Severn Trent Laboratories Baltimore ANALYTICAL METHOD

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1 Severn Trent Laboratories Baltimore Number: STL-M-8021B Rev. No.: 1 Page 1 of 13 Aromatic Volatile Organics by Gas Chromatography Approved By: C. S. Schenning, Volatiles Section Chief Date Approved By: M. M. Uhlfelder, Quality Services Manager Date Approved By: A. R. Karimi, General Manager Date

2 This documentation has been prepared by Severn Trent Laboratories (STL) solely for STL s own use and the use of STL s customers in evaluating its qualification and capabilities in connection with a particular project. The user of this document agrees by its acceptance to return it to Severn Trent Laboratories upon request and not to reproduce, copy, lend, or otherwise disclose its contents, directly or indirectly, and not to use it for any other purpose other than that for which it was specifically provided. The user also agrees that where consultants or other outside parties are involved in the evaluation process, access to these documents shall not be given to said parties unless those parties also specifically agree to these conditions. THIS DOCUMENT CONTAINS VALUABLE CONFIDENTIAL AND PROPRIETARY INFORMATION. DISCLOSURE, USE OR REPRODUCTION OF THESE MATERIALS WITHOUT THE WRITTEN AUTHORIZATION OF SEVERN TRENT LABORATORIES IS STRICTLY PROHIBITED. THIS UNPUBLISHED WORK BY SEVERN TRENT LABORATORIES IS PROTECTED BY STATE AND FEDERAL LAW OF THE UNITED STATES. IF PUBLICATION OF THIS WORK SHOULD OCCUR THE FOLLOWING NOTICE SHALL APPLY: COPYRIGHT 1999 SEVERN TRENT LABORATORIES, INC. ALL RIGHTS RESERVED.

3 Severn Trent Laboratories Baltimore Number: STL-M-8021B Rev. No.: 1 Aromatic Volatile Organics by Gas Chromatography Page 2 of 13 Rev. No. Date Description Revisions 0 December 27, 1996 Initial distribution. 1 June 9, 1999 Removal of halogenated analytes, inclusion of 5035, edited to reflect change in ownership

4 Severn Trent Laboratories Baltimore Number: STL-M-8021B Rev. No.: 1 Page 3 of 13 Aromatic Volatile Organics by Gas Chromatography Controlled Distribution Name Manual No. Walt Miller 2 Athene Steinke 4 Natasha Sullivan 8 Craig Schenning 17

5 Aromatic Volatile Organics by Gas Chromatography Page 5 of 13 WHEN STAMPED IN RED, THIS IS A CONTROLLED COPY. IF STAMP IS NOT RED, VERIFY THAT YOU ARE USING THE CURRENT REVISION BEFORE PROCEEDING WITH WORK UNDER THIS PROCEDURE 1.0 SCOPE AND APPLICATION This method is used to determine the concentration of various volatile aromatic organic compounds. Table 1 lists the compounds that are routinely determined by this method, and the laboratory reporting limit for each analyte. Modifications to the analyte list and/or procedural changes to reach lower reporting limits are allowed if required by client, project or program. Any changes in the analytical procedures must be approved by the Section Chief, Operations Manager and the Quality Services Manager before samples can be analyzed. TABLE B ANALYTES ANALYTE CAS# (a) REPORTING LIMIT REPORTING LIMIT (µg/l) (µg/kg) Methyl tertiary butyl ether Diisopropyl ether Benzene Toluene Chlorobenzene Ethylbenzene m + p-xylenes / o-xylene ,3-Dichlorobenzene ,4-Dichlorobenzene ,2-Dichlorobenzene Naphthalene (a) Chemical Abstract Services Registry Number. Sample reporting limits are highly matrix-dependent. The reporting limits for various matrices are determined by multiplying the reporting limits in Table 1 by the factor in Table 2, with the appropriate concentration units (µg/l-water, µg/kg-soil). These are provided for guidance and may not always be achievable. TABLE 2. DETERMINATION OF REPORTING LIMITS FOR VARIOUS MATRICES Matrix Factor Water 1 Low-concentration soil 1 High-concentration soil and sludge SUMMARY OF METHOD This method provides gas chromatographic conditions for the detection of aromatic volatile organic compounds. Samples will be introduced into the GC via purge-and-trap. A temperature program is used in the gas chromatograph to separate the organic compounds. Detection is achieved by a photoionization detector (PID). 3.0 DEFINITIONS

6 Aromatic Volatile Organics by Gas Chromatography Page 6 of Organic-free reagent water refers to water in which no target analyte is observed at the reporting limit of the compounds of interest. Severn Trent Laboratories Baltimore uses a Culligan reverse osmosis (R/O) water purification system to generate organic-free deionized water. 3.2 Initial Calibration Verification/Laboratory Control Sample (ICV/LCS) is a second source calibration standard used to verify the initial calibration and evaluate method performance. It contains all of the analytes listed in Table 1 at a concentration of 50µg/L. The stock used to prepare the ICV must be from a source that is different from the stocks used to prepare the calibration standards. 3.3 Continuing Calibration Verification(CCV) is a mid-level calibration standard used to verify the initial calibration at the beginning and ending of each analytical sequence. 3.4 Matrix Spike/Matrix Spike Duplicate (MS/MSD) are two sample duplicates spiked with a representative subset of the analytes of interest and taken through the entire analytical procedure. 3.5 Method Blank is a reagent water or standard soil spiked with all surrogates of interest and taken through the entire analytical procedure. 3.6 Surrogate is a non-target compound spiked into all samples and QC samples and taken through the entire analytical procedure to determine purging efficiency, and any possible matrix bias. 4.0 SAMPLE COLLECTION, PRESERVATION, AND HANDLING 4.1 Under routine protocols, at least two aliquots are sent to the laboratory for each sample. Sample container, preservation and holding time requirements are given in Table 3. While samples are in the custody of the laboratory, samples are stored in the volatiles laboratory at 4EC ± 2EC prior to analysis. After analysis is completed, samples are stored by the Sample Management Office in laboratory walkins until disposal. 4.2 Prior to analysis the analyst must check the sample vials for the presence of air bubbles, and should notify the assigned Laboratory Project Manager (LPM) immediately, if present. The LPM will contact the client to determine if the analysis should proceed. The analyst must initiate a Nonconformance Record (NCR) as described in STL-SOP-072 and forward it to the LPM. 4.3 The sample vial (water samples) should indicate whether or not the sample has been preserved. The ph of the sample is determined after the sample aliquot is removed from the sample vial. Do not dip the ph strip into the sample vial before the sample aliquot is removed. Document the ph in the instrument log. The ph of the sample should be <2. Preserved samples with ph >2 constitute a nonconformance which must be documented via an NCR if the analyses is taking place after seven days from the collection date. Note: results from unpreserved samples may be biased low due to biological degradation of target analytes. Unpreserved samples need to be analyzed as soon as possible (no more than 7 days from the date of sample collection). Table 3. Recommended Sample Containers, Preservation Techniques, and Holding Times Parameter Container Preservative Holding Time Concentrated Waste Samples: Aromatic Volatiles 8-oz. wide mouth None 14 days glass with Teflon liner Liquid Samples:

7 Aromatic Volatile Organics by Gas Chromatography Page 7 of 13 Aromatic Volatiles (4) 40-mL vials with 4 drops conc. HCl, Cool, 4EC 14 days (7 days Teflon lined septum for unpreserved caps samples) Soil/Sediments and Sludges: Aromatic Volatiles 4 oz (120-mL) wide Cool to 4EC 14 days (STL-M-5030A) mouth glass with Teflon liner

8 Aromatic Volatile Organics by Gas Chromatography Page 8 of 13 Table 3. Recommended Sample Containers, Preservation Techniques, and Holding Times Soil/Sediments and Sludges: Aromatic Volatiles Encore Sampler - a 0.2 grams of sodium bisulfate 48 hrs from time (STL-M-5035, STL-M- hermetically sealed for each 1.0 gram of sample, of collection to 5030B) sample vial Cool to 4EC sealed vial then 14 days 5.0 INTERFERENCES 5.1 Contamination by carryover can occur whenever high-concentration and low-concentration samples are sequentially analyzed. To reduce carryover, the purging device must be rinsed out between samples with water or solvent. Whenever an unusually concentrated sample is encountered, it should be followed by an analysis of a instrument blank to check for cross contamination. For volatile samples containing large amounts of water-soluble materials, suspended solids, high boiling compounds or high organohalide concentrations, it may be necessary to wash out the purging device with a detergent solution, rinse it with distilled water, and then dry it in a 105EC oven between analyses. 5.2 UST samples with high levels of hydrocarbon contamination may have interfering coelution with the target analytes which will result in false positive results or biased high results. If this situation occurs, GC/MS analysis is recommended. Notify Section Chief and LPM prior to reporting analysis results. 6.0 APPARATUS AND MATERIALS 6.1 Gas chromatograph: analytical system complete with gas chromatograph suitable for purge-and-trap sample introduction and all required accessories, including detector, analytical columns, data system, and gases Columns: Wide bore capillary column (105 m x 0.53 mm ID). Example of phases include but are not limited to RTX-502.2, RTX-1, DB-VRX (75m x 0.45mm ID), and DB-624 (75m x 0.53 ID) Detector: Photoionization (PID). 6.2 Glass scintillation vials: both 20 ml and 40 ml, with screw-caps and Teflon liners or glass culture tubes with a screw-cap and Teflon liner. 6.3 Spatula: Stainless steel. 6.4 Disposable pipettes: Pasteur. 6.5 Purge-and-trap device: The purge-and-trap device consists of three separate pieces of equipment: the sample purger, the trap, and the desorber. All three pieces are commercially available in an automated unit. Either a Varian Archon Autosampler or a Tekmar ALS2016 in conjunction with a Tekmar LSC2000 concentrator are used at Severn Trent Laboratories Baltimore Trap: VOCARB 3000 (Carbopack B/Carboxen 1000 and 1001). Before initial use, the trap should be conditioned overnight at 270EC by backflushing with an inert gas flow of at least 20 ml/min The desorber should be capable of rapidly heating the trap to 260EC for desorption. The trap should not be heated higher than 300EC. 6.6 Heater: Should be capable of maintaining the purging chamber to within 1EC over a temperature range from ambient to 100EC. 6.7 Syringes: 5 ml and 20 ml gas-tight. 6.8 Volumetric flasks, Class A: 10, 50, 100, 500, and 1,000 ml with a ground glass stopper. 6.9 Microsyringes: 10, 25 and 100 µl needle (Hamilton 702N or equivalent) Balances: Analytical ( ± g accuracy) and Top Loading ( g accuracy).

9 Aromatic Volatile Organics by Gas Chromatography Page 9 of SAFETY AND CHEMICAL HYGIENE The toxicity or carcinogenicity of each reagent used in this method has not been precisely defined; however, each chemical compound should be treated as a potential health hazard, and exposure to these chemicals must be reduced to the lowest possible level by whatever means available. The laboratory maintains a reference file of Material Safety Data Sheets (MSDS) for the chemicals specified in this method. Additional information on laboratory safety is available in the Laboratory Safety Plan and from the Health and Safety Officer. 8.0 STANDARDS AND REAGENTS 8.1 Methanol, CH OH. Purge-and-trap grade or equivalent. Store away from other solvents Stock Standards: Stock solutions are purchased as certified solutions, stored at -10EC to -20EC. and protected from light. Once stock standard ampules are opened, they are stored no longer than 1 month, or sooner if comparison with check standards indicates a problem. 8.3 Secondary Dilution Standards: Using stock standard solutions, prepare secondary dilution standards in methanol, as needed, containing the compounds of interest, either individually or mixed together. Secondary dilution standards should be stored with minimal headspace for the same time period specified in Calibration Standards: Prepare calibration standards in organic-free reagent water from the secondary dilution or stock standards, at the concentrations listed in Table 4. Each standard should contain each analyte for detection by this method (including the surrogate compound). In order to prepare accurate aqueous standard solutions, the following precautions must be observed Rapidly inject the alcoholic standard into the filled volumetric flask or gas tight syringe Mix aqueous standards by inverting the volumetric flask or syringe three times only If the standard is prepared in a volumetric flask, fill the sample syringe from the standard solution contained in the expanded area of the flask (do not use any solution contained in the neck of the flask) Never use pipettes to dilute or transfer samples or aqueous standards Aqueous standards are not stable and should be discarded after one hour, unless properly sealed and stored. The aqueous standards can be stored up to 24 hours, if held in sealed vials with zero headspace. TABLE 4. STANDARD PREPARATION Volume of 200 ppm stock Deionized Reagent Concentration (ul) Water (ug/l) (ml) Surrogate standards: The analyst will monitor both the performance of the analytical system and the effectiveness of the method in dealing with each sample matrix by spiking each sample, LCS, and

10 Aromatic Volatile Organics by Gas Chromatography Page 10 of 13 organic-free reagent blank with the surrogate compound 4-bromofluorobenzene (BFB) at 50 µg/l (water), 50 µg/kg (low soil) and 6250 µg/kg (high soil). 8.6 ICV/LCS: Prepare a second source standard in organic-free reagent water at the concentration of the 50 ug/l using a stock standard from a different manufacturer or, at a minimum, from a different vendor lot for that used to prepare the calibration standards. The ICV/LCS contains each method analyte, including the surrogate compounds. 9.0 CALIBRATION Volatile compounds are introduced into the gas chromatograph using purge-and-trap. Purge-and-trap may be used directly on ground water samples or low-concentration contaminated soils and sediments. For mediumconcentration soils or sediments, methanol extraction is performed prior to purge-and-trap analysis. Gas chromatographic conditions are set to ensure acceptable method performance. 9.1 Calibration: A calibration curve is required for all target compounds, including surrogate compounds. The calibration summary form will show the calibration factors (CF), relative percent standard deviation (%RSD) for all compounds, including surrogates. Establish gas chromatographic operating parameters. Prepare calibration standards using the procedures indicated in Section 8.0. Calibrate the chromatographic system Initial Calibration (IC): For water and medium level soil matrices, the initial calibration is performed at ambient temperature. For low level soils, the initial calibration is performed at 40EC. Each calibration standard is introduced into the gas chromatograph using the same technique that will be used to introduce the actual samples. Tabulate area responses against the mass injected. Average CF is used for quantitation unless the %RSD is greater than 20%. CF = A M where: CF = Calibration Factor A = Total peak area M = Mass injected (in nanograms) If the %RSD criteria for the initial calibration exceeds 20%, a linear regression analysis can be established and used for quantitation Make certain that the instrument response is treated as the dependent variable (y) and the concentration as the independent variable (x). The regression will produce the slope and intercept terms for a linear equation in the form: where: y = mx + b y = Instrument response m = Slope of the line (also called the coefficient of x) x = Concentration of the calibration standard b = The intercept The line must not be forced through the origin. Do not include the origin (0,0) as the sixth point.

11 Aromatic Volatile Organics by Gas Chromatography Page 11 of The regression calculation will generate a correlation coefficient (r) that is a measure of the "goodness of fit" of the regression line to the data. A value of 1.00 indicates a perfect fit. The correlation coefficient 2 must be r$0.990 (r $0.980) The linear regression plot needs to be evaluated to ensure that the y-intercept does not exceed the method reporting limit. If this situation should occur, a new initial calibration may be required Another approach is to elevate the reporting limit to a point equal to or greater than the y-intercept. The analyst must first check the project summary to determine if raising the RL exceeds action levels. This must be approved by the Section Chief, Quality Services Manager, and the Operations Manager prior to reporting the data Initial Calibration Verification (ICV): The working calibration curve must be verified by a standard prepared from a independent source prior to sample analysis. If the average response for all parameters varies from the predicted response by more than +15%, the analysis must be repeated using a fresh calibration standard. If the ICV standard fails again a new calibration curve must be prepared. An ICV must be analyzed each time a new calibration curve is generated Continuing Calibration Verification (CCV): The CCV must be prepared and analyzed at the beginning ending of each analytical batch. If the average response for all parameters varies from the predicted response by more than +15%, a new CCV must be prepared and analyzed. In the event the CCV fails again a new calibration curve must be generated. 9.2 Retention Time Windows: Following successful initial calibration, establish the retention time window (RTW) for each target analyte calculated as the average retention time from the initial calibration standards. The calculated RTW must be within Severn Trent Laboratories Baltimore default window of ± 0.2 min. Confirm that all calibration standards are within the windows. If not, the calibration curve may be updated using the daily calibration. 10. SAMPLE PREPARATION AND ANALYSIS 10.1 Sample Preparation Refer to STL-M-5030A, STL-M-5030B or STL-M-5035 for appropriate preparation procedures Sample Analysis Samples are analyzed in a set referred to as an analytical sequence, as shown in the following table: Injection Description 1 Instrument Blank (IBLK) 2 Calibration Standard (Level 1) 3 Calibration Standard (Level 2) 4 Calibration Standard (Level 3) 5 Calibration Standard (Level 4) 6 Calibration Standard (Level 5) 7 ICV/LCS 8 Method Blank (VBLK) 9 Sample 10 Sample 11 Sample

12 Aromatic Volatile Organics by Gas Chromatography Page 12 of 13 Injection Description No calculated results below the Reporting Limit (RL) are reported unless required by the client. For those projects which require reporting to the MDL, data reported below the RL are qualified as estimated by flagging with J. The sequence should contain a beginning and ending CCV, VBLK, LCS, MS/MSD and as many samples as can be analyzed within the 12 hour period If the sample responses exceed the level of the highest standard from the initial calibration, dilute the sample and reanalyze. The dilution factor is acceptable if the target analyte response is within the upper half of the calibration range, unless a straight analysis has been performed and the analyst can demonstrate no target analytes were unnecessarily diluted out Tentative identification of an analyte occurs when a peak from a sample extract falls within the retention time window. Unless otherwise required by client, project, or program, qualitative confirmation is required: on a second GC column; by GC/MS if concentration permits; or by other recognized confirmation techniques. Confirmation may not be necessary if the composition of the sample matrix is well established by prior analyses Additional information concerning the analytical sequence should be identified in the instrument injection log following STL-SOP Using the calibration procedure (Section 9.1), determine the identity and quantity of each component peak (using equations in Section 10.0) in the sample chromatogram which corresponds to the compounds used for calibration purposes CALCULATIONS 11.1 Aqueous Samples: where: 11.2 Nonaqueous Samples: Concentration (µg/l) = (A)(D) (CF)(V(s)) CF = Average calibration factor from the initial calibration A = Response for the analyte in the sample D = Dilution factor, if no dilution D=1 V(s) = Volume of sample purged in ml Concentration (µg/kg) = (A(x))(D) (CF)(V)(W) where: W = Weight of sample purged or extracted, in grams. V = Volume of methanol extract added to reagent water, in µl.

13 Aromatic Volatile Organics by Gas Chromatography Page 13 of QUALITY CONTROL A(x), CF, and D have the same definition as for aqueous samples when a solid sample is analyzed Initial Demonstration of Precision and Accuracy: Prior to the analysis of samples, each analyst is required to demonstrate the ability to generate data of acceptable bias and precision according to the following procedure. The documentation of this demonstration is included in the analyst s Training Record Four aliquots of the well mixed independent source standard at the concentration of 20 ug/l analyzed by the same procedures used to analyze actual samples Calculate the average recovery (x) in µg/l, and the standard deviation of the recovery (s) in µg/l, for each analyte of interest using the four results. For each analyte compare s and x with the corresponding acceptance criteria for precision and accuracy (Table 6). TABLE 6. INITIAL ACCURACY AND PRECISION CRITERIA(a) Parameter Limit for s (µg/l) Range for x (µg/l) Benzene Chlorobenzene ,2-Dichlorobenzene ,3-Dichlorobenzene ,4-Dichlorobenzene Ethylbenzene Toluene s = Standard deviation of four recovery measurements, in µg/l. x = Average recovery for four recovery measurements, in µg/l If s and x for all analytes of interest meet the acceptance criteria, the system performance is acceptable and analysis of actual samples can begin. If any individual s exceeds the precision limit or any individual x falls outside the range for accuracy, then the system performance is unacceptable for that analyte. The analyst must proceed with corrective action which is to repeat the test only for those analytes that failed to meet criteria. Repeated failure, however, will confirm a general problem with the measurement system. If this occurs, locate and correct the source of the problem and repeat the test for all compounds of interest Quality control requirements and corrective actions for all method quality control are listed in Table SECOND COLUMN CONFIRMATION Any confirmation results which differs form the primary column result by more than 25% must be evaluated by the analyst for integration error and/or measurement bias due to the sample matrix POLLUTION PREVENTION 14.1 Pollution prevention encompasses any technique that reduces or eliminates the quantity or toxicity of waste at the point of generation. Numerous opportunities for pollution prevention exist in laboratory operation. The EPA has established a preferred hierarchy of environmental management techniques that places pollution prevention as the management option of first choice. Whenever, feasible,

14 Aromatic Volatile Organics by Gas Chromatography Page 14 of 13 laboratory personnel should use pollution prevention techniques to address their waste generation. When wastes cannot be feasibly reduced at the source, the Agency recommends recycling as the next best option The quantity of chemicals purchased should be based on expected usage during its shelf life and disposal cost of unused material. Actual reagent preparation volumes should reflect anticipated usage and reagent stability REFERENCES United States Environmental Protection Agency Test Methods for Evaluating Solid Waste. Physical/Chemical Methods. EPA SW-846, 3rd edition, including Update III. U.S. EPA, Washington, D.C.

15 Aromatic Volatile Organics by Gas Chromatography Page 15 of 13 TABLE 7. SUMMARY OF LABORATORY QUALITY CONTROL REQUIREMENTS AND CORRECTIVE ACTION PROCEDURES QC Check Frequency Acceptance Criteria Laboratory Corrective Action Holding time 14 days from sam- Analysis is completed within holding time. Notify client, determine if laboratory to proceed or if client will resample. pling (preserved); 7 days (unpreserved) Initial Calibration & Established initially Initial Calibration average %RSD for all 1. Reanalyze check standard. Calibration curve at 5 concentration analytes is less than <20 %, or use 2. If similar results are obtained, recalibrate instrument. levels, verified daily calibration curve (r >0.990) if %RSD >20%. 3. Evaluate data useability. Reanalyze if data useability is impacted. at mid level 4. Document actions taken in a Nonconformance Record, and in the analytical report Calibration One ICV analyzed Initial Calibration Verification average %D 1. Reanalyze check standard. Verification after each ICAL and must be < +/-15%, Continuing Calibration 2. If similar results are obtained, recalibrate instrument. (ICV, CCV) prior to sample Verification average %D must be < +/-15%. 3. Evaluate data useability. Reanalyze if data useability is impacted. analyses. Verify 4. Document actions taken in a Nonconformance Record, and in the initial calibration analytical narrative. daily at mid level. Method Blank 1 per analytical Concentration is less than the RL for each 1. Determine source of contamination, i.e. instrument, blank water, batch analyte reagents. 2. Take appropriate corrective action and document. 3. Reanalyze or reprepare analytical batch. 4. If samples cannot be reanalyzed or reprepared, qualify data.

16 Aromatic Volatile Organics by Gas Chromatography Page 16 of 13 TABLE 7. SUMMARY OF LABORATORY QUALITY CONTROL REQUIREMENTS AND CORRECTIVE ACTION PROCEDURES QC Check Frequency Acceptance Criteria Laboratory Corrective Action LCS 1 per analytical Values are within laboratory control limits 1. Validate instrument parameters, sensitivity and linearity. Correct batch for precision and accuracy. problems and document. 2. Validate standard and LCS preparation. Correct any problems and document. 3. Evaluate against project specific DQOs and report data if there is not impact on data usability. 4. If data is not usable, reprepare and reanalyze the method blank, LCS and all field samples in the batch. 5. If repreparation of samples is not possible, qualify data, and note in the report narrative. 6. Document actions taken in a Nonconformance Record, and in the analytical narrative. Surrogate spike All laboratory QC Surrogate recoveries are within laboratory 1. Examine all QC (including but not limited to LCS, MB). and field samples. limits. 2. If surrogate in LCS and/or MB is out-of-control, check quantitation. If quantitation is correct reanalyze. 3. If similar results are obtained from reanalysis, obtain fresh, verified surrogate solution and reanalyze the analytical batch. 4. If samples cannot be reprepared, qualify data. 5. If surrogate spike in LCS and MB are acceptable but out-of- control for samples, validate preparation of samples. If no errors or problems are discovered for sample preparation, qualify data. 6. If errors are discovered in preparation of samples, reprepare QC samples and all affected samples. 7. Document actions taken in a Nonconformance Record, and in the analytical narrative.

17 Aromatic Volatile Organics by Gas Chromatography Page 17 of 13 TABLE 7. SUMMARY OF LABORATORY QUALITY CONTROL REQUIREMENTS AND CORRECTIVE ACTION PROCEDURES QC Check Frequency Acceptance Criteria Laboratory Corrective Action MS/MSD 1 set per analytical Values are compared to the laboratory LCS 1. If the MS/MSD recoveries are outside the LCS limits and the LCS batch control limits for precision and accuracy. recoveries are acceptable, the method is considered in-control and a matrix bias is assumed. 2. If the MS/MSD and LCS recoveries are outside the LCS limits, the method is considered out-of-control. The entire analysis batch should be reanalyzed. Note: High recoveries, indicating a positive bias, may yield useful data if the specific target analyte(s) is not detected above the reporting limits. Notify the Section Chief or Division Manager if this situation should occur. 4. If reanalysis is not possible, qualify data. 5. Document actions taken in a Nonconformance Record, and in the analytical narrative.