Analysis of Selected Fumigants in Water by Microextraction and GC-ECD

Effective Date: 10/25/2010 Revision Date: 10/25/2010 Revision Author: A. Niculescu GC-018-3.15

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Standard Operation Procedure for:

ANALYSIS OF SELECTED FUMIGANTS IN WATER BY MICROEXTRACTION AND GAS CHROMATOGRAPHY WITH ELECTRON

CAPTURE DETECTION (GC/ECD)

DEPARTMENT OF ENVIRONMENTAL PROTECTION CHEMISTRY SECTION

TALLAHASSEE FLORIDA


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CONTENTS 1. SCOPE AND APPLICATION 2. SUMMARY OF THE METHOD 3. INTERFERENCES 4. DEFINITIONS 5. APPARATUS AND EQUIPMENT 5.1. Gas Chromatograph 5.2. Data System 5.3. Gases 5.4 Glassware 6. REAGENTS AND CHEMICALS 6.1. Solvents 6.2. Neat standards 6.3. D.I. water 6.4 Stock and intermediate standards 6.5. Working standard solutions 6.6. Quality Control Check Standards 7. SAMPLE COLLECTION, PRESERVATION, AND HANDLING 8. SAMPLE PREPARATION PROCEDURE 9. GENERAL DESCRIPTION OF GC/ECD ANALYSIS 9.1 Pre-Run GC Maintenance 9.2 Summary of GC/ECD Analysis 9.3 Instrument Initial Calibration 9.5 Continuing calibration 9.4 Analysis Run Sequence 9.5 Data Processing / Reporting 9.6 Reporting results in DEP LIMS 10. QUALITY CONTROL

11. METHOD PERFORMANCE 12. DATA ARCHIVAL 12. SAFETY 13. POLLUTION PREVENTION 14. REFERENCES 14. APPENDIXES


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1. SCOPE AND APPLICATION

1.1. This method is applicable to the determination of 2 organochlorinated fumigants in water

as listed in Table 1. Method Detection Limits and Practical Quantitation Limits yielded by this method are also provided in Table 1.

1.2. This method is based on EPA method 504. Laboratory Information Management System

(LIMS) test: W-FUM.

1.3. This Standard Operation Procedure is restricted to use by an analyst experienced in the use of a gas chromatograph, in the interpretation of gas chromatograms, and in the use of appropriate computer programs. The minimum qualifications required are: B.S. in Chemistry or Biochemistry with minimum one year of professional chemical

or biochemical experience Knowledge of principles and practice of gas chromatography Ability to perform basic laboratory mathematics Knowledge of EZChrom Chromatography Software, TARGET Chromatography

Software and DEP LIMS.

2. SUMMARY OF THE METHOD

2.1. Thirty five mL of sample are extracted with 2 mL of hexane. Two uL of the extract is injected and analyzed using a Gas Chromatograph (GC) equipped with two capillary dissimilar GC columns and two Electron Capture Detectors (ECDs) to provide confirmatory analyses for all positive hits. Aqueous calibration standards are extracted and analyzed in an identical manner as the samples in order to compensate for possible extraction losses. Surrogate is not available.

3. INTERFERENCES Method interferences may be caused by contaminants in solvents, reagents, glassware, and other sample processing hardware that lead to discrete artifacts and/or elevated baselines in gas chromatograms. All of these materials must routinely demonstrate to be free from interferences under the conditions of the analysis by running laboratory reagent blanks as described in Section 10. Glassware must be scrupulously cleaned. Clean all glassware as soon as possible after use by rinsing with the last solvent used in it. Solvent rinsing should be followed by detergent washing with hot water, and rinses with tap water and distilled water. The glassware should then be drained dry, and heated in a muffle furnace at 400 C for 15-30 minutes. Some thermally stable materials may not be eliminated by this treatment. Solvent rinses with acetone and pesticide quality hexane may be substituted for the muffle furnace heating. Volumetric glassware should not be heated in a muffle furnace. After drying and cooling, glassware should be sealed and stored in a clean environment to prevent any accumulation of dust or other contaminants. Store inverted or capped with aluminum foil. The use of high purity reagents and solvents helps to minimize interference problems. Purification of solvents by distillation in all-glass systems may be required. Interferences by phthalate esters can pose a major problem when using the electron capture detector. These compounds generally appear in the chromatogram as large late eluting peaks. Common flexible plastics contain varying amounts of phthalates. These phthalates are easily extracted or leached from such materials during laboratory operations. Cross contamination of clean glassware routinely occurs when plastics are handled during extraction steps, especially when solvent-wetted surfaces are handled. Interferences from phthalates can best be minimized by avoiding the use of plastics in the laboratory. Matrix interferences may be caused by contaminants that are co-extracted from the sample. The extent of matrix interferences will


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vary considerably from source to source, depending upon the nature and diversity of the site being sampled. Impurities in hexane create the greatest analytical problem. Because of the sensitivity of the ECD, distillation and other cleanup techniques rarely work to remove the interference peaks. Locate a solvent source that gives few impurities in the elution time range of the analytes. Currently Fisher brand HPLC grade hexane has been determined to be the best candidate. Use a sealed solvent dispenser to avoid further contamination. Adjust the GC temperature program accordingly if interferences are detected to attempt to separate analyte peaks from the impurity peaks. Fumigants can diffuse in and out of Teflon sealed vials. Therefore do not store samples and sample extracts with fumigant standards or any other samples containing high concentrations of fumigants. Current column technology suffers from the fact that EDB at low concentration may be masked by very high levels of dibromochloromethane (DBCM), a common disinfection by-product of chlorinated drinking water. In case of observed interferences with the parameters of interest, there are several options the analyst can use to remove or alleviate the problem:

1. Use another column type, length or diameter (if available) 2. Use another detector type (GC/MS) 3. Dilute In case the interference cannot be removed increase the MDL to the level of the lowest value obtained in two channels.

4. DEFINITIONS

4.1. ACCURACY: The closeness of agreement between an observed value and an accepted reference value. When applied to a set of observed values, accuracy will be a combination of a random component and of a common systematic error (or bias) component.

4.2. 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.

4.3. BIAS: The deviation due to matrix effects of the measured value (Xs - Xu) from a known

spiked amount. Bias can be assessed by comparing a measured value to an accepted reference value in a sample of known concentration or by determining the recovery of a known amount of contaminant spiked into a sample (matrix spike). Thus, the bias (B) due to matrix effects based on a matrix spike is calculated as: B = (Xs - Xu) - K where: Xs = measured value for spiked sample, Xu = measured value for unspiked sample, and K = known value of the spike in the sample. Using the following equation yields the percent recovery (%R). %R = 100 (Xs- Xu)/ K

4.4. PRACTICAL QUANTITATION LIMIT (PQL): The lowest concentration that can be reliably achieved within specified limits of precision and accuracy during routine laboratory operating conditions. The PQL is generally 5 to 10 times the MDL. However, it may be nominally chosen within these guidelines to simplify data reporting. For many analytes the PQL concentration is selected as the lowest non-zero standard in the calibration curve. Sample PQLs are highly matrix-dependent.

4.5. FIELD DUPLICATES: Independent samples which are collected as close as possible to

the same point in space and time. They are two separate samples taken from the same


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source, stored in separate containers, and analyzed independently. These duplicates are useful in documenting the precision of the sampling process.

4.6. LABORATORY FORTIFIED BLANK/LABORATORY CONTROL SAMPLE

(LFB/LCS): A known matrix spiked with compound(s) representative of the target analytes. The LFB is analyzed exactly as a sample. This is used to determine whether the methodology is in control, and whether the laboratory is capable of making accurate and precise measurements.

4.7. MATRIX: The component or substrate (e.g., surface water, drinking water) which

contains the analyte of interest.

4.8. MATRIX SPIKE: An aliquot of sample spiked with a known concentration of target analyte(s). The spiking occurs prior to sample preparation and analysis. A matrix spike is used to document the bias of a method in a given sample matrix.

4.9. MATRIX SPIKE DUPLICATES: A second aliquot of the same sample used for matrix

spike spiked with identical concentrations of target analyte(s). The spiking occurs prior to sample preparation and analysis. They are used to document the precision and bias of a method in a given sample matrix.

4.10. METHOD BLANK: An analyte-free matrix to which all reagents are added in the same

volumes or proportions as used in sample processing. The method blank should be carried through the complete sample preparation and analytical procedure. The method blank is used to document contamination resulting from the analytical process. For a method blank to be acceptable for use with the accompanying samples, the concentration in the blank of any analyte of concern should not be higher than the method detection limit

4.11. METHOD DETECTION LIMIT (MDL): The minimum concentration of a substance that can be measured and reported with 99% confidence that the analyte concentration is greater than zero and is determined from analysis of a sample in a given matrix type containing the analyte. For operational purposes, when it is necessary to determine the MDL in the matrix, the MDL should be determined by multiplying the appropriate one-sided 99% t-statistic by the standard deviation obtained from a minimum of seven analyses of a matrix spike containing the analyte of interest at a concentration one to five times the estimated MDL.

4.12. ORGANIC-FREE REAGENT WATER: All references to water in the method refer to

water in which interference is not observed at the method detection limit of the compounds of interest. Organic-free reagent water can be generated by passing tap water through a carbon filter bed containing about 1 pound of activated carbon. A water purification system may be used to generate organic-free deionized water.

4.13. PRECISION: The agreement among a set of replicate measurements without assumption

of knowledge of the true value. Precision is estimated by means of duplicate analyses. These samples should contain concentrations of analyte above the MDL, and involve the use of matrix spikes or laboratory fortified blanks. The estimates of precision are based on the relative percent difference (RPD). RPD = 100 [2 ( X1 - X2 ) / ( X1 + X2 ) ] where X1 and X2 are the two measurements


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4.14. QUALITY CONTROL CHECK STANDARD (QCS): A standard solution from a source, other than normal calibration standards, that is certified and traceable. These standards are used to check the accuracy of a calibration curve.

4.15. SPIKE SOLUTION (SS): A solution of method analytes of known concentrations that is

used to fortify an aliquot of laboratory reagent water or sample matrix.

4.16. STANDARD CURVE: A plot of concentrations of known analyte standards versus the instrument response to the analyte. Calibration standards are prepared by successively diluting a standard solution to produce working standards which cover the working range of the instrument. Standards should be prepared at the frequency specified in section six (6) of this SOP. The calibration standards should be prepared using the same type of solvent as the final sample preparation solvent.

5. APPARATUS AND EQUIPMENT

5.1. Gas Chromatograph: Agilent 6890 or 7890 capable of four steps temperature programming, with dual electron capture detectors, dual capillary split/splitless injectors and a dual HP 7673 Automatic Sampler. The GC and GC Automatic Sampler operating parameters are illustrated in Table 5 and Table 6 of the Appendix.

5.1.1. The first analytical column is a DB-5, J & W fused silica capillary, 30 m x 0.32

mm x 0.25 um or similar column.

5.1.2. The second column is a DB-608, J & W fused silica capillary, 30 m x 0.32 mm x 0.52 um or similar column.

5.1.3. Both columns can be used as primary or confirmatory based on the performance.

5.1.4. The column with the best performance, is chosen by the analyst to be

primary. The primary column is used to report the results. Important criteria for choosing the primary column: 5.1.4.1. Stable retention time windows during the entire run sequence 5.1.4.2. The best chromatography (no tailing or fronting, no impurity

interference with surrogates of target components) 5.1.4.3. The best calibration curves especially for target positives 5.1.4.4. The best LCS/Matrix Spikes results 5.1.4.5. The smallest number of CCV failures 5.1.4.6. The best surrogates results 5.1.4.7. The lowest %decomposition for Endrin/DDT

5.2. Data system

5.2.1. A computer system is interfaced to the Chromatograph that allows the

continuous acquisition and storage on machine-readable media of all chromatographic measurements obtained throughout the duration of the chromatographic run sequence program.

5.2.2. This system currently uses EZChrom Elite Client/Server from Agilent

Technologies, Inc. to acquire chromatographic data and Target software from ThermoFisher Scientific, Inc. to process and report the analysis results.

5.2.3. For reporting data, the system currently uses: DEP LIMS.


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5.3. Gases

5.3.1. Helium, UPC Grade, is used as the carrier gas. The helium is passed through an

oxygen and a hydrocarbon filter before it enters the GC.

5.3.2. Nitrogen, UPC Grade, is used as the make up gas for the ECD detectors. The N2 is passed through an oxygen and a hydrocarbon filter before entering the GC.

5.4. Glassware

5.4.1. Sample Containers: 43.0 +/- 0.5 mL screw cap amber vials. (i.e, referred to as

40 mL vials). Each vial is equipped with a PTFE faced silicone septum. Dirty vials may be soaked in acetone to remove the old label. Wash vials with hot soapy water and allow to dry in an oven (120 oC).

5.4.2. Autosampler Vials - Crimp top vials, suitable for the GC system being used.

5.4.3. Micro Syringes - 10 uL, 25 uL, 50 uL, and 250 uL.

5.4.4. Volumetric Flasks - 10 mL, 25 mL, and 50 mL.

5.4.5. Graduated Cylinder 10 mL, 50 mL.

5.4.6. Extraction Syringes - 5 mL, 2.5 mL glass, gas-tight syringes.

6. REAGENTS AND CHEMICALS

6.1. Reagents

n-Hexane - Fisher HPLC grade Methanol - Pesticide grade. Acetone - Pesticide grade. Sodium Chloride, NaCl ACS reagent grade, for pretreatment before use, pulverize

a batch of NaCl and place in a muffle furnace at room temperature. Increase the temperature to 400 0C for 30 minutes. Place in a battle and cap.

Sodium thiosulfate, Na2S2O3 ACS reagent grade. For preparation of solution (40 mg/mL), dissolve 1g of Na2S2O3 in reagent water and bring to 25 mL volume in a volumetric flask.

6.2. Neat Standards

1,2-Dibromoethane (EDB) - Neat standard (99+% purity). 1,2-Dibromo-3-chloropropane (DBCP) - Neat standard (99+% purity). Protect from

light.

6.3. Stock Standards Solution may be prepared in the DEP lab from neat standards or purchased from a certified manufacturer (ISO 9000 or EPA certified).

1,2-Dibromoethane (EDB) - 2000 ug/mL Solution from Chem Service or

AccuStandard 1,2-Dibromo-3-chloropropane (DBCP) - 2000 ug/mL Solution from Chem Service

or AccuStandard.


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6.4. Deionized (D.I.) Water: Water determined by method analysis to be free of fumigants

and interference peaks.

6.5. Stock and Intermediate Standards

6.5.1. Stock standards mixtures are concentrated standards prepared from neat standards (approximately 100% purity) once a year. Standards may be prepared in the DEP lab or purchased from a certified manufacturer (ISO 9000 or EPA certified).

6.5.2. Stock Solution (2 mg/mL)

6.5.2.1. This is 50.0 mg of EDB, and DBCP, in 25.0 mL of methanol. The

approximate volumes for these standards are 23.0 uL EDB, 23.9 uL DBCP.

6.5.2.2. This solution is prepared by weighing a 25.0 mL volumetric flask

partially filled with methanol. A microsyringe is used to deliver the standard below the neck of the flask and into the methanol. The new weight of the flask is recorded. The flask is filled to 25.0 mL after both fumigants have been added.

6.5.3. Intermediate (spike) solutions 1-6: Intermediate (spike) standard solutions are

mixture or individual standards used to prepare working standards. They are prepared in our lab from stock standards by mixing / diluting with methanol or can be purchased from a certified manufacturer (ISO 9000 or EPA certified). The concentrations of the components in the intermediate standards are listed in Table 2. Standards are replaced once per year. New standards are checked vs. standards in house and vs. a second source (QC Standards), after diluting them to one of the working standard level. The criterion of acceptance is +/- 10% difference. All standard preparations and verifications have to be recorded in the Standard Preparation Tracker located in DEP LIMS. A list containing all standards with their serial numbers used in the analysis must be part of analysis documentation folder. These solutions are used for the preparation of working standards as well as matrix spikes and lab fortified blanks. Levels 2, 4, and 6 are routinely prepared.

6.5.3.1. Spike solution 2: This is 25.0 uL of stock solution diluted to 25 mL

with methanol in a 25 mL volumetric flask.

6.5.3.2. Spike solution 4: This is 5 mL of stock solution 2 diluted to 25.0 mL solution with methanol in 25.0 mL volumetric flask.

6.5.3.3. Spike solution 6: This is 2.50 mL of stock solution 4 diluted to a 25.0

mL solution with methanol in a 25.0 mL volumetric flask.

6.5.3.4. Solutions may be mixed slowly using a Pasteur pipet. According to the EPA methods for volatile organics the volumetric flask may be inverted 2-3 times to mix without compromising sample integrity.

6.5.4. All solutions are stored in a refrigerator and allowed to warm to room

temperature before being used. 6.5.5. See Table 7 for routine standard preparation


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6.6. Working Standard Solutions (Calibration standards)

6.6.1. Working standard solutions are a series of diluted standards in hexane. They are used for calibration and are prepared by spiking intermediate (spike) standard solutions into vials containing 35 mL of water and are extracted with 2 mL of hexane. These standards are freshly prepared with each new extraction batch. A selected level (usually level 4) of second source (QCS) standard is also prepared and checked against the corresponding primary source standard. The acceptance criterion is +/-15% difference. The concentrations for each analyte in 35 mL water are presented in Table 3.

6.7. Quality Control Check Standards (QCS) are prepared from a source, other than

calibration standards, that is certified and traceable. These standards are used to check the integrity of the calibration standards.

7. SAMPLE COLLECTION, PREPARATION AND STORAGE

7.1. Samples must be collected in 40 mL glass containers. 7.2. All samples must be iced or refrigerated at 4 degrees C from time of collection until

extraction.

7.3. All samples must be analyzed within 28 days of collection. 7.4. In case the samples were chlorinated, add to each empty 40 mL container 3 mg of sodium

thiosulfate crystals as dechlorination agent. Alternately, 75 uL of freshly prepared sodium thiosulfate solution (40 mg/mL) may be added to empty 40 mL bottles just prior to sample collection.

8. SAMPLE PREPARATION PROCEDURE

8.1. Allow samples to warm to room temperature prior to extraction. 8.2. Remove the container cap. Discard 8 mL, using a disposable pipette in a 10 mL

graduated cylinder. Replace the container cap and weigh the container with contents to the nearest 0.1 g and record the weight for subsequent sample volume determination.

8.3. Remove the container cap and add 6 g NaCl to the sample. Recap the sample container

and dissolve the NaCl by shaking for about 20 seconds.

8.4. Prepare a D.I. water blank, calibration standards, check standards ( QCS, CCV, MDL check) in 43 mL vials: add 35 mL DI water, measured using 50 mL graduated cylinder, add 6 g NaCl and dissolve; add 20 uL of intermediate (spike) solution L4 QCS for the spikes and QCS check standard; 20 uL L4 for CCVs, and 20 uL of L6 for MDL check.

8.5. Remove the container cap and add 2 mL hexane into each container using 5 mL syringe.

Recap and shake for about 80 seconds.


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8.6. Set the container down and allow hexane and water layers to separate completely (If there is an emulsion, place vial in an ultrasonic water bath for several minutes to break up the emulsion).

8.7. Remove the cap and carefully transfer the hexane extract using a disposable pipette. Fill

up the autosampler vial. Keep the rest hexane extract into another vial. Crimp the autosampler vials. The sample is now ready for GC/ECD analysis.

8.8. Apply the same procedure to all samples, spikes, blanks and standards.

8.9. Determine the Sample Volume

8.9.1. Discard the remaining sample/hexane mixture. Shake off the remaining few

drops using short, brisk wrist movements. 8.9.2. Reweigh the empty container with original cap and calculate the net weight of

sample by difference to the nearest 0.1 g. This net weight (grams) is equivalent to the volume of water (in mL) extracted.

9. GENERAL DESCRIPTION OF GC/ECD ANALYSIS

9.1. Pre-Run GC Maintenance

9.1.1. Before starting an analysis run sequence, an initial checking and maintenance of the instrument has to be performed.

9.2. Summary of GC/ECD Analysis

9.2.1. The analysis of samples is accomplished by using two dissimilar fused silica

capillary columns, usually a DB-5 and a DB-608 or similar column (usually 0.32mm ID/30m/0.25-0.50 um).

9.2.2. Analysis is accomplished in two steps: identification of positives and

quantification of the positives.

9.2.3. Identification of positives requires all of the following QA/QC criteria to be meet:

9.2.3.1. Use of an updated multipoint calibration (updated Retention Times and

Response Factors).

9.2.3.2. Stable retention time windows (all calibration check standards are within the calibration windows).

9.2.3.3. Recoveries for LFB(s) and matrix spikes are within the control limits.

9.2.3.4. Continuing calibration check standard responses in both columns are

not to be below 15% of initial calibration.

9.2.4. All the samples are analyzed in two columns for confirmation of the target analyte hits. The LFB(s) and Matrix Spikes results, target analyte reported hits, are all based on one (the primary) column results. If for some analytes, QC criteria in the primary column are out of control limits, due to matrix


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interference or other problems, the result will be reported from the confirmatory column if QC criteria are met.

9.2.5. A target component is identified as positive if its peak is detected within its

appropriate retention time window in both columns. The amount of the prospective hit found in one column has to be confirmed in the other column. Criterion for the amount confirmation is equal to or less than +/- 30% difference between the two columns responses. If besides retention time, there is other evidence that the target analyte is a positive, and the amount in two columns does not match, the result will be reported based on the smallest value found in the two columns, and will be qualified as estimated (J).

9.2.6. Quantitative analysis of Fumigants is accomplished by the external calibration

method. All target component positives found have to be quantified using at least a three point calibration curve. The linearity of the calibration curve is defined by an RSD of =/


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9.3.3. The system is considered to be in initial linear calibration if the Relative Standard Deviation (%RSD) or the analyte calibration factors (using peak area calculation) is less than or equal to 20% (through origin) or the correlation coefficient is not lower than 0.995 if the calibration curve is not through origin. Use another curve fit if more appropriate

9.4. Continuing Calibration

9.4.1. After initial calibration, the GC/ECD response is checked on a continuing basis

(every 7-10 samples) by using continuing calibration check standards, usually L4. Criterion of acceptance for continuing calibration check is +/- 15% of initial calibration. If a continuing calibration check standard fails high (exceeds 15%) in both channels, all the samples bracketed by this standard have to be re-run for all hits more concentrated than PQL level. If the samples have exceeded the analysis holding time then all hits must be flagged as estimated.

9.4.2. When acceptance criteria for the continuing calibration verification are exceeded

low, i.e., low bias, those sample results (including non-detects) may be reported if they exceed a maximum regulatory limit/decision level. Otherwise the samples affected by the unacceptable verification shall be reanalyzed after a new calibration curve has been established, evaluated and accepted. If the samples have exceeded the analysis holding time then all detects and non-detects results must be flagged as estimated.

9.4.3. In order to quantify positives in the re-run samples, the calibration curve has to

be re-made by re-running calibration set together with the samples to be quantified. The GC-ECD system is also subjected to any maintenance that is deemed necessary to correct the calibration problem.

9.5. Analysis Run Sequence.

9.5.1. The analyst will set up an analysis run sequence by placing the GC vials

containing the sample extracts and standards on the autosampler tray in the following order or similar:

n-hexane blank (equipment blank) FUM-L2 FUM-L4 FUM-L6 FUM-QCS laboratory fortified blank ( LFB/LCS ) sample matrix spike (MS) sample matrix spike duplicate (MSD) extraction blank samples # 1 to # 9 FUM-L4 FUM-L6 samples #10 to # 19 FUM-L4 FUM-L6

9.6. Data Processing/Reporting


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9.6.1. Analytes are identified by matching retention times with those in the standard chromatograms. Typical retention times are listed in Table 4. Retention times will vary depending on the length of the column, but the elution sequence will be the same.

9.6.2. The concentration found in the sample extract (Cx) for an identified positive hit,

expressed in concentration in the 35 mL of theoretically extracted sample volume in ug/L, and corrected for real extracted volume of sample, is quantitated on the initial calibration curve. However, the analyst must ensure that all identification criteria are fulfilled and the peak area integration was correctly done. If not, the integration has to be re-done by choosing a new set of integration parameters or by manual integration. Target software will complete the calculation to determine the concentration of the analyte in the water sample (Csample) for the measured extracted volume Vsample . This is done using the formula:

Csample(ug/L) = (Cx) DF 35/ Vsample

Where : Cx - The concentration determined in the sample extract (ug/L) DF - The appropriate dilution recorded in the dilution report Vsample - Determined sample volume taken in extraction (usually close to

35 mLs)

9.7. Reporting results in DEP LIMS.

9.7.1. QA/QC results, MDLs, and positives are reported in the DEP LIMS using the QC Manager Program, instrument GC Pesticides: Target.

10. QUALITY CONTROL

10.1. For QA/QC see the Lab SOP GC-001-2.

10.2. QC criteria pertaining to this SOP are summarized in Table 6.

10.3. All data generated by a chemistry analyst are subjected to supervisory review and authorization. The supervisor is assessing the validity of data generated by assuring that all QA/QC criteria are met by checking the following review/authorization checklist: Check sample preparation report

Procedure Spiking solutions Preparation holding time Check project log-in folder for special requests

Check initial calibration for linearity Check continuing calibration check standards Check the QCS (Second source) report Check accuracy and precision for LFB and Matrix Spikes Check retention time drift Check for Blanks contamination Check for positives:

Proper integration of the peaks (baseline)


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Retention time confirmation Amount confirmation If response is within the calibration range Calculations Qualifiers

Check information in the Target Report Header: SOP # Instrument ID Column ID

Evaluate the data against any field information Check LIMS report:

Preparation and analysis dates MDLs. Amounts reported for positives Qualifiers Comments

11. METHOD PERFORMANCE

1.1. The MDLs are determined by using EPA recommended procedure (40 CFR Pt 136 Appx. B) Ref. 16.3 by analyzing at least 7 spikes in DEP D.I. water close to MDL levels. The spikes are run and analyzed in DB-5 and DB- 608. The Reported MDLs are chosen based on the highest value measured in any of the two columns. The equation used to calculate the MDL is as follows:

MDL = S t(n-1, 1-a=0.99)

Where: t(n-1, 1-a=0.99) is Student coeficient value for the 99% confidence level with n=number of replicates S=standard deviation

1.2. Run and analyze in the end of each analysis run sequence a L6 standard for MDL verification.

If the check does not pass, samples and standards must be re-run. If samples expired qualify the MDL reported for the failing parameters as estimated (J).

12. DATA ARCHIVAL

12.1. All raw data are retained in electronic or hard copy format. All paper formats are maintained either in the laboratory office or in a State warehouse for at least ten years. Electronic chromatographic raw data are archived by analysis file ID on optical disk in the DEP backup system. They are archived on optical disk approximately 6 months after data collection.

13. SAFETY

13.1. 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. From this viewpoint, exposure to these chemicals must be reduced to the lowest possible level by whatever means available. The laboratory is responsible for maintaining a current awareness file of OSHA regulations regarding the safe handling of the


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chemicals specified in this method. A reference file of material data handling sheets should also be made available to all personnel involved in the chemical analysis. The following parameters covered by this method have been tentatively classified as known or suspected, human or mammalian carcinogens: EDB and DBCP. Primary standards of these toxic compounds should be prepared in a hood. A NIOSH/MESA approved toxic gas respirator should be worn when the analyst handles high concentrations of these toxic compounds.

13.2. Lab clothing

13.2.1. Lab coats and safety eyeglasses must be worn at all times when in any

laboratory.

13.2.2. Use gloves when handling samples, standards, or solvents, or when washing glassware.

13.3. Chemicals involved

13.3.1. Even though the toxicity or carcinogeneity of some of the reagents used in this

method have not been precisely defined, each of them should be treated as a potential health hazard. From this point of view exposure to these chemicals must be reduced to the lowest possible level by whatever means available.

13.3.2. A reference file of Material Safety Data Sheets for each reagents used, is kept in

the GC room for documentation. Refer to this folder for any materials you are handling. Update this folder upon receiving new chemicals or reagents.

13.3.3. Primary standards of these toxic compounds should be prepared in a hood (See

Hood Usage). A NIOSH/MESA approved toxic gas respirator should be worn when handling highly concentrated solutions of these compounds.

13.4. Waste disposal (see Lab Manual Laboratory Waste Management January 2007)

13.4.1. Neat standards should be sealed and labeled.

13.4.2. All stock standards, working standards, and un-used sample extracts must be

emptied into two separate waste containers for Pesticides and PCBs. The container must be labeled properly with hazard warning labels indicating the containers contents.

13.4.3. Chlorinated and non-chlorinated solvents must be stored separately and labeled

properly.

13.4.4. GC vials containing, standards, and sample extracts, must be stored in two separate waste containers for Pesticides and PCBs. These containers should be labeled properly as to there contents and stored in the hood.

13.5. Flammable solvents must be stored in a flammables cabinet.

13.6. Hood Usage

13.6.1. Handle all sample extraction solvent transfers, concentrations, sample preps, and

cleanups in the hood at all times.

13.6.2. At any time, no more than two people can work at each hood.


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13.6.3. Turn the hood on and wait for adequate airflow. If there is no flow, DO NOT

USE THE HOOD!

13.7. Glassware

13.7.1. Inspect every piece of glassware to be used. Do not use any that are chipped, cracked, etched, or scratched.

13.7.2. Dispose of all unwanted, broken glassware in the blue GLASS box. One

should discriminate between unwanted, broken glassware and that which is only slightly damaged and reasonably easily repairable.

14. POLLUTION PREVENTION

14.1. Method requires using only 2 mL hexane solvent per sample, so no pollution of the environment will occur. Very little solvent will escape the fume hood. This small amount of solvent poses no threat to the environment.

15. REFERENCES

15.1. EPA 504 1,2-Dibromoethane (EDB), 1,2Dibromo-3-chloro-propane (DBCP), and 1,2,3-Trichloropropane (123TCP) in water by microextraction and gas chromatography (1993).

15.2. DEP SOP GC-001-2, Quality Assurance/Quality Control in the GC Pesticides Laboratory

16. APPENDIX TABLE 1. MDL/PQL List for Fumigants

Compound MDL PQL Boiling Pt. (ug/L) (ug/L) C 1,2-Dibromoethane (EDB) 0.010 0.040 131 1,2-Dibromo-3-chloropropane (DBCP) 0.010 0.040 196

TABLE 2. Concentration Levels for Intermediate (spike) Standards

Level

Concentration of intermediate spiking solution (ug/mL)

EDB DBCP 2 2 2 4 0.4 0.4 6 0.04 0.04


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TABLE 3. Concentration Levels for Fumigants in 35 mL water sample for 20 uL of spiking solution

Level Concentration of working standards (ug/L) EDB DBCP 2 1.15 1.15 4 0.23 0.23 6 0.023 0.023

TABLE 4. GC Operating Parameters for GC/ECD Analysis

GC Parameter Setting GC Parameter Setting GC Mode Const pressure Temperature 1 35 0C Injector Temperature 90 0C Time 1 1 minute Detector Temperature 325 0C Ramp 1 2 0C /minute Carrier Gas Helium Temperature 2 56 0C Column Head Pressure 18/14 psi Time 2 0 minute Total Flow Rate 36 mL per

minute Ramp 2 12 0C/minute Septum Purge Flow

Rate 4 mL per minute

Temperature 3 128 0C Make up Gas Nitrogen Time 3 2 minutes Make up Gas Flow

Rate 55 mL per minute

Ramp 3 30 0C/minute Injection Mode Splitless for 1 minute

Temperature 4 220 0C Injection Volume 2.0 uL Time 4 8 minutes R T Window 0.08/0.1 minute

(NOTE: The operating parameters for both columns are the same). TABLE 5. GC Operating Parameters for GC/ECD Analysis

Autosampler Parameter Setting Autosampler Parameter Setting Inj/Bottle 1 Volume (5 uL Syringe) 4 First Bottle 1 # of Solvent A washes 4 (Acetone) Last Bottle 99 # of solvent B washes 4 (Iso-Octane) # of Sample washes 2 Priority Sample (1=Yes) No # of Pumps 6 Capillary On-Column (1=Yes) No Viscosity 1


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TABLE 6. QC Measurements, Acceptance Criteria and Corrective Actions

# QC MEASUREMENT ACCEPTANCE CRITERION CORRECTIVE ACTION

1 LFB recoveries 60-140 % Reanalyze/Re-extract/Flag

2 Matrix Spike - recoveries - precision

60-140% =/< 30% Reanalyze/Re-extract/Flag

3 CCV +/- 15%(w) Re-run and recalibrate/Flag 4 QCS verification +/- 15% Re-run and recalibrate/Flag 6 MDL Instrument performance 80% -120% Maintain and re-run

7 Linearity criterion 20% RSD or 0.995 CC Use appropriate cal fit / Re-run/ Recalibrate

TABLE 7. Standard Preparation

# Standard Name Parent Standard

Name

Conc

Add

Final Standard vol (ml)

conc

Final Solvent

1 STOCK STD FUM STK. EDB QCS NEAT 99% 23.0 uL 25 2000 ppm methanol DBCP NEAT 99% 23.9 uL 25 2000 ppm methanol

2 FUM L2 EDB FUM STK. A 2000 ppm 25 uL 25 2.0 ppm methanol DBCP FUM STK. A 2000 ppm 25 uL 2.0 ppm methanol

3 FUM L4 EDB FUM L2 2.0 ppm 5 mL 25 0.4 ppm methanol DBCP 2.0 ppm 0.4 ppm methanol

4 FUM L6 EDB FUM L4 0.4 ppm 2.5mL 25 .04 ppm methanol DBCP 0.4 ppm .04 ppm methanol

5 FUM QCS STK. QCS EDB QCS NEAT 99% 23.0 uL 25 2000 ppm methanol DBCP NEAT 99% 23.9 uL 25 2000 ppm methanol

6 FUM L2 QCS EDB FUM STK.A QCS 2000 ppm 25 uL 25 2.0 ppm methanol DBCP 2000 ppm 25 uL 2.0 ppm methanol

7 FUM L4 QCS EDB FUM L2 QCS 2.0 ppm 5 mL 25 0.4 ppm methanol DBCP 2.0 ppm 0.4 ppm methanol

Documents

Analysis of Selected Fumigants in Water by Microextraction and GC-ECD