exposure limit.

6.0 Equipment and Supplies

6.1 Instrumentation

• Inductively Coupled Plasma Mass Spectrometer (ICP/MS) capable of providing resolution, less than or equal to 0.9 amu at 10% peak height from 6-253 amu and 1.0 amu at 5% peak height from 6-253 amu with a data system that allows corrections for isobaric interferences and the application of the internal standard technique. The ICP/MS must be equipped with a collisio n cell for the removal of molecular interferences. This procedure was developed using an Agilent 7500 or 7700 instrument equipped with a high matrix interface. The interface extends the amounts of total dissolved solids that may be measured into the percent concentration range. Any collision cell instrumentation that meets the specifications in this procedure may be used.

• A discrete sample introduction system enables the use of only the exact amount of sample volume required for data acquisition.

• Accessories and configuration that are designed to accommodate samples with high levels of dissolved solids should be used.

• This sampling system results in less matrix being deposited in the system during analysis and minimizes the rinse times normally needed for difficult matrices.

• Autosampler with autosampler tubes.

• Appropriate water cooling device.

• Block digester with tubes.

6.2 Supplies

• Argon gas: High purity grade (99.99%).EPA Office of Water May 20, 2010 Engineering & Analysis Division

Page No.: 6 of 25 • Helium gas: High purity grade (99.99%).

• Hydrogen gas: High purity grade (99.99%).

• Calibrated automatic pipettes or Class A glass volumetric pipettes.

7.0 Reagents and Standards 7.1 Storage and Shelf-Life

7.1.1 All standards must be stored in glass, FEP fluorocarbon or previously unused polyethylene or polypropylene bottles. Standards stored at concentrations as received from the vendor and mid-level dilutions must be replaced prior to the expiration date assigned by the vendor. If no expiration date is provided, the stocks and mid-level standards may be stored for up to one year. They must be replaced sooner if verification from an independent source indicates a problem (See section 10.3.5 for initial calibration verification acceptance criteria).

7.1.2 Working standards, i.e., all standards at concentrations ready to analyze on the ICP/MS (all except tuning mixes, ICSA and ICSAB mixes, which are received at ready-to-use concentrations), are prepared fresh daily.

7.2 Standards 7.2.1 Tuning Solution, 10 ppb The tuning solution stock is purchased as a custom multi-element mix. The concentrations of the constituents are shown in Attachment 5. Prepare the Tuning Solution as detailed below.

• Obtain a clean 100 mL volumetric flask.

• Place 50 mL of reagent water and 2 mL of conc. HNO 3 and 0.5 mL of conc. HCl in the flask.

• Swirl to mix.

• Pipet 0.1mL of the Tuning Solution Stock into the flask

• Dilute to volume with reagent water. Stopper and mix. 7.2.2 PA Tuning Solution The dual detector solution may be commercially purchased as a custom multi-element mix. Prepare the PA Tuning Solution as detailed below.

• Add approximately 50 mL of the 2% HNO 3 / 0.5% HCl to a 100 mL volumetric flask.

• Prepare at a concentration recommended by the instrument manufacturer.

7.2.3 Calibration Standards Stock calibration standards are purchased as custom multi-element mixes or as single element solutions. Each day of analysis, the standards are diluted to working levels using 2% nitric acid and 0.5% HCl acid matrix. Suggested concentrations are given in Attachment 8, but the laboratory may adjust calibration standard concentrations as appropriateEPA Office of Water May 20, 2010 Engineering & Analysis Division

Page No.: 7 of 25 for the instrument and samples. At a minimum, a 3 point curve must be used.

7.2.4 Individual FGD Interference check solutions.

7.2.4.1 All individual FGD interference check solutions should be made up in the same acid matrix as the calibration standards.

7.2.4.2 Chloride, 10,000 mg/L

7.2.4.3 Calcium, 5,000 mg/L

7.2.4.4 Sulfate, 4,000 mg/L

7.2.4.5 Magnesium, 3,000 mg/L

7.2.4.6 Sodium, 2,000 mg/L

7.2.4.7 Boron 500 mg/L

7.2.4.8 Iron 500 mg/L

7.2.4.9 Nitrate 250 mg/L

7.2.4.10 Manganese 200 mg/L

7.2.4.11 Bromide 100 mg/L

7.2.4.12 Fluoride 100 mg/L

7.2.4.13 Selenium 20 mg/L

7.2.4.14 Vanadium 10 mg/L

7.2.4.15 Zinc 2 mg/L

7.2.4.16 Chromium 1 mg/L

7.2.4.17 Copper 1 mg/L

7.2.5 Mixed Interference Check Solution (Synthetic FGD Wastewater)

7.2.5.1 Chloride, 5,000 mg/L

7.2.5.2 Calcium, 2,000 mg/L

7.2.5.3 Magnesium, 1,000 mg/L

7.2.5.4 Sulfate, 2,000 mg/L

7.2.5.5 Sodium, 1,000 mg/L

7.2.5.6 Butanol, 2000ppm

7.2.6 Initial Calibration Verification (ICV) Standard

The ICV stock is from a source different than the source for the calibration standards. Each day of analysis, the ICV standard is prepared in 2% HNO 3 and 0.5 % HCl acid to the concentrations shown in Attachment 8.EPA Office of Water May 20, 2010 Engineering & Analysis Division

Page No.: 8 of 25 7.2.7 Continuing Calibration Verification (CCV) Standard The CCV is prepared from the same source as the calibration standards. The CCV standards are prepared fresh each day of analysis in 2% HNO 3 /0.5% HCl. The concentrations are shown in Attachment 8. Prepare the Working CCV as detailed below.

• Dilute by 2X a known volume of the Working Calibration Standard in the 2% HNO 3 / 0.5% HCl acid matrix. 7.2.8 Spiking Stock Solution The spike stock solution is prepared from the same stocks as the calibration standards using the 2% HNO 3 / 0.5% HCl acid matrix. Spike concentrations are listed in Attachment 8. 7.3 Reagents 7.3.1 Reagent Water - ASTM Type I or equivalent for the elements of interest, generated using an ion-exchange water polishing system capable of achieving 18.0 megohm-cm.

7.3.2 Blank Matrix 2% HNO 3 and 0.5% HCl.

8.0 Sample Collection, Preservation, Shipment and Storage Sample container, preservation techniques and holding times may vary and are dependent on sample matrix, method of choice, regulatory compliance, and/or specific contract or client requests. Listed below are the holding times and the references that include preservation requirements.

Matrix Sample Container Min. Sample Size Preservation Holding Time Reference

Waters HDPE 50 mLs HNO 3 , pH < 2 180 Days 40 CFR Part 136.3

Soils Glass or HDPE 4 oz Cool 4 + 2 o C 180 Days N/A

9.0 Quality Control

9.1 Quality control requirements are also summarized in Attachment 7.

9.2 Ongoing data quality checks are compared with established performance criteria to determine if the results of analyses meet the performance characteristics of the method. Any QC result that fails to meet control criteria must be documented.

9.3 Individual interference check solutions The individual interference check solutions listed in section 7.2.6 are analyzed prior to initiating sample analysis, and at least once per quarter while FGD wastewaters are being analyzed, and after any major changes to instrument operating conditions. Concentrations of target elements observed should be less than their reporting limits. In some cases it may not be possible to obtain interference check solutions that are completely free of contamination. In this case, results up to 5X the reporting limit are acceptable if it is possible to demonstrate that the isotopic ratios correspond to natural abundances. For example, the naturalEPA Office of Water May 20, 2010 Engineering & Analysis Division

Page No.: 9 of 25 abundances of zinc isotopes are Zn 64 48.6%; Zn 66 27.9%; Zn 67 4.1%; Zn 68 18.8%; Zn 70 0.6%. The measured ratios are not expected to be exact, especially for low abundance isotopes, and some isotope may be masked by other elements in the solution, (for example Zn 70 in the above example will be masked by Ge 70 ) but it must be possible to explain the observed ratios. Because Arsenic, Manganese and Aluminum are monoisotopic, this demonstration is not possible and the level of interference observed must be less than the reporting limit

. 9.4 Synthetic FGD interference check solution The synthetic FGD matrix solution listed in section 7.2.7 is analyzed prior to initiating sample analysis, and at least once per day (immediately after calibration) while FGD wastewaters are being analyzed, and after any major changes to instrument operating conditions. Internal standard recovery must meet method criteria (Section 9.9) and concentrations of target elements observed should be less than their reporting limits. In some cases it may not be possible to obtain interference check solutions that are completely free of contamination. In this case, results up to 5X the reporting limit are acceptable if it is possible to demonstrate that the isotopic ratios correspond to natural abundances. For example, the natural abundances of zinc isotopes are Zn 64 48.6%; Zn 66 27.9%; Zn 67 4.1%; Zn 68 18.8%; Zn 70 0.6%. The measured ratios are not expected to be exact, and some isotopes may be masked by other elements in the solution, (for example Zn 70 in the above example will be masked by Ge 70 ) but it must be possible to explain the observed ratios. Because Arsenic, Manganese and Aluminum are monoisotopic, this demonstration is not possible, and the level of interference observed must be less than the reporting limit. If the Synthetic FGD solution has to be diluted in order to analyze it effectively on the ICP/MS, then all samples and QC (including the MDL replicates) must be diluted by at least the same factor.

9.4.1 Laboratory fortified Synthetic FGD solution The synthetic FGD solution is spiked with 40ppb of each of the target elements (400ppb for zinc and 4000ppb for aluminum) and analyzed once per day, immediately after the synthetic FGD check in section 9.4. All target elements must be recovered within 70-130% of the true value. If the Laboratory Fortified Synthetic FGD solution has to be diluted in order to analyze it effectively on the ICP/MS, then all samples and QC (including the MDL replicates) must be diluted by at least the same factor. 9.5 Linear range determination The linear range for each element is determined prior to initiating sample analysis and at least once per year thereafter. The linear range must also be determined subsequent to changes that will have a major effect on instrument sensitivity, such as changing the detector. The linear range is established using a single element standard at the desired linear range. The result of the analysis must be within 10% of the true value. 9.6 Method Blank / Laboratory Reagent Blank (MB/LRB) The method blank consists of reagent water that has been processed in the same manner as the samples. One method blank must be processed with each preparation batch. Acceptance Criteria: Method blank results are acceptable if the concentration for each analyte of interest is less than the reporting limit.EPA Office of Water May 20, 2010 Engineering & Analysis Division

Page No.: 10 of 25 Corrective Action: If the method blank does not meet the acceptance criteria, the source of contamination should be investigated to determine if the problem can be minimized or eliminated. Samples associated with the contaminated blank shall be reprocessed for analysis, or under the following circumstances, may be reported as qualified (qualifier flags or narrative comments must be included on report):

• The same analyte was not detected in the associated samples;

• The method blank concentration is less than 1/10 of the measured concentration of any sample in the batch;

• The method blank concentration is less than 1/10 the specified regulatory limit; or

• The analyte is a common laboratory contaminant (copper, iron, lead, calcium, magnesium, potassium, sodium, or zinc) less than 2 times the RL. Note that some programs do not recognize common lab contaminants. If the above criteria are not met and reanalysis is not possible, then the sample data must be qualified. This anomaly must be addressed in the project narrative and the client must be notified. 9.7 Laboratory Control Sample / Laboratory Fortified Blank (LCS/LFB) The LCS consists of reagent water that is spiked with the analytes of interest as summarized in Attachment 8. One LCS must be processed (digestion and analysis) for each preparation batch. Acceptance Criteria: LCS control limits are based on three standard deviations of past laboratory results. These limits are not to exceed 85-115% recovery. The control limits are maintained in a LIMS or other appropriate system.

Corrective Action: If the LCS % recovery falls outside of the control limits for any analyte, that analyte is judged to be out of control. All associated samples must be reprocessed for analysis. One possible exception is a recovery for a given element above the upper control limit with no detection for the same element in the samples. 9.8 Matrix Spike / Matrix Spike Duplicate / Laboratory Fortified Sample Matrix / Laboratory Fortified Matrix Duplicate (MS/MSD/LFSM/LFMD) MS is prepared by taking a second aliquot of a selected sample and spiking it with the analytes of interest as summarized in Attachment 8. An MSD is prepared by taking a third aliquot of a selected sample and spiking it with the analytes of interest as summarized in Attachment 8. The MS and MSD are processed in the same manner as the samples. One MS/MSD pair must be processed every 10 samples. Acceptance Criteria: Control limits are based on three standard deviations of past laboratory results. These limits are not to exceed 70- 130% recovery, and 20% relative percent differenceEPA Office of Water May 20, 2010 Engineering & Analysis Division

Page No.: 11 of 25 (RPD). The control limits are maintained in the LIMS system. If the sample concentration for a specific analyte in the sample selected for spiking is greater than the concentration added by the spike, then recovery accuracy will be reduced. In this case a dilution test may be performed. A 1:5 dilution should agree within 20% of the original determination. If not, a physical or chemical interference is suspected, and must be discussed in the sample narrative.

Corrective Action: If MS/MSD results and any applicable dilution tests do not meet the acceptance criteria and all other quality control criteria have been met, then a matrix interference is suspected. Failed matrix spikes are flagged, and are discussed in the final report case narrative. 9.9 Internal Standards Evaluation for Samples The internal standards in samples must be between 60 and 125% of the intensity in the calibration blank. If the sample intensities fall outside this range, the calibration blank is reanalyzed to confirm the instrument has not drifted out of control. If the criteria is met, the sample is diluted by a factor of 2 (1:1) and reanalyzed. IS limits and corrective actions for standards and blanks are described in Section 10.

10.0 Procedure

10.1 One-time procedural variations are allowed only if deemed necessary in the professional judgment of the supervisor to accommodate variation in sample matrix, radioactivity, chemistry, sample size, or other parameters. Any variation in procedure shall be completely documented. Any unauthorized deviations from this procedure must also be documented as a nonconformance, with a cause and corrective action described. 10.2 Sample Preparation

10.2.1 EPA Method 1638 was used as the reference for the digestion of the samples in which Section 12.2.8 describes Closed Vessel digestion.

10.2.2 Transfer a 50mL (+/- 0.5mL) aliquot from a well mixed acid preserved sample to a 50mL digestion tube.

10.2.3 Add 0.5mL of concentrated nitric acid and 0.25 mL hydrochloric acid.

10.2.4 Spike the LCS and MS/MSD samples per spiking protocols.

10.2.5 The total volume of the solution in the tube is now greater than 50 mLs. The final volume will be 50 ml following the procedure to eliminate the discrepancy in the initial and final volumes.

10.2.6 Tightly cap each digestion vessel.

10.2.7 Place the digestion tube into a block digester adjusted to achieve a temperature of approximately 85 o C.

10.2.8 Heat for 2 hours after 85 o C is obtained.

10.2.9 Remove from the block and allow to cool.EPA Office of Water May 20, 2010 Engineering & Analysis Division

Page No.: 12 of 25 10.3 Calibration 10.3.1 Instrument Start Up Set up the instrument according to manufacturer’s operating instructions. Allow the instrument to become thermally stable for at least 30 minutes before tuning. 10.3.2 Instrument Tuning / Mass Calibration Tune the instrument with a solution c ontaining elements representing all of the mass regions of interest. The relative standard deviations must be less than 5% for a minimum of 4 integrations of the solution. Mass calibration and resolution checks using the tuning solution must be completed at the beginning of every day.

Mass Calibration Check – The mass calibration results must be within 0.1 amu from the true value. If this criterion is not met, the mass calibration must be adjusted before running samples.

Mass Resolution Check - The resolution must be verified to be less than 0.9 amu full width at 10% peak height.

10.3.3 Mass 75 interference check The counts per second for mass 75 must be less than 10 when the blank matrix (2% nitric acid / 0.5% hydrochloric acid) is infused (using the collision gas mode used for arsenic). CPS > 10 under these conditions indicates that the collision cell is not effectively removing molecular interferences (in this case Ar 40 Cl 35 ).

10.3.4 Initial Calibration The ICP/MS is calibrated each day of operation using a blank and at least 3 standards (see Section 7.2.3). Report the average of at least three integrations. The validity of the calibration is determined by the subsequent calibration verifications, which are performed at concentrations as described in the next sections. 10.3.5 Second-Source Initial Calibration Verification (ICV) A 40 μ g/L / 4,000 ug/L ICV standard (see Section 7.2.8) is analyzed immediately after the initial calibration. This is a standard obtained from a different vendor than the standard used for calibration. This analysis also satisfies the Method 200.8 requirement for a Quality Check Standard (QCS). Acceptance Criteria: The ICV recovery must be within 90-110%. Additionally, the internal standard recoveries for 200.8 must fall between 60 and 125% of true values. The ICV can be reanalyzed, but must be successful twice in succession or corrective action must be taken.

Corrective Action: If the ICV results are outside of the acceptance limits, investigate the accuracy of the standards, correct as necessary, and recalibrate.EPA Office of Water May 20, 2010 Engineering & Analysis Division

Page No.: 13 of 25 10.3.6 Calibration Blank Checks for the memory effects described at Section 4.4 may be accomplished by analysis of an initial calibration blank (ICB) after the ICV. Continuing calibration blanks (CCBs) are analyzed after each continuing calibration verification. Acceptance Criteria: Results for the calibration blanks must be less than the RL.

Corrective Action: If the calibration blank exceeds acceptance limits, then the possibility of instrument contamination should be examined, particularly the possibility of carry-over from high level samples. The blank can be reanalyzed, and if successful, analysis can continue. However, samples tested after high-level samples should be retested. If the reanalysis is not successful, then the analysis should be terminated. After the problem is corrected, recalibrate and reanalyze all samples tested since the last acceptable CCB. 10.3.7 Reporting Limit (RL) Verification Standard An independent standard is analyzed after the ICV to monitor the lab’s ability to produce reliable results at RL-level concentrations. The RL verification standard is analyzed after the daily ICB. Acceptance Criteria: For project reporting limits at or above two times the MDL, the results should be within 50% of the expected value. Some programs may require tighter control, in which case the RLs will need to be three or more times the MDL concentration.

Corrective Action: If the RL verification fails to meet acceptance limits, data for the associated samples must be assessed. For example, if the results are high, consider blank contamination, and if the results are low, consider MDL verifications. At a minimum, sample results must be qualified in the final report. 10.3.8 Continuing Calibration Verification (CCV) Standard A 50 μ g/L CCV standard is analyzed after every set of ten samples and at the end of the analytical sequence. Acceptance Criteria: The CCV recovery must be within 85-115%. In addition, the IS recovery must be within 60- 125%. If CCV results are not within these limits, the CCV can be reanalyzed, but it must be successful twice in succession or further corrective action must be taken.

Corrective Action: If the CCV fails acceptance criteria, then the analysis should be terminated. Recalibrate and reanalyze all samples tested since the last acceptable CCB.EPA Office of Water May 20, 2010 Engineering & Analysis Division

Page No.: 14 of 25 10.4 Sample Analysis

10.4.1 Report the average of at least three integrations for all field and QC samples analyzed.

10.4.2 Flush the system with the rinse blank for at least 30 seconds between samples and standards during the analytical run. Evaluate the effectiveness of this time and increase the flush time, if needed.

10.4.3 It may be valuable to monitor additional isotopes for elements that are potentially susceptible to interferences. In particular, monitoring additional isotopes for selenium may help data analysis.

10.4.4 Dilute and reanalyze samples that are more concentrated than the highest calibration standard for an analyte or specific isotope of interest. No analyte may be reported from an analysis of a diluted sample in which the analyte concentration is less than 5 times the RL. The analytical run sequence should be performed as follows to meet all quality control criteria:
Instrument initialization Warm-up Tune instrument Perform mass calibration Perform resolution check Validate tuning criteria Calibration blank Calibration standard 1 Calibration standard 2 Calibration standard 3 ICV ICB RL verification standard CCV CCB 10 Samples (which can include all sample types) CCV CCB

11.0 Calculations / Data Reduction

11.1 LCS percent recoveries are calculated according to the equation:

11.2 ICV percent recoveries are calculated according to the equation:



### % 100 Value True ICV Value Found ICV % × ⎟ ⎠ ⎞ ⎜ ⎝ ⎛

= R % 100 Value True LCS Value Found LRB

- Value Found LCS % × ⎟ ⎠ ⎞ ⎜ ⎝ ⎛

= REPA Office of Water May 20, 2010 Engineering & Analysis Division

Page No.: 15 of 25 11.3 CCV percent recoveries are calculated according to the equation:

11.4 Matrix Spike Recoveries are calculated according to the following equation:

Where: SSR = Spike Sample Result SR = Sample Result SA = Spike Added

NOTE: When the sample concentration is less than the detection limit, use SR = 0 for the purpose of calculating %R.

11.5 The relative percent difference (RPD) between sample duplicates is calculated according to the following equation:

Where: DU1 = Sample result DU2 = Sample duplicate result

11.6 The final concentration for an aqueous sample is calculated as follows:



### 2 1 g/L) ( Result V D V C × ×

= μ

Where: C = Concentration from instrument readout, ppb
D = Instrument dilution factor V1 = Final volume in liters after sample preparation V2 = Initial volume of sample digested in liters 

### % 100 Value True CCV Value Found CCV % × ⎟ ⎠ ⎞ ⎜ ⎝ ⎛

= R

% 100 SA SR

- SSR % × ⎟ ⎠ ⎞ ⎜ ⎝ ⎛

= R



# ( ) 100 2 1 2 1 / 2 1 /
× ⎥ ⎥ ⎦ ⎤
⎢ ⎢ ⎣ ⎡

+ −

= DU DU DU DU RPDEPA Office of Water May 20, 2010 Engineering & Analysis Division

Page No.: 16 of 25 12.0 Method Performance

12.1 Method Detection Limit Study (MDL) An initial method detection limit study must be performed on each instrument before samples can be analyzed. MDL studies are conducted annually as follows:

• Prepare seven samples at three to five times the estimated MDL concentration. The MDL samples are prepared in the Synthetic FGD wastewater matrix and in reagent water.

• Prepare and analyze the MDL standards as described in Section 10.

• Calculate the average concentration found in μg/L, and the standard deviation of the concentration(s) in μg/L, for each analyte.

• The MDL is calculated as Students t for the 99 th percentile times the standard deviation of the MDL replicate results, following the procedure at 40CFR Part 136, Appendix B. NOTE1: Perform the MDL study in the synthetic FGD wastewater matrix. Spiking this matrix provides detection limits that are better matched to the complex matrix typical of FGD wastewater. These limits can be significantly higher than those obtained in a reagent water matrix. In some cases (zinc in particular), the level of contamination in the synthetic FGD solution may be high enough to result in somewhat elevated MDLs.

NOTE2: An FGD-MDL may be less than the MDL observed in method blanks. If this occurs frequently, the FGD-MDL should be elevated to the mean of the method blanks plus the Student t factor times the standard deviation of the method blanks.

12.2 Instrument Detection Limit Study Instrument detection limit (IDL) studies are conducted quarterly for each instrument and each mass used for analysis.

• Prepare ten blanks.

• Analyze the IDL blanks on three non-consecutive days.

• The IDL is equal to three times the standard deviation of the blank results.

12.3 Demonstration of Capabilities All personnel are required to perform an initial demonstration of proficiency (IDOC) on the instrument they will be using for analysis prior to testing samples. On-going proficiency must be demonstrated annually. IDOCs and on-going proficiency demonstrations are conducted as follows. Four aliquots of the ICV are analyzed using the same instrumental conditions and procedures used to analyze samples. The analyst must employ ICV’s from four distinct analytical sequences. Using these four ICV’s demonstrates the analyst’s ability to optimize and calibrate the instrument and to prepare analytical solutions. Calculate the average recovery and standard deviation of the recovery for each analyte of interest.EPA Office of Water May 20, 2010 Engineering & Analysis Division

Page No.: 17 of 25 • If any analyte does not meet the acceptance criteria, (85-115% recovery, unless other criteria are established) the test must be repeated. Only those analytes that did not meet criteria in the first test need to be evaluated. Repeated failure for any analyte indicates the need for the laboratory to evaluate the analytical procedure and take corrective action. 12.4 Training Requirements

12.4.1 Each analyst performing the method must complete a demonstration of capability (DOC) by successfully preparing and/or analyzing four consecutive LCSs, or a blind performance evaluation (PE) sample, or other acceptable QC samples. Analysts who continue to perform the method must successfully complete a demonstration of capability annually.

13.0 Pollution Control

13.1.1 For information about pollution prevention that may be applicable to laboratory operations, consult “Less is Better: Laboratory Chemical Management for Waste Reduction” av ailable from the American Chemical Society’s Department of Government Relations and Science Policy, 1155 16th Street N.W., Washington, D.C., 20036, or online at http://www.ups.edu/x7432.xml.

14.0 Waste Management All waste must be disposed of in accordance with Federal, State, and local regulations.

15.0 References / Cross-References

15.1 EPA Method 200.8, “Determination of Trace Elements in Waters and Wastes by Inductively Coupled Plasma - Mass Spectrometry”, Revision 5.4, EMMC Version.

15.2 EPA Method 1638, “Determination of Trace Elements in Ambient Waters by Inductively Coupled Plasma – Mass Spectrometry, January 1996

16.0 Attachments Attachment 1: Recommended Elemental Equations Attachment 2: Internal Standards and Corresponding Metals Attachment 3: Sample Preservation and Holding Times Attachment 4: Suggested Mass Choices Attachment 5: Tuning Solution Attachment 6: Suggested Tuning and Response Factor Criteria Attachment 7: Summary of Quality Control Requirements Attachment 8: Calibration, Calibrati on Verification, and Spike ConcentrationsEPA Office of Water May 20, 2010 Engineering & Analysis Division

Page No.: 18 of 25 Attachment 1 Recommended Elemental Equations

Element Isobaric Correction Mathematical Equation Pb None (1.0000)(208M) + (1.0000)(207M) + (1.0000)(206M) 6Li Li (natural) (1.0000)(6M) - (0.0813)(7M) In Sn (1.0000)(115M) - (0.0149)(118M)

The 6 Li correction equation is only needed if 6Li is used as an internal standard for low mass elements.

Attachment 2: Internal Standards and Corresponding Metals

Internal Std. Associated elements 1,2
Sc Na, Mg, Al, K, Ca, V, Cr, Mn
Ge Fe, Ni, Cu, Zn, As, Se In Ag, Cd
Ho Tl, Pb

Footnote: (1) Na, Mg, K, Ca and Fe are included in the synthetic FGD wastewater but their analytical determination is optional – the interferences caused by these elements is more important than the determination of their exact concentration. (2) Other internal standards may be used. For example, 6 Li, Ga, Rh, Bi, Ho and Tb may be considered for use as internal standards.EPA Office of Water May 20, 2010 Engineering & Analysis Division

Page No.: 19 of 25 Attachment 3: Sample Preservation and Holding Times

Measurement

Parameter Container (1) Preservative (2) Maximum Holding Time (3)

Waters: Metals (4) P,G HNO 3 to pH < 2 6 months

Soils/Sediments/Wastes: The preservation required for soil/sediment/waste samples is maintenance at 4°C ( ± 2°C) until digestion.

Footnotes : (1) Polyethylene (P) or glass (G). (2) Sample preservation is performed by the sampler immediately upon sample collection or shipped to the laboratory unpreserved for preservation at the laboratory. (3) Samples must be analyzed as soon as possible after collection. The times listed are the maximum times that sample may be held before analysis and still considered valid. Holding times are calculated from the date when the sample was collected. (4) Samples are filtered immediately on-site by the sampler before adding preservative for dissolved elements.EPA Office of Water May 20, 2010 Engineering & Analysis Division

Page No.: 20 of 25 Attachment 4: Suggested Mass Choices

Masses listed indicate the masses which have the most impact on data quality and the elemental equations used to collect the data.

Mass Element of Interest Analysis mode
27 Aluminum No gas
75 Arsenic He
111 Cadmium He
52 Chromium He
63 Copper He 208, 207, 206 Lead No gas or He
24 Magnesium No gas
55 Manganese He
60 Nickel He
39 Potassium No gas or He
78 Selenium He (H 2 )
107 Silver He
23 Sodium No gas or He
205 Thallium No gas or He
51 Vanadium He
66 Zinc He

NOTE : It is strongly recommended that elements other than those of interest be monitored to indicate other potential molecular interferences which could affect the data quality.EPA Office of Water May 20, 2010 Engineering & Analysis Division

Page No.: 21 of 25 Attachment 5: Tuning Solution A tuning solution containing elements representing all of the mass regions of interest must be analyzed. Below are two groups of suggested solutions which cover a typical mass calibration range.

Method 200.8

Element Concentration ( μ g/L) Mg 10

Rh 10

Ba 10

Be 10

U 10

Ce 10

Y 10

Pb 10

Li 10

Co 10

In 10

Tl 10EPA Office of Water May 20, 2010 Engineering & Analysis Division

Page No.: 22 of 25 Attachment 6: Suggested Tuning and Response Factor Criteria

No Gas Mode

Li7 >2000cps Tl205 >3000cps CeO/Ce 156/140 1% Ce++/Ce+ 70/140 <3%

He Mode: ArAr 78 2-3 counts/sec ArCl 75 2-3 counts/secEPA Office of Water May 20, 2010 Engineering & Analysis Division

Page No.: 23 of 25 Attachment 7: Summary of Quality Control Requirements

QC Parameter Frequency* Acceptance Criteria Corrective Action
ICV/QCS Beginning of every analytical run. 90 - 110% recovery. 200.8 IS, 60-125% rec. Terminate analysis; correct the problem; recalibrate. ICB/CCB Immediately after each ICV. The result is < RL 200.8 IS, 60-125% rec. Terminate analysis; correct the problem; recalibrate. Synthetic FGD interference check Prior to initiating analysis and at least quarterly. Result for target elements is < RL, unless actual presence of target element can be demonstrated, in which case result is < 5X RL. Correct the problem prior to sample analysis.

Individual element interference checks Prior to initiating analysis and at least quarterly. Result for target elements is < RL, unless actual presence of target element can be demonstrated, in which case result is < 5X RL. Correct the problem prior to sample analysis.

CCV Beginning and end of run and every 10 samples OR every 2 hours, whichever is more frequent. Beginning and end of each lot. 90 - 110% recovery.

IS, 60-125% rec. If unacceptable, terminate analysis; correct the problem; recalibrate the instrument, reverify calibration and rerun all samples since the last acceptable CCV. CCB Immediately following each CCV. The result must be < RL 200.8 IS, 60-125% rec. If unacceptable, terminate analysis; correct the problem recalibrate the instrument, reverify calibration and rerun all samples since the last acceptable CCB.EPA Office of Water May 20, 2010 Engineering & Analysis Division

Page No.: 24 of 25 Attachment 7: Summary of Quality Control Requirements (continued)

QC Parameter Frequency* Acceptance Criteria Corrective Action

Method Blank/Laboratory Reagent Blank One per lot of 20 field samples or fewer. The result must be less than the RL.

Sample results greater than 10x the blank concentration or samples for which the contaminant is < RL, do not require redigestion or reanalysis. Re-run once. If > than the RL, Redigest and reanalyze samples.

Note exceptions under criteria section.

See Section 9.4 for additional requirements.

Matrix Spike/Laboratory Fortified Matrix One every ten samples or fewer. Must be within laboratory control limits. See section 9.6 for additional requirements.EPA Office of Water May 20, 2010 Engineering & Analysis Division

Page No.: 25 of 25 Attachment 8: Calibration, Calibration Verification, and Spike Concentrations

Element Initial Calibration ( μ g/L) ICV ( μ g/L) CCV ( μ g/L) LCS ( μ g/L) MS/MSD ( μ g/L)

Aluminum 100, 1,000, 10,000 4000 5000 4000 4000

Arsenic 1, 10, 100 40 50 40 40

Cadmium 1, 10, 100 40 50 40 40

Chromium 1, 10, 100 40 50 40 40

Copper 1, 10, 100 40 50 40 40

Lead 1, 10, 100 40 50 40 40

Manganese 1, 10, 100 40 50 40 40

Nickel 1, 10, 100 40 50 40 40

Selenium 1, 10, 100 40 50 40 40

Silver 1, 10, 100 40 50 40 40

Thallium 1, 10, 100 40 50 40 40

Vanadium 1, 10, 100 40 50 40 40

Zinc 1, 10, 100 40 50 40 40

Additional elements may be included in the calibration solution at the above levels. Levels may be adjusted to meet specific requirements.

####