Timberline Ammonia-001 

Determination of Inorganic Ammonia by 

Continuous Flow Gas Diffusion and 

Conductivity Cell Analysis

Prepared By: Dr. Edward F. Askew

Date: June 24, 2011
Page 2 of 16

Table of Contents

1. SCOPE and APPLICATION........................................................................................ 3

2. SUMMARY.................................................................................................................. 3

3. DEFINITIONS.............................................................................................................. 3

4. INTERFERENCES....................................................................................................... 5

5. SAFETY ....................................................................................................................... 5

6. EQUIPMENT AND SUPPLIES................................................................................... 5

7. REAGENTS AND STANDARDS............................................................................... 6

Table 1: Ammonia Stock Standards ................................................................................... 7

Table 2: Membrane Dynamic Range .................................................................................. 8

8. SAMPLE COLLECTION, PRESERVATION, SHIPMENT, DIGESTION and 

STORAGE.............................................................................................................................. 8

9. QUALITY CONTROL................................................................................................. 8

10. PROCEDURE............................................................................................................. 10

11. CALCULATIONS / DATA REDUCTION................................................................ 12

12. METHOD PERFORMANCE..................................................................................... 14

13. POLLUTION CONTROL .......................................................................................... 15

14. WASTE MANAGEMENT......................................................................................... 15

15. REFERENCES / BIBLIOGRAPHY........................................................................... 15
Page 3 of 16

1. SCOPE and APPLICATION

1.1. Ammonia gas permeation through a hydrophobic membrane is used to determine 

ammonia concentration in aqueous solutions. 

1.2. For the determination of total ammonia from solutions that contain organic nitrogen 

(Kjeldahl nitrogen) and inorganic ammonia in aqueous and solid samples, a Kjeldahl

digestion is required prior to analysis.

1.3. Detection limits and linear ranges for organic and inorganic ammonia will vary with the 

matrices. Tables B and C in Section 16 provide pooled results for method detection limit 

(MDL) and minimum level (ML) determined from the inter-laboratory method 

validation study for 4 inch or 10 inch membranes. However, actual method detection 

limits and linear working ranges will be dependent on the sample matrix, 

instrumentation, and selected operating conditions.

1.4. Users of the method data should state the data-quality objectives prior to analysis. Users 

of the method must document and have on file the required initial demonstration of 

capability data described in Section 9.2 prior to using the method for analysis.

2. SUMMARY

2.1. An aqueous sample is combined with 1-15% sodium hydroxide to attain a pH above 11

producing ammonia in a non-ionized form in solution.

NH4

+

(aq) + OH-

(aq) → NH3(g)+ H2O(aq)

2.2. This solution is conveyed to a membrane assembly and the gaseous ammonia in the 

aqueous sample migrates through the hydrophobic membrane into the borate buffer 

absorption solution, which is transported to a conductivity cell. 

2.3. The measured changes in conductivity are used to quantitate ammonia in the sample 

using an external calibration.

3. DEFINITIONS

3.1. Ammonia Stock Standard Solution: A concentrated solution containing method analyte 

prepared in the laboratory using assayed reference materials or purchased from a 

reputable commercial source.

3.2. Calibration Blank: A volume of reagent water acidified with the same acid matrix as in 

the calibration standards. The calibration blank is a zero standard and is used to calibrate 

the ammonia analyzer.

3.3. Calibration Standard: A solution prepared from the dilution of stock standard solutions. 

These solutions are used to calibrate the instrument response with respect to analyte 

concentration.

3.4. Continuing Calibration Verification (CCV): Ammonia standard that has a concentration 

between the lower calibration standard and upper calibration standard. A CCV will be 

run at least once per batch.
Page 4 of 16

3.5. Control Charts: Graphical charts that contain the expected value (the central line) and the

acceptable range of occurrence. The acceptable range is determined from the control 

limits and warning limits. Refer to Part 1000 of Standard Methods for the Examination 

of Water and Wastewater for further explanation and guidance.

3.6. Dynamic Range (DR): The concentration range over which the instrument response to 

an analyte is second order quadratic. This range is defined by the concentration range 

between the lowest concentration standard and the highest concentration standard.

3.7. Instrument Detection Limit (IDL): The concentration equivalent to the analyte signal 

which is equal to replicate measurements of the calibration blank.

3.8. Initial Demonstration of Capability (IDC) also called a Initial Precision and Recovery 

(IPR): IDC/IPR are run by analysts with no experience with this method before they run 

any samples to verify their capability with the method or when significant maintenance 

or modifications are performed on the instrument. A laboratory fortified blank (LFB) is 

analyzed four times, the mean recovery and standard deviation are calculated and 

compared to the limits listed in this method for IDC/IPR.

3.9. Instrument Performance Check (IPC) Solution: A solution of method analyte, used to 

evaluate the performance of the instrument system with respect to a defined set of 

method criteria.

3.10. Laboratory Fortified Blank (LFB): An aliquot of ammonia free reagent water to which 

known quantities of ammonia is added in the laboratory. The LFB is 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.

3.11. Laboratory Fortified Sample Matrix/Duplicate (LFM/LFMD) also called a Matrix 

Spike/Duplicate (MS/MSD): An aliquot of an environmental sample to which known 

quantities of ammonia is added in the laboratory. The LFM/LFMD are analyzed exactly 

like a sample, and there 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 

LFM/LFMD corrected for background concentrations.

3.12. Laboratory Reagent Blank (LRB): An aliquot of reagent water or other blank matrices 

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

solvents, reagents, and internal standards that are used with other samples. The LRB is 

used to determine if method analytes or other interferences are present in the laboratory 

environment, reagents or apparatus.

3.13. Method Detection Limit (MDL): The minimum concentration of an analyte that can be 

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

greater than zero. Full requirements are listed in 40 CFR Part 136 Appendix B.

3.14. Minimum Level (ML): Minimum level is determined by multiplying the MDL by 3.18 

and rounding the product to the number nearest to 1 or 2 or 5 x 10n

, where n is a positive 

or negative integer. The minimum level is used to determine the lowest standard 

concentration that can be used for the instrument.
Page 5 of 16

3.15. Ongoing Demonstration of Capability (ODC) also called Ongoing Precision and 

Recovery (OPR): ODC/OPR are performed at least once per sample batch to 

demonstrate proficiency with the method. Reagent water is spiked with known quantities 

of ammonia. Its purpose is to assure that the results produced by the laboratory remain 

within the limits specified in this method for precision and recovery.

3.16. Sample 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 batch. A batch cannot span between 

laboratory work days (24 hrs). New batches must be started each laboratory work day.

3.17. Solid Sample: For the purpose of this method, a sample taken from material classified as 

soil, sediment or sludge that is digested by the Total Kjeldahl Nitrogen method.

3.18. Total Kjeldahl Nitrogen: Digestion method of water or solid samples by methods 

currently approved in 40 CFR 136, Table IB.

3.19. Water Sample: For the purpose of this method, a sample taken from one of the following 

sources: surface, ground, storm runoff, industrial or domestic wastewater.

4. INTERFERENCES

4.1. Volatile amines can diffuse through the hydrophobic membrane to produce a 

conductivity response. Generally, interference from low molecular weight amines is not 

a practical problem because their natural occurrence is so limited.

4.2. Chloramines can decompose to produce ammonia.

4.3. Deionized water used in reagents and standards must be high quality and ammonia-free 

to avoid interference. 

5. SAFETY

5.1. This method does not address all safety issues associated with its use. The laboratory is 

responsible for maintaining a safe work environment and a current awareness file of 

OSHA regulations regarding the safe handling of any chemicals specified in this method. 

A reference file of material safety data sheets (MSDSs) should be available to all 

personnel involved in these analyses.

6. EQUIPMENT AND SUPPLIES

6.1. Sample Containers: As per current 40 CFR Part 136 Table II, polyethylene, 

fluoropolymer or glass..

6.2. Class A Volumetric Flasks: various sizes used for preparation of standards.

6.3. Test Tubes: 15 x 85 mm; used in autosampler.

6.4. Analytical Balance: analytical, capable of accurately weighing to 0.0001 ± 0.00005 g.

6.5. pH METER: double junction electrode; used when adjusting the pH of the boric acid 

solution.
Page 6 of 16

6.6. Ammonia Analyzer with gas permeation cell and conductivity detector: Timberline 

Instruments TL-2800 Ammonia Analyzer or an equivalent instrument that uses the same 

chemistry/determinative techniques and can meet the QC performance criteria set in the 

method.

7. REAGENTS AND STANDARDS

7.1. Reagent Water – Deionized water that does not contain measurable quantities of 

ammonia above the detection level of the dynamic range or any interfering volatile 

conductive compounds. This water will be used for all standards, calibration zero, LRB, 

LFB, and sample dilutions preparation. 

(Note: Prolonged storage of reagent water will expose it to ammonia absorption from 

the laboratory environment. Prepare fresh as needed.)

7.2. Caustic Solution: Sodium Hydroxide (NaOH) or Potassium Hydroxide- 50% (w/v) 

solution. Prepare by weighing a known amount of ACS or better grade sodium 

hydroxide or potassium hydroxide to the nearest gram and add slowly to a known 

volume of reagent water in mL with the ratio of 1 gram sodium hydroxide or potassium 

hydroxide to 1 mL of reagent water. Mix thoroughly in a beaker with a magnetic stirrer. 

(Caution: Reaction produces excessive heat and is caustic to unprotected skin. 

Prolonged storage of reagent water will expose it to ammonia absorption from the 

laboratory environment. Prepare fresh as needed.)

7.3. Caustic Working Solutions – 1-15% (w/v). Select caustic solution as needed per sample 

characteristics. Selection is based on the caustic solutions ability to raise the pH of the 

sample to a point that free ammonia is formed to diffuse through the membrane.

Typically, with most ammonia concentrations, the 5% caustic solution is utilized. Other 

caustic solution concentrations may be needed based on higher ammonia concentrations, 

lower ammonia concentration or water matrix. Final caustic solution concentration will 

be based on ammonia concentration in the sample, the water matrix and QC performance 

requirements.

7.3.1. 1 %: Dilute 20 ml of 50% (w/w) sodium hydroxide or potassium hydroxide

solution to 1 L with reagent water. Mix well by inversion. Prepare fresh weekly

7.3.2. 5 %: Dilute 100 ml of 50% (w/w) sodium hydroxide or potassium hydroxide 

solution to 1 L with reagent water. Mix well by inversion. Prepare fresh weekly.

7.3.3. 10%: Dilute 200 ml of 50% (w/w) sodium hydroxide or potassium hydroxide 

solution to 1 L with reagent water. Mix well by inversion. Prepare fresh weekly.

7.3.4. 15%: Dilute 300 ml of 50% (w/w) sodium hydroxide or potassium hydroxide 

solution to 1 L with reagent water. Mix well by inversion. Prepare fresh weekly.

7.4. Boric Acid Solution 10,000 ppm boric acid (H3BO3). Add 10 ± 0.001 g of ACS grade or 

better boric acid in a 1 L volumetric flask and dilute to volume with reagent water. Mix

until the boric acid has completely dissolved in the solution.

(Note: Prolonged storage of Boric Acid will expose it to ammonia absorption from the

laboratory environment. Prepare fresh as needed.)
Page 7 of 16

7.5. Ammonium Hydroxide (NH4OH) - 1.0 N. Transfer 135 mL of 28% ACS grade or better 

ammonium hydroxide to ~ 100 mL of reagent water in a 1 L volumetric flask. Dilute to 

the mark with reagent water and mix well. Make fresh monthly.

7.5.1. Ammonium Hydroxide Working Solutions - 0.01 N Ammonium hydroxide.

Transfer 1 mL of 1 N ammonium hydroxide to 100 mL volumetric flask. Dilute to 

volume with reagent water. Mix well by inversion. Prepare fresh weekly.

7.6. Buffer Solutions – pH adjusted Boric acid, Select boric acid solution as needed per 

sample characteristics. Typically, with most ammonia concentrations, the 250 ppm 

Buffer Solution is utilized. Other Buffer Solution concentrations may be needed based 

on higher ammonia concentrations (100 ppm ammonia or greater) or lower ammonia 

concentration (0.1 ppm or lower).Final Buffer Solution concentration will be based on 

ammonia concentration in the sample and QC performance requirements.

7.6.1. 100 ppm. Transfer 10 mL of the 10,000 ppm boric acid solution to a 2 L beaker. 

Add ~ 975 mL of reagent water. While stirring adjust the pH to 6.5-7 using 0.01 

or 0.02 N ammonium hydroxide solution. Prepare fresh weekly

7.6.2. 250 ppm. Transfer 25 mL of the 10,000 ppm boric acid solution to a 2 L beaker. 

Add ~ 930 mL of reagent water. While stirring adjust the pH to 6.5-7 using 0.01 

or 0.02 N ammonium hydroxide solution. Prepare fresh weekly.

7.6.3. 400 ppm. Transfer 40 mL of the 10,000 ppm boric acid solution to a 2 L beaker. 

Add ~ 875 mL of reagent water. While stirring adjust the pH to 6.5-7 using 0.01 

or 0.02 N ammonium hydroxide solution. Prepare fresh weekly.

7.7. Ammonia Standard Solutions

7.7.1. Calibration Blank: Reagent water. Replace daily or per analytical batch.

7.7.2. Ammonia Stock Solution: Accurately weigh out, to the nearest 0.001 ± 0.0005 g, 

dried (at 100o C) ACS grade ammonium sulfate (NH4)2SO4 or ammonium 

chloride (NH4Cl) to make the desired ammonia concentration in Table 1, below. 

Transfer the reagent to a 1L volumetric flask and dilute to volume with reagent 

water. Mix well by inversion. Prepare fresh monthly.

Table 1: Ammonia Stock Standards

Ammonium Salt Ammonium Chloride Ammonium Sulfate

Molecular Weight 53.49 132.14

Ammonia-N Concentration Ammonia Salt Weight (g)

2000 mg/L 7.641 18.877

500 mg/L 1.910 4.719

100 mg/L 0.382 0.944

10 mg/L 0.038 0.094

7.7.3. Calibration Standards –A minimum of 5 calibration concentrations along with a 

calibration blank will be required to prepare the initial calibration curve and 
Page 8 of 16

ongoing calibration curve. The calibration curve fit can be either linear or 

quadratic, but must have a R value of 0.995 or higher. Prepare the calibration 

standards over the dynamic range of interest as defined in Table 2 from dilutions 

of the ammonia stock solution. The calibration standards must be prepared using 

regent grade water and prepared fresh weekly.

Table 2: Membrane Dynamic Range

Membrane Type Membrane Length (Inches)

Concentration Calibration 

Dynamic Range

(Ammonia-N mg/L)

High Sensitivity 10 2-0.020

Standard 4 500-0.0500

8. SAMPLE COLLECTION, PRESERVATION, SHIPMENT, DIGESTION and

STORAGE

8.1. Sample Collection

8.1.1. Collect and store ammonia or Kjeldahl samples in glass or high density 

polyethylene bottles. Most reliable results are obtained on fresh samples.. For 

preservation for up to 28 d, preserve samples by acidifying to pH <2 with sulfuric 

acid upon collection and store at 6°C to just above 0°C, without freezing

8.2. Total Kjeldahl Nitrogen Digestion

8.2.1. Digest Kjeldahl sample as per approved method in 40 CFR Part 136 Table IB

(e.g. 4500-Norg -1997). Digested sample is stored in a covered borosilicate 

container at room temperature until analyzed. Analyze within 4 hours of digestion 

completion.

9. QUALITY CONTROL

9.1. Ongoing data quality checks are compared with established performance criteria to

determine if the results of analyses meet the performance characteristics of the method. 

Control charts of each QC check will be kept and appropriate control limits calculated. 

Any QC result that fails to meet control criteria must be documented and corrective 

action, including a root cause analysis, must be performed.

9.2. Initial Demonstration of Capability: A laboratory fortified blank whose concentration is 

between the 10% and 50% of the dynamic range is analyzed four times. The mean 

recovery and standard deviation are calculated and evaluated for acceptance.

9.2.1. Acceptance Criteria: IDC control limit for the laboratory is based on the limits 

determined in this method and shall not exceed 82%-110 % with a percent 

Relative Standard Deviation less than 8%. 

9.2.2. Corrective Action: If the IDC recovery falls outside of these limits, the analyst 

or instrument is judged to be out of control. A root cause analysis must be 

performed, corrective action taken, all findings recorded and the IDC repeated 

until passed.
Page 9 of 16

9.3. Continuing Calibration Verification: At least one CCV standard will be prepared so as to 

have a concentration in the dynamic range of the instrument. The CCV will be run at 

least once per each batch. The CCV percent recovery is calculated and evaluated for 

acceptance.

9.3.1. Acceptance Criteria: CCV control limit for the laboratory is based on the limits 

determined in this method and shall not exceed 90%-110 %. 

9.3.2. Corrective Action: If the CCV recovery falls outside of these limits, the batch is 

judged to be out of control. A root cause analysis must be performed, corrective 

action taken, all findings recorded and the sample batch repeated.

9.4. Laboratory Reagent Blank: A LRB is analyzed as a sample at least once per batch. The 

LRB concentration result will be evaluate for acceptance.

9.4.1. Acceptance Criteria: The LRB concentration result will be below the lowest 

calibration standard in the dynamic range.

9.4.2. Corrective Action: If the LRB falls outside of the acceptance limit, the batch is 

judged to be out of control. A root cause analysis must be performed, corrective 

action taken, all findings recorded and the sample batch repeated.

9.5. Laboratory Fortified Blank: A LFB with a concentration of ammonia between 10% and 

50% of the dynamic range is analyzed at least once per batch. The LFB concentration 

result will be evaluate for acceptance.

9.5.1. Acceptance Criteria: LFB percent recovery is based on the limits determined in 

this method and shall not exceed 87%-104 %. 

9.5.2. Corrective Action: If the LFB recovery falls outside of these limits, the batch is 

judged to be out of control. A root cause analysis must be performed, corrective 

action taken, all findings recorded and the sample batch repeated.

9.6. Laboratory Fortified Sample Matrix Spikes (LFM/LFMD): A duplicate set of ammonia 

or Kjeldahl samples are spiked with a known amount of ammonia with a concentration 

that is between 10% and 50% of the dynamic range

9.6.1. Acceptance Criteria: The LFM/LFMD percent recovery is based on the limits 

determined in this method and shall not exceed 84%-115 %. The relative 

percent difference (RPD) shall not exceed 20%.

9.6.2. Corrective Action: If the LFM and LFMD percent recovery or the RPD fall

outside of these limits, the batch is judged to be out of control. A root cause 

analysis must be performed, corrective action taken, all findings recorded and 

the sample batch repeated.

9.7. Ongoing Demonstration of Capability (ODC): A LFB with a concentration of ammonia 

between 10% and 50% of the dynamic range is analyzed at least once per batch. The 

LFB percent recovery will be charted by control charts and be evaluated for acceptance.

9.7.1. Acceptance Criteria: LFB percent recovery must stay within the control limits 

calculated for the control chats. 

9.7.2. Corrective Action: If the LFB percent recovery falls outside of these control 
Page 10 of 16

limits, the batch is judged to be out of control. A root cause analysis must be 

performed, corrective action taken, all findings recorded and the sample batch 

repeated.

10.PROCEDURE

10.1. Sample Analysis Sequence: Typical sample analysis sequence .

10.1.1. Instrument Start Up

10.1.2. Calibration zero

10.1.3. Calibration standards, 1-5

10.1.4. LRB

10.1.5. LFB

10.1.6. Sample used for LFM/LFMD

10.1.7. LFM

10.1.8. LFMD

10.1.9. Samples (First half of batch)

10.1.10. CCV

10.1.11. Samples (Second half of batch)

10.1.12. Repeat CCV (Optional)

10.2. Instrument Preparation

10.2.1. Start the instrument as per the Timberline TL2800 instrument manual (or an 

equivalent instrument that uses the same chemistry/determinative techniques 

and can meet the QC performance criteria set in the method.).

10.2.2. Prepare quality control samples.

10.3. Sample Preparation

10.3.1. Remove refrigerated samples from the refrigerator and warm to room 

temperature.

10.3.2. Kjeldahl digested samples are diluted 10:1 with the reagent water to achieve a 

nominal 10% (wt) sulfuric acid.

10.3.3. Spike the LFB and LFM/LFMD per QC spiking requirement.

10.3.4. Prepare CCV standard.

10.3.5. Prepare LRB water.

10.3.6. Prepare a calibration zero that is ammonia free water.

10.3.7. Prepare five (5) calibration standards that bracket the dynamic range of the 

analysis. The lowest concentration standard must be at or above the ML.

10.3.8. Transfer aliquots of all samples to autosampler tubes.
Page 11 of 16

10.4. Initial Calibration: 

10.4.1. Initial calibration is performed at the beginning of each batch.

10.4.2. Calibrate instrument with calibration zero and five calibration standards of 

ammonia. 

10.4.3. Apply linear or polynomial curve-fitting statistics, as appropriate, to analyze the 

concentration–instrument response relationship. 

10.4.3.1. Acceptance Criteria: The linear or nonlinear correlation coefficient for 

standard concentration-to-instrument response shall be greater than or 

equal to 0.995. 

10.4.3.2. Corrective Action: If the correlation coefficient falls outside of the limit, 

the initial calibration is judged to be out of control. A root cause analysis 

must be performed, corrective action taken, all findings recorded and the 

initial calibration repeated.

10.4.4. Back calculate the standard concentration of each calibration point using the 

calibration equation determined by the curve fitting statistics. 

10.4.4.1. Acceptance Criteria: The back-calculated and true concentrations should 

agree within ± 10% and cannot exceed ± 15%.

10.4.4.2. Corrective Action: If the standard back calculations fall outside of the 

limits, the initial calibration is judged to be out of control. A root cause 

analysis must be performed, corrective action taken, all findings recorded 

and the initial calibration repeated.

10.5. Continuing Calibration Verification:

10.5.1. A CCV is analyzed at the midpoint of the batch sample set. The CCV is prepared 

from a different source (chemical lot) than that used for the calibration standards.

10.5.1.1. Acceptance Criteria: CCV control limit for the laboratory is based on the 

limits determined in this method and shall not exceed 90%-110 %. 

10.5.1.2. Corrective Action: If the CCV recovery falls outside of these limits, the 

batch is judged to be out of control. A root cause analysis must be 

performed, corrective action taken, all findings recorded and the sample 

batch repeated.

10.6. Sample Analysis

10.6.1. Operate the instrument as per manual instructions.

10.6.2. Report the values of all samples and QC samples analyzed.

10.6.3. Determine the appropriate timing parameters and integration times for the peaks.

10.6.4. Load the filled autosampler tubes into the autosampler and start the injection

sequence.

10.6.5. Calibrate the system by generating a calibration curve with 5 standards and an 

instrument blank.
Page 12 of 16

Note: (For Kjeldahl samples) The samples need to be run with a 10-15% (w/v) NaOH 

solution to neutralize the acid (22.5% molar excess).

10.6.6. Analyze the samples and QC checks. The sample concentration should not exceed 

the range of the initial calibration curve. If the sample does fall outside the range 

of the calibration, a new calibration curve should be run to include the range of 

the sample or the sample should be diluted with reagent water to a concentration 

within the dynamic range.

11.CALCULATIONS / DATA REDUCTION

11.1. Calculate the ammonia concentrations using the initial calibration curve generated. The 

batch should be reviewed for any incorrect peak identification or poor integration.

11.2. Samples and QC sample final concentrations are calculated as follow :

11.2.1. (s x DilutedSampleConcentration) = Sample Concentration

s=Dilution Correction

11.3. Laboratory Reagent Blank (LRB); The LRB will be run at a minimum of once per 

sample batch. Results are reported as sample concentration and should be at or below the 

ML. Laboratory Fortified Blank (LFB): The LFB percent recovery is calculated as 

follows:

11.3.1. Percent Recovery for LFB

 

Experimental Value *100= Percent Recovery LFB Expected Value

Experimental Value = LFB Concentration determined experimentally

Expected Value = Known LFB concentration

     

11.4. Initial Demonstration of Capability (IDC) is determined by calculating for four LFBs, 

the mean percent recovery and standard deviation. 

11.4.1. ( ) i i (Mean)= n

x x ∑

11.4.2.

1

n 2 2

i

i=1 (StandardDeviation)=

(X -X)

n-1

s

  ∑ 

 

   

11.4.3. % Relative Standard Deviation = S/x ×100 ( )

11.5. Laboratory Fortified Sample Matrix -Laboratory Fortified Sample Matrix Duplicate

(LFM-LFMD): The LFM/LFMD percent recoveries and RPD are calculated as follows:
Page 13 of 16

11.5.1. Percent Recovery for LFM

Spiked Value-(s x Unspiked Value) *100= Percent Recovery LFM Concentration of Spike

Spiked Value = LFM concentration determined experimentally

Unspiked Value = Concentration of sample before spiking

s=Diluti

     

on Correction

11.5.2. Relative Percent Difference (RPD)

(LFM-LFMD) *100 = RPD

LFM+LFMD

2

LFM = Concentration determined for LFM

LFMD = Concentration determined for LFM duplicate

   

 

         

11.6. Continuing Calibration Verification (CCV): Check standards will be prepared so as to 

have a concentration between the lower and upper calibration of the dynamic range. 

11.6.1. CCV Value - InitialStandard Value 100 Percent Difference

InitialStandard Value ∗ =

11.7. Control Charts: Control charts will be kept for LFB and LFM percent recovery per 

sample batch, LFM and LFMD RPD per sample batch, and LRB concentration. Trends 

will be calculated to show whether the values determined go outside the control limits. If 

these trends exceed control limits of this method, then corrective action (Root Cause 

Analysis) must be performed.

11.8. Corrective Action (Root Cause Analysis): The laboratory analyst(s) and laboratory 

management will perform a root cause analysis for any QC failures. The analysis will 

have at a minimum the following areas described in detail:

11.8.1. Identify the problem: Identify the QC failure. Include instrument, reagent, 

sampling, personnel and any other problems.

11.8.2. Investigate to identify the root cause: Determine how each problem identified 

interacted with each other to create the QC problem. 

11.8.3. Come up with the solution: Develop an encompassing solution to address all 

problems that created the QC failure.

11.8.4. Implement the solution: Develop an implementation plan that includes all 

components of the developed solution and have laboratory management 

implement it.

11.8.5. Document the solution: Document all corrective action steps taken under 

laboratory management implementation of the corrective action.
Page 14 of 16

11.8.6. Communicate the solution: Develop training and management programs to 

communicate and evaluate all personnel included in the corrective action 

solution.

11.8.7. Evaluate the effectiveness of the solution: Document QC results in trend charts 

and laboratory staff performance to validate corrective action solution. 

12.METHOD PERFORMANCE

12.1. Method Detection Limit and Method Limit Study(MDL-ML): 

12.1.1. MDL and ML are determined for the initial start-up of the instrument prior to 

any sample analysis and when the instrument has had maintenance or repairs of 

the membrane, detector or any other internal analytical components. These 

requirements do not include consumable supplies or reagents. Analytical 

procedures for the MDL and ML are listed in the current promulgated 40 CFR 

136 Appendix B. 

12.1.2. Prepare seven samples at three to five times the estimated MDL concentration. 

The MDL samples are prepared in the Synthetic

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

12.1.4. Calculate the average concentration found in μg/L or mg/L, and the standard 

deviation of the concentration(s) for each analyte .

12.1.5. The MDL is calculated as Students t for the 99th percentile times the standard 

deviation of the MDL replicate results, following the procedure at 40 CFR 136, 

Appendix B.

12.1.6. The ML is calculated as per “Guidelines Establishing Test Procedures for the 

Analysis of Pollutants Under the Clean Water Act; National Primary Drinking 

Water Regulations; and National Secondary Drinking Water Regulations: 

Analysis and Sampling Procedures”.

12.1.7. (MDL x 3.18) = ML

12.2. Instrument Detection Limit Study: 

12.2.1. Prepare three laboratory reagent blanks.

12.2.2. Analyze the IDL blanks as per Section 10.

12.2.3. The IDL is calculated as per Standard Methods for the Examination of Water 

and Wastewater Part 1000.

12.2.4. LRB

LRB

Instrument Detection Limit = (3 × S )

S = Standard Deviation of Laboratory Reagent Blanks

12.3. Demonstration of Capabilities

12.3.1. All laboratory personnel are required to perform an initial demonstration of 

capability (IDC) on the instrument they will be using for analysis prior to 

testing samples. Ongoing demonstration of capability must be demonstrated by 
Page 15 of 16

control charts with LFBs being analyzed at least once per sample batch. Initial 

and ongoing demonstrations of capabilities are conducted as follows.

12.3.2. Initial Demonstration of Capability Analyst Proficiency - Four LFBs are 

analyzed using the same instrumental conditions and procedures used to 

analyze samples. Using these four LFBs demonstrates the analyst’s ability to 

optimize and calibrate the instrument and to prepare analytical solutions. 

Calculate the average percent recovery and standard deviation of the recovery.

12.3.2.1. Acceptance Criteria: IDC control limit for the laboratory is based on the 

limits determined in this method and shall not exceed 82%-110 % with a 

percent Relative Standard Deviation less than 8%. 

12.3.2.2. Corrective Action: If the IDC recovery falls outside of these limits, the 

analyst or instrument is judged to be out of control. A root cause analysis 

must be performed, corrective action taken, all findings recorded and the 

IDC repeated until passed.

12.3.3. Ongoing Demonstration of Capability Analyst Proficiency: A LFB is analyzed 

using the same instrumental conditions and procedures used to analyze samples 

at least once per batch. The LFB percent recovery will be charted by control 

charts and be evaluated for acceptance.

12.3.3.1. Acceptance Criteria: LFB percent recovery must stay within the control 

limits calculated for the control chats. 

12.3.3.2. Corrective Action: If the LFB percent recovery falls outside of these 

control limits, the batch is judged to be out of control. A root cause 

analysis must be performed, corrective action taken, all findings recorded 

and the sample batch repeated.

13.POLLUTION CONTROL

13.1. It is the laboratory’s responsibility to comply with all federal, state, and local regulations 

governing waste management, particularly the hazardous waste identification rules and 

land disposal restrictions, and to protect air, water, and land by minimizing and control 

all releases from fume hoods and bench operations. Compliance with all sewage 

discharge permits and regulations is also required.

14.WASTE MANAGEMENT

14.1. There are no standards or reagents used in this method at the concentrations required that 

pose a threat to the environment. Refer to Local, State or Federal for correct disposal of 

all chemicals.

15.REFERENCES / BIBLIOGRAPHY

15.1. EPA, Guidelines Establishing Test Proceedures for the Analysis of Pollutants Under the 

Clean Water Act; National Primary Drinking Water Regulations; and National 

Secondary Drinking Water Regulations: Analysis and Sampling Proceedures. 2007. 

72(47): p. 11200-11249.
Page 16 of 16

15.2. EPA, 40 CFR Part 136-Guidelines Establishing Test proceedures for the Analysis of 

Pollutants, Appendix B, 1984.

15.3. EPA, Protocol for EPA Approval of New Methods for Organic and Inorganic Analytes 

in Wastewater and Drinking Water. 1999. 

15.4. Eaton, E., Clesceri, L., Rice, E., , ed. Standard Methods for the Examination of Water 

and Wastewater, 21st Edition. 2005, APHA, AWWA, WEF.

15.5. ASTM, Standard Test Methods for Ammonia Nitrogen In Water D1426-03 A. 2003, 

ASTM International.

15.6. ASTM, Standard Practices for determination of Precision and Bias of Applicable Test 

Methods of Committee D19 In Water D2777-06 2006, ASTM International

15.7. EPA. Draft 2009 Update of Aquatic Life Ambient Water Quality Criteria for Ammonia -

Freshwater 2010; Available from: 

http://www.epa.gov/waterscience/criteria/ammonia/factsheet2.html.

15.8. Bruce O. Mansell, L.D.V., Edward D. Schroeder Automated Separation and 

Conductimetric Determination of Inorganic Nitrogen. Journal of Enviornmental 

Engineering, 2000. 126(8): p. 778-780.

16. Skoog, D.A., et al, “Fundamentals of Analytical Chemistry”, Eighth Edition, 2004, 

Thomson, Brooks/Cole.