ALLOWAY STANDARD OPERATING PROCEDURES FOR METHOD 504.1/8011

Transcription

1 ALLOWAY STANDARD OPERATING PROCEDURES FOR METHOD 504.1/8011 1,2-DIBROMOETHANE (EDB) AND 1,2-DIBROMO-3-CHLOROPROPANE (DBCP) IN WATER BY MICROEXTRACTION AND GAS CHROMATOGRAPHY SOP #: Revision 1.1, 1995 & SW Originator: Section Supervisor: QA Manager Date: Date: Date: Page 1 of 23

2 Section 1.0 Scope and Application 1.1 This is a gas chromatographic (GC) method applicable to the determination of the following compounds in ground water and finished drinking water. ANALYTE 1,2-Dibromoethane 1,2-Dibromo-3-chloropropane 1.2 When this method is used to analyze unfamiliar samples for any or all of the analytes above, analyte identifications must be confirmed by at least one additional qualitative technique. Section 2.0 Summary of Method mL of sample are salted with approximately 6 g of baked sodium chloride and are extracted with 2-mL hexane. Two L of the extract are then injected into a gas chromatograph equipped with a linearized electron capture detector for separation and analysis. Aqueous calibration standards are extracted and analyzed in an identical manner to the samples in order to compensate for possible extraction losses. Section 3.0 Definitions 3.1 Acceptance Criteria specified limits placed on characteristics of an item, process, or service defined in required documents. 3.2 Analytical Batch composed of prepared environmental samples which are analyzed together as a group. It can include prepared sample originating from various environmental matrices and cannot exceed 20 samples. 3.3 Calibration to determine, by measurement or comparison with a standard, the correct value of each scale reading on a meter, instrument, or other device. The levels of the applied calibration standard should bracket the range of planned or expected sample measurements. 3.4 Calibration Curve the graphical relationship between the known values, such as concentrations, of a series of calibration standards and their instrument response. Page 2 of 23

3 3.5 Calibration Standard (CAL) -- A solution prepared from the primary dilution standard solution. The CAL is used to calibrate an instrument. 3.6 Field Blank or Trip Blank blank prepared in the field or laboratory by filling a clean container with pure de-ionized water and appropriate preservative, if any, for the specific sampling activity being undertaken. 3. High Quality Pure Reagent Water water in which no target analytes or interferences are detected as required by the analytical method. 3.8 Holding Times (Maximum Allowable Holding Times) the maximum times that samples may be held prior to analysis and still be considered valid or not compromised. 3.9 Internal Standard a known amount of standard added to a test portion of a sample as a reference for evaluating and controlling the precision and bias of the applied analytical method Laboratory Reagent Blank (LRB) -- An aliquot of reagent water that is treated exactly as a sample including exposure to all glassware, equipment, solvents, reagents, internal standards, and surrogates that are used with other samples. The LRB is used to determine if method analytes or other interferences are present in the laboratory environment, the reagents, or the apparatus Laboratory Fortified Blank (LFB) -- An aliquot of reagent water to which a known quantity of the method analyte is added in the laboratory. The LFB is analyzed exactly like a sample, and its purpose is to determine whether the method is in control, and whether the laboratory is capable of making accurate and precise measurements at the required method detection limit Laboratory Performance Check Solution (LPC) -- A solution of method analytes, surrogate compounds, and internal standards used to evaluate the performance of the instrument system with respect to a defined set of method criteria Matrix the component or substrate that contains the analyte of interest Matrix Spike (MS) or Laboratory Fortified Matrix (LFM) a sample prepared by adding a known mass of target analyte to a specified amount of matrix sample for which an independent estimate of target analyte concentration is available. Used to determine the effect of the matrix on a method s recovery efficiency. The background concentration of the analyte in the sample matrix must be determined in a separate aliquot and the measured value in the LFM corrected for background concentration. Page 3 of 23

4 3.15 Matrix Spike Duplicate (MSD) or Laboratory Fortified Matrix Duplicate (LFMD) a second replicate of spike prepared in the laboratory and analyzed to obtain a measure of the precision of the recovery for each analyte Primary Dilution Standard Solution (PDS) - A solution of several analytes purchased from a commercial source and diluted as needed to prepare calibration solutions and other needed analyte solutions. 3.1 Procedural Standard Calibration - A calibration method where aqueous calibration standards are prepared and processed (e.g., purged, extracted, and/or derivatized) in exactly the same manner as a sample. All steps in the process from addition of sampling preservatives through instrumental analyses compensates for any inefficiencies in the processing procedure Quality Control the overall system of technical activities whose purpose is to measure and control the quality of a product or service so that it meets the needs of users Raw Data any original factual information from a measurement activity or study recorded in a laboratory notebook, worksheets, records, memoranda, notes, or exact copies thereof that are necessary for the reconstruction and evaluation of the report activity Reference Method a method of known and documented accuracy and precision issued by an organization recognized as competent to do so Standard Operating Procedure (SOP) a written document which details the method of an operation, analysis or action whose techniques and procedures are thoroughly prescribed and which is accepted as the method for performing certain routine or repetitive tasks Stock Standard Solution -- A concentrated solution containing a single certified standard that is a method analyte, or a concentrated solution of a single analytes prepared in the laboratory with an assayed reference compound. Stock standard solutions are used to prepare primary dilution standards Surrogate a substance with properties that mimic the analyte of interest. It is unlikely to be found in environment samples and is added to them for quality control purposes. Calculated as percent recovery. Page 4 of 23

5 Section 4.0 Interferences 4.1 Method interferences may be caused by contaminants in solvents, reagents, glassware, and other sample processing apparatus that lead to anomalous peaks or elevated baselines in liquid chromatograms. The LRB is used as a tool to monitor for the presence of interferences. 4.2 Glassware used for this procedure includes pre-cleaned volatile vials (VOA vials) and pre-cleaned 2 ml auto-sampler vials. 4.3 Interfering contamination may occur when a sample containing low concentrations of compounds is analyzed immediately after a sample containing relatively high concentrations of compounds. Syringes and injection port liners must be cleaned carefully or replaced as needed. After analysis of a sample containing high concentrations of compounds, a solvent blank or an LRB is analyzed to ensure that accurate values are obtained for the next sample. If suspicion of carryover exists, reanalysis of the affected samples is performed. 4.4 Samples and standards must be contained in the same solvent to ensure chromatographic comparability. 4.5 Current column technology suffers from the fact that EDB at low concentrations may be masked by very high levels of dibromochloromethane (DBCM), a common disinfection by-product of chlorinated drinking waters. Section 5.0 Safety 5.1 The toxicity or carcinogenicity of each chemical and reagent used in this method has not been precisely defined. However, each one must be treated as a potential health hazard, and exposure to these chemicals should be minimized. Each analyst is responsible for adherence to the procedures outlined in the Alloway Chemical Hygiene Plan. 5.2 Some method analytes have been tentatively classified as known or suspected human or mammalian carcinogens. Pure standard materials and stock standard solutions of these compounds should be handled with suitable protection to skin, eyes, etc. 5.3 Safety glasses, gloves, and lab coats must be worn when handling samples and solvents. Safety glasses must be worn when handling glassware and Page 5 of 23

6 chromatographic columns. Safety glasses must be worn when handling equipment within the laboratory. 5.4 EDB and DBCP have been tentatively classified as known or suspected human or mammalian carcinogens. Pure standard materials and stock standard solutions of these compounds should be handled accordingly. Section 6.0 Equipment and Supplies 6.1 Sample Bottle - 40 ml VOA vials (pre-cleaned) fitted with Teflon lined screw cap. 6.2 Autosampler vials - Autosampler vials (pre-cleaned) suitable for use on the appropriate autosampler. 6.3 Micro Syringes 10, 25 and 100 l gas-tight micro-syringes. 6.4 Pipetters and 8.0 ml transfer pipetters. 6.5 Gas Chromatograph - Analytical system complete with temperature programmable GC suitable for use with capillary columns and all required accessories including syringes, analytical columns, gasses, detector and data collection Column 1 RTX-CLPesticidesII 30-m x 0.53-mm I.D. x 0.42-m Film (Restek Catalog Number 11340), or equivalent Conditions Oven - 50C, 4 degrees C/min to 60 degrees C/min hold 6 min, then 10 degrees C/min to 145 degrees C then 20 degrees C/min to 200 degrees C and hold 2.25 minutes. Inlet Temperature 0C, 5 degrees C/min to 110 degrees C, then 10 degrees C/min to 180 degrees C, then 15 degrees C/min to 225 degrees C and hold for 4 minutes. Detector C Injector 2.5 l Flow electronic pressure control set at 3.0 psi. Page 6 of 23

7 6.5.2 Column 2 RTX CLPesticides 30m x 0.53 mm I.D. x 0.50 m Film (Restek Catalog Number 11140), or equivalent Conditions Oven - 50C, 4 degrees C/min to 60 degrees C hold 6 min, then 10 degrees C/min to 145 degrees C then 20 degrees C/min to 200 degrees C and hold 2.25 minutes. Inlet Temperature 0C, 5 degrees C/min to 110 degrees C, then 10 degrees C/min to 180 degrees C, then 15 degrees C/min to 225 degrees C and hold for 4 minutes. Detector C Injector 2.5 l Flow electronic pressure control set at Detector - Electron capture. This detector has been proven effective in the analysis of fortified reagent and artificial ground waters. Section.0 Reagents and Calibration Standards.1 Hexane - Pesticides quality or better..2 Methanol - Purge and Trap Grade, or equivalent.3 Sodium Chloride - Baked for 0.5 hours at 400C.4 Stock Standard Solution (200 ug/ml) - Ultra Scientific, DWN-504, or equivalent.5 Calibration Spike Standard 50-ug/L. See Alloway s Reagent traceability software for the preparation of this spiking standard..6 Second Source Standard (200 ug/ml) Restek catalog number or equivalent.. Laboratory Fortified Blank (LFB) and Laboratory Fortified Sample Matrix (LFM) solution - 50-ug/L. See Alloway s reagent traceability for the preparation of the 50-µg/L spike solution. Page of 23

8 .8 High Quality Reagent Water Laboratory DI water meets method blank requirements. Section 8.0 Sample Collection, Preservation, Shipment, and Storage 8.1 Sample Collection Replicate field reagent blanks (FRB) must be handled along with each sample set, which is composed of the samples collected from the same general sampling site at approximately the same time. At the laboratory, fill a minimum of two sample bottles with reagent water, seal, and ship to the sampling site along with the sample bottles. Wherever a set of samples is shipped and stored, it must be accompanied by the FRB Collect all samples in 40 ml VOA bottles into which 3 mg of sodium thiosulfate crystals have been added to the empty bottles just prior to shipping to the sampling site. Alternatively, 5 L of freshly prepared sodium thiosulfate solution (0.04 g/ml) may be added to empty 40 ml VOA bottles just prior to sample collection When sampling from a water tap, open the tap and allow the system to flush until the water temperature has stabilized (usually about 10 minutes). Adjust the flow to about 500 ml/min and collect samples from the flowing stream When sampling from a well, fill a wide-mouth bottle or beaker with sample, and carefully fill 40 ml VOA bottles. 8.2 Sample Preservation and Storage The sample must be iced or refrigerated at 6C or less away from light from the time of collection until extraction Sodium thiosulfate must be added to avoid the possibility of reactions which may occur between residual chlorine and indeterminate contaminants present in some solvents, yielding compounds which may subsequently interfere with the analysis. The presence of sodium thiosulfate will arrest the formation of DBCM (see Section 4.5). Method 8011 samples should be acidified to a ph < 2.0 to avoid the possibility of microbial degradation which may periodically affect these analytes contained in other ground water matrices. Page 8 of 23

9 8.2.3 Holding Times - Preservation study results indicate that the analytes present in the samples are stable for 14 days when stored under these conditions. All samples must be extracted and analyzed within 14 days of collection and when necessary, extracts may be stored in tightly capped vials at 6 degrees C for up to 24 hours. Section 9.0 Calibration and Standardization 9.1 Establish GC operating parameters equivalent to those indicated in Section 6.5. The GC system is calibrated using the external standard technique. 9.2 External Standard Calibration Procedure Prepare seven standards by adding 5, 10, 20, 30, 40, 50, 60 ul of the stock solution (0.05-µg/L) to 35 mls of high quality reagent water. Curve concentrations range from , , , , 0.051, 0.014, and ug/l Each day, extract and analyze each calibration standard according to the procedure (Section 11). Tabulate response (peak area) against concentration for each compound. Calculate the response factor (RF) for each analyte and surrogate. Use a linear or quadratic regression without forcing the curve through zero. Regression curve fits >0.995 should be appropriate. Average Response Factor must be less than 20% RSD for EPA Method Samples (<10% for EPA Method 8011). 9.3 Continuing Calibration Verification (CCV) A calibration standard at mid concentration containing all of the compounds must be analyzed every 10 samples during analysis. For each compound the calculated value must be within 30% of the working value. If not corrective action must be taken and the check standard re-analyzed. If the reanalyzed CCV meets the requirements of 0-130% recovery then analysis may proceed. If the reanalyzed CCV is high (>130%) and the results of samples are below the reporting levels, the results of the samples can be reported without qualification. If the reanalyzed CCV is high (>130 %) indicating a high bias, and the results of samples are detected at or above the reporting limit the samples need to be reanalyzed following the acceptance of a new calibration curve or a completed corrective action. If the reanalyzed CCV is low (<0%) indicating a low bias, results for samples exceeding a regulatory limit may be reported and Page 9 of 23

10 qualified using the statement: The CCV was below the lowest limit indicating a low bias. This result exceeds the regulatory limit and is considered a reportable value under the TNI standards. If the reanalyzed CCV is biased low (<0%) and the results of the samples do not exceed a regulatory limit then the samples must be reanalyzed after acceptance of a new calibration curve The CCV must be from a different source than that of the standard used in the initial calibration curve. 9.4 Instrument Performance - Check the performance of the entire analytical system daily using data gathered from analyses of reagent water blanks, standards, and the QC check standard Significant peak tailing must be corrected. Tailing problems are generally traceable to active sites on the GC column, improper column installation, or the operation of the detector Check the precision between replicate analyses. A properly operating system should perform with an average relative standard deviation of less than 10%. Poor precision is generally traceable to pneumatic leaks, especially at the injection port. Section 10.0 Quality Control 10.1 Minimum quality control (QC) requirements are initial demonstration of capability and detection limit studies and an ongoing analysis of laboratory reagent blanks (LRB), laboratory performance check solutions (LPC), laboratory fortified sample matrix (LFM), laboratory fortified blanks (LFB), and quality control samples (QCS) to evaluate and document data quality. Ongoing data quality checks are compared with established performance criteria to determine if the results of analyses meet the performance characteristics of the method Initial Demonstration of Capability Prepare four samples at a concentration of g/L for each analyte. Analyze each sample according to procedures beginning in Section Calculate the average concentration (X) in g/l, and the standard deviation of the concentration(s) in g/l, for each analyte. %RSD of the four samples must be <20%. Page 10 of 23

11 For each analyte the recovery value for all four of these samples must fall in the range of 30% of true value. For those compounds that meet the acceptable criteria, performance is considered acceptable and sample analysis may begin. For those compounds that fail these criteria, the instrument should be optimized and this procedure must be repeated using fresh samples until satisfactory performance has been demonstrated The initial demonstration of capability is used primarily to preclude a laboratory or analyst from analyzing unknown samples via a new, unfamiliar method prior to obtaining some experience with it Method Detection Limit For each analyte, determine the method detection limit (MDL). Prepare a minimum of seven LFB s at a low concentration. Extract and analyze each replicate according to Section The LFB s should be prepared over a period of several days so that day to day variations are reflected in precision measurements. The standard deviation of the average of seven results for each analyte is then multiplied by to obtain the calculated MDL. The reporting limit check standard when analyzed daily may be used to calculate the MDL Laboratory Reagent Blanks (LRB) - With each batch, the analyst must demonstrate that all glassware and reagent interferences are under control. The LRB consists of reagent water extracted as with the samples. Each time a set of samples is extracted or reagents are changed, a LRB must be analyzed. If a target analyte is detected but falls below the reporting limit, then samples may be reported. If an analyte of interest is detected in the LRB at or above the reporting limit, samples that have results below the reporting limit can be reported with qualification. Sample results that are 10 times higher than the LRB can be reported with the following qualifying statement: Analyte detected in the Method Blank is 1/10 of the amount detected in this sample. Evaluate data accordingly. If the sample result is not 10 times higher than the result in the method blank then the samples should be reanalyzed or if reported the results must be qualified with the following statement: Analyte detected in the Method Blank is 1/10 of the amount detected in this sample. Evaluate data accordingly. If within the retention time window of any analyte of interest the LRB produces a peak that would prevent the determination of that analyte, determine the source of contamination and eliminate the interference before processing samples. Page 11 of 23

12 10.5 Assessing Laboratory Performance - Laboratory Fortified Blank (LFB) The laboratory must analyze at least one laboratory fortified blank (LFB) sample with every 10 samples or one per sample set (all samples extracted within a 24 hour period) whichever is greater. Calculate the accuracy as percent recovery (X). The recovery (X) should be between 0% and 130% of the expected value. If the LFB meets limits the results can be reported. If the initial LFB fails the 0-130% recovery criteria then it can be analyzed a second time. \ If the reanalyzed LFB meets requirements then analysis may proceed. If the reanalyzed LFB is exceeded high (>130%) and the results of the samples are below the reporting level, then the results can be reported using the following qualification statement: The LFB was above the upper limit indicating a high bias. This non-detect result is not affected by the high bias of the LFB. If the reanalyzed LFB is exceeded high (>130%) and the results of the sample are detected at or above the reporting level then the samples need to be re-analyzed following acceptance of a new calibration curve or following corrective action. If the reanalyzed LFB is exceeded low (<0%), indicating a low bias, then the results for samples that exceed a regulatory limit may be reported using the following qualifying statement: The LFB was below the lower limit indicating a low bias. This sample result exceeds the regulatory limit and is considered reportable under the TNI standards. If the reanalyzed LFB is exceeded low, indicating a low bias then the results for samples that do not exceed a regulatory limit need to be reanalyzed following acceptance of a new calibration curve or following corrective action Assessing Analyte Recovery - Laboratory Fortified Sample Matrix (LFM) The laboratory must add a known concentration to a minimum of 10% of the routine samples or one sample concentration per set, whichever is greater. The concentration of g/l will be used for the LFM. Results of these analyses should have a recovery of 65%-135% of the expected value. If the recovery fall outside of the acceptable limits, report the sample result with the following qualification statement: The matrix spike fell outside method limits (biased high) or (biased low). The result for this sample should be evaluated accordingly. Page 12 of 23

13 10. Assessing Analyte Precision Laboratory Fortified Sample Matrix Duplicate (LFSMD) / Sample Duplicate (SD) If the sample is not expected to contain target analytes then a LFSMD is performed on at least 10% of the samples. If the sample is expected to contain target analytes then a sample duplicate is used If the LFSMD option is used then the corrected recovery must be the same as in Section The %RPD on a Sample duplicate and the LFSMD should be < 10%.If the relative percent difference (RPD) is results can be reported If the %RPD is not report only the result of the sample used for the duplicate with the following statement: The duplicate fell outside method limits and the result should be evaluated accordingly Reporting limit check (RLC) The RLC is extracted following same procedures as samples. One RLC is extracted every extraction batch to make sure that the equipment is capable of seeing analytes below the reporting limits. The check is analyzed using a µg/l concentration. The recovery of the RLC should be 60%-140% of the expected value. If recovery is outside of these limits, corrective action must be taken and the problem resolved prior to the analysis of any samples It is required that a laboratory periodically establish its ability to distinguish Dibromochloromethane (DBCM) from EDB once per year. To do this start with reagent water that is fortified at 50 g/l DBCM (Stock Standard can be obtained from VOC analyst), and during sample extraction fortify this sample at the Reporting Limit for EDB, and analyse. There should be no interferences between DBCM and EDB and the recovery should be % of the expected value. Section 11.0 Analytical Procedures 11.1 Micro-extraction and Analysis Remove samples and standards from storage and allow them to reach room temperature Remove container cap if in place. Remove approximately 6.2 ml from the 40 ml VOA vials and weigh, record as wet weight. Page 13 of 23

14 From the 6.2 mls removed from the 40 ml vial, check the ph and residual chlorine levels. Record both values on the extraction benchsheet. Chlorine level should be non-detect. (for method 8011, ph should be <2.0.) Add approximately 6 grams of baked sodium chloride Fortify Calibration standards with the appropriate amount of the 50-µg/L calibration stock standard solution (5, 10, 20,30,40,50, and 60-µL) Fortify CCVs, LFB, LFM, LFMD with 40-µL of the stock standard solution Add 2.0 ml of hexane with 2 ml pipetter. Recap and shake vigorously by hand for 1 minute. Allow the water and hexane layers to separate. (If stored at this stage, keep the container upside down) Remove cap and carefully transfer hexane into the autosampler vial using a disposable glass pipette Transfer the autosampler vials to the autosampler and inject 2.5 L into the gas chromatograph Determination of Sample Volume Weigh empty 40 ml VOA vial and record weight Subtract the weight of empty vial from wet weight to get sample weight/volume. The volume correction factor = 35/sample volume Setting up the Sequence On computer, pull down Sequence Scroll and choose New Sequence Pull down Sequence Scroll and choose Save Sequence As. Save the sequence with the date that the run is started Pull down Sequence Scroll and choose Sequence Parameters. Change the subdirectory to the date that is being used for the sequence One the computer, pull down Sequence Scroll and choose Sequence Table From the prep sheets, correctly type in each standard, sample and other information into the sequence table to meet quality control requirements. Page 14 of 23

15 Pull down the sequence scroll and choose Print Sequence. Click in the boxes in front of the sequence parameters, method, and injection port. Choose print and make two copies Load all appropriate vials into their correct positions on the autosampler tray using the printed sequence log Prepare instrument for analysis When all samples are loaded and the instrument is ready, choose Start Sequence NOTE: The vials must be recapped after being pierced if the vial will be re-injected for subsequent confirmation analysis Gas Chromatography Section 6.5 summarizes the recommended operating conditions for the GC Calibrate the system daily as described in Section Inject 2.5 L of the sample extract. Record the resulting peak size in area units If the response for the peak exceeds the working range of the system, dilute the extract and reanalyze Reviewing Data Load Method If a curve was run, choose the correct curve for the method. Work the curve according to Section 9 to make sure that it meets all criteria. If all criteria is met, save the new curve Examine all check standards and quality control samples before any samples to ensure that the data is reportable. Use manual integrations if necessary (printing a before and after copy and including the reason code, date, and initials) Load Data File Page 15 of 23

16 After Data File is loaded, all samples will be listed on the left-hand side of the box. Double click on each sample to pull it up on the screen. If a sample is clean, print only a copy from the column that was used for the check standards. If a target compound is detected, copies from both columns must be printed. Page 16 of 23

17 11.6 Identification of Analytes Identify a sample component by comparison of its retention time to the retention time of a reference chromatogram. If the retention time of an unknown corresponds, within limits, to the retention time of a standard compound on both columns, then identification is considered positive The width of the retention time window used to make identifications should be based upon measurements of actual retention time variations of standards over the course of a day. Three times the standard deviation can be used to calculate a suggested window size for a compound. However, the experience of the analyst should weigh heavily in the interpretation of chromatograms. Section 12.0 Calculations and Quantitative Analysis 12.1 Provided the GC data system has been properly calibrated, the results as obtained from the data system should be used to calculate the concentration of the sample. Use the following formula to calculate the concentration: C V F C DF 1 V I Where: Response Factor (RF) C 1 = Concentration from instrument (g/l) V F = Final Volume of Extract DF = Dilution factor C = Concentration in µg/l VI = Volume of sample in ml RF A s Cis A C is s Where: A s = Response for parameter in standard A is = Response for internal standard in standard C is = Concentration (µg/l) of internal standard C s = Concentration (µg/l) of parameter Page 1 of 23

18 Mean Response Factor (RF) RF RFi n Where: RF i = individual Response factor (i n) Soil Concentration (µg/kg) example C g kg A x Is Vt A RFV W D is i s Where: A x = Area of compound of interest RF = Response factor V i = Volume of extract added for purging D = Dilution factor W s = Weight of sample in grams V t = Volume of total extract A is = Area of internal standard I s = Internal standard conc Section 13.0 Data Assessment 13.1 The primary analyst bears the responsibility of producing accurate data. A documented review is performed that includes a check of the following parameters: Calibration verification QC criteria Calculation checks Data entry using the LIMS worksheet Review of all data to ensure proper peak integration The initial data review is documented on a checklist that is initiated and dated by the primary analyst. A secondary review must be performed by an individual trained to the standard operating procedure. The specific procedures for data review can be found in Alloway s data review and manual integration SOPs Data qualifiers are used whenever deviations occur while analyzing the samples. The qualifiers are included on the Certificate of Analysis that is presented to the client. Qualifiers include: samples that were not properly preserved, failed surrogate recovery, failed LFM recovery, qualified due to LRB contamination, estimated or elevated reporting limit due to sample matrix interference, calibration failure (high bias) but sample was <RL for the compound. Page 18 of 23

19 13.3 If acceptance limits are not met corrective actions are taken as described in Alloway s Corrective Action SOP. Section 14.0 Report Generation 14.1 A report is generated after each analysis run is complete. The report includes the US EPA Method number, sample identification, date acquired, acquisition method, date processed, processing method, analyst s name, chromatogram and quantitative results. If any manipulation is performed, the result is saved and another report is printed and added to the original. Section 15.0 Pollution Prevention and Waste Management 15.1 (For information about pollution prevention that may be applicable to laboratory practices, consult Less is Better: Laboratory Chemical Management for Waste Reduction available from the American Chemical Society s Department of Government Relations and Science Policy, th Street N.W., Washington, D.C ) 15.2 ( The Waste Management Manual for Laboratory Personnel, also available from the American Chemical Society at the address above.) 15.3 It is the laboratory s responsibility to comply with the requirements as stated in the Alloway Chemical Hygiene Plan for waste disposal. Section 16.0 References 16.1 EPA Method 504.1, Revision 1.1, Supplement III, 1995 Version, 1,2- Dibromoethane (EDB) and 1,2-Dibromo-3-Chloropropane (DBCP) In Water By Microextraction And Gas Chromatography, Environmental Monitoring Systems Laboratory, Office of Research and Development, USEPA, Cincinnati, Ohio 45268, plus subsequent updates SW-846 Method 8011 plus subsequent updates. Section 1.0 Revision History 1.1 Revision 3 issued to update calibration standard concentrations, add glassware preparation procedures, modify format, remove ATEL/Aqua Tech references and add revision history section. Page 19 of 23

20 1.2 Revision 4 issued to include Sections 6,, 9.2 (differentiated the %RSD criteria between (<20%) and 8011 (<10%), , Removed single point calibration option, reworked Section 11, and added Section 18 QC acceptance criteria, added 10.9 demonstrated the ability to distinguish DBCP from EDB. 1.3 Revision 5.0 issued to update section 9.0 Calibration and Standardization. Section CCV was moved to section 9.3. Added section 9.4 Instrument Performance. Modified and expanded Section 10.0 Quality Control. Added ph and residual chlorine checks to section Revision 6 issued to add section to recap vials after being pierced if additional injections are deemed necessary, to add last sentence to section Revision issued 3/9/15. Revisions include updates to and preservation check limits. Updated instrument conditions in sections and Section 10.8 rewritten to reflect section 9.6 of EPA Method. Updated format. Page 20 of 23

21 Section 18.0 Data Assessment and Acceptance Criteria for Quality Control Measures SOP Reference Requirement Specification and Frequency Acceptance Criteria Section Section Initial Calibration Continuing Calibration Verification (CCV) Use external standard calibration technique to generate an average RRF, first or second order calibration curve only. Verify initial calibration by analyzing a calibration verification standard (second source) at the beginning of an analytical run, after every 10 samples, and at the end of the analytical run. When average response is used, the %RSD must be less than 20% for Method and < 10% for When first or second order regression is used, the correlation coefficient must be greater than A minimum of 5 standards are required for a linear regression. A minimum of 6 standards is required for second order regression. If criteria are not met corrective action is required such as injection port maintenance, new column, and/or recalibration. If Average response is used for the calibration then the response of the analyte should be ± 30% of the average response in the curve. If first or second order regression is used, then the recovery should be ±30% of the true value. 1. If the recovery is below criteria, then the results for the analysis must be considered invalid. 2. If the recovery is above criteria, and there are NO detections in the sample then the results can be reported with a qualifier, otherwise the results should be considered invalid. Page 21 of 23

22 Section 10.8 Reporting Limit Standard (RLC). Daily, prior to the analysis of field samples. The recoveries of the analytes should meet the criteria %, if the recovery is high and no target analytes are detected in the sample then the results can be reported. If the recovery is low then the system does not meet the required sensitivity and analysis cannot proceed until corrective action is taken to restore system sensitivity. Section 10.4 Section 10.5 Laboratory Reagent Blank / Method Blank (LRB) Laboratory Fortified Blank (LFB) Daily, or with each extraction batch of up to 10 samples (1 in 10), whichever is more frequent. Daily, or with each extraction batch of 10 samples or at a rate of 1 in 10 samples Demonstrate that all target analytes are below the PQL, and confirm that possible interferences do not prevent quantification of method Analytes. If target analytes are detected in the method blank then extraction must be considered invalid if the analytes are detected in the samples. Results of LFB analyses at medium and high fortifications should be 0-130% of the true value for each analyte. 1. If the recovery is below method criteria. Then the results for that extraction batch should be considered invalid. 2. If the recovery is above criteria, and there are NO detections in the sample then the results can be reported with a qualifier, otherwise the results should be considered invalid. Page 22 of 23

23 Section 10.6 Section 10. Section Section Laboratory Fortified Sample Matrix (LFSM) Laboratory Fortified Sample Matrix Duplicate (LFSMD) or Field Duplicates (FD) Sample Holding Time Extract Holding Time Analyze one LFSM per analysis batch (10 samples or less) fortified with method analytes at a concentration close to but greater than the native concentration. Calculate LFSM recoveries. Extract and analyze at least one FD or LFSMD with each extraction batch (10% samples or less). A LFSMD may be substituted for a FD when the frequency of detects are low. Calculate RSDs. 14 days with appropriate preservation and storage 24 Hours with appropriate preservation and storage Recoveries that are not within % of the fortified amount may indicate a matrix effect and must be qualified. Target analyte RSDs for the LFMD or FD should be <10%. If the criteria are greater than 10% then the greater of the two results are reported and may indicate matrix effect and must be qualified. Sample results are valid only if samples are extracted within sample hold time. Sample results are valid only if extracts are analyzed within extract hold time. Page 23 of 23