Oil & Grease – EPA Method 1664 Rev. B

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NC DEQ/DWR LABORATORY CERTIFICATION

LABORATORY NAME: / CERT #:
PRIMARY ANALYST: / DATE:
NAME OF PERSON COMPLETING CHECKLIST (PRINT):
SIGNATURE OF PERSON COMPLETING CHECKLIST:

Parameter: Oil & Grease

Method: EPA Method 1664 Rev. B (Aqueous)

Auditor’s Guide

Rev. 6/14/2017

Oil & Grease – EPA Method 1664 Rev. B

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EQUIPMENT:

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Oil & Grease – EPA Method 1664 Rev. B

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Glassware Cleaning
Laboratory sink with overhead fume hood
Oven–Capable of maintaining a temperature within ± 2 ºC in the range of 20–250 °C
Calibration
Analytical Balance–Capable of weighing 0.1 mg.
Volumetric flask–Glass, 100-mL.
Vials–Assorted sizes, with PTFE-lined screw caps.
Volumetric pipette–Glass, 10-mL.
Sample Extraction
Balance (optional)–Top loading, capable of weighing 500–2000 g within ± 1%
Glass stirring rod
Separatory funnel–Glass, 2000-mL, with PTFE stopcock
Funnel–Large, glass, for pouring sample into separatory funnel
Centrifuge (optional)–Explosion proof, capable of spinning at least four 100-mL glass centrifuge tubes at 2400 rpm minimum
Centrifuge tubes (optional)–100-mL glass
Wash bottle (optional)–Fluoropolymer construction for hexane rinses
Solid Reagent Removal
Funnel–Analytical, glass
Filter paper–Whatman No. 40 (or equivalent), to fit funnel
Distillation
Water bath or Steam bath–Explosion-proof, capable of maintaining a temperature of at least 85°C
Flask–Boiling, 125-mL (Corning No. 4100 or equivalent)
Distilling head–Claisen (VWR Scientific No. 26339-005, or equivalent), includes Claisen-type connecting tube and condenser
Distilling adaptor (attached to the distilling head and to the distillate collection flask for recovery of solvent)
Distillate collection flask (attached to the distilling adaptor for collection of the distilled solvent)
Ice bath or recirculating chiller (to aid in the condensation and collection of the distilled solvent)
Vacuum–Vacuum pump or other source of vacuum
Tongs, for handling the boiling flask (Humboldt Manufacturing No. H-23442, or equivalent)
Desiccator–Cabinet- or jar-type, capable of keeping the boiling flask (Section 6.6.2) dry during cooling
Hood-Explosion-proof, capable of accommodating the equipment used for solvent distillation (Section 6.6.1–6.6.5)
Adsorbable Reagent Removal
Magnetic stirrer
PTFE-coated magnetic stirring bars
Graduated cylinder–500-mL, capable of measuring ± 5 mL
Pipettes–Assorted sizes, calibrated to within ± 0.5 percent

Rev. 6/14/2017

Oil & Grease – EPA Method 1664 Rev. B

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REAGENTS & STANDARDS:

Rev. 6/14/2017

Oil & Grease – EPA Method 1664 Rev. B

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Reagent water–Water in which HEM is not detected at or above the minimum level (ML) of this method.
Hydrochloric acid or sulfuric acid–ACS. Mix equal volumes of concentrated HCl and reagent water or 1 part H2SO4 and 3 parts reagent water to produce an approximately 6N solution
n-Hexane–85% minimum purity, 99.0% min. saturated C6 isomers, residue less than 1 mg/L (0.0001% max.)
Acetone–ACS, residue less than 1 mg/L (0.0001% max)
Sodium sulfate–ACS, granular anhydrous. Dry at 200-250 °C for 24 h minimum and store in a tightly sealed container until use
Boiling chips–Silicon carbide or fluoropolymer
Silica gel–Anhydrous, 75-150 µm, 30 Å pore size (Davisil Grade 923, or equivalent).
Hexadecane–98% minimum purity
Stearic acid–98% minimum purity

Rev. 6/14/2017

Oil & Grease – EPA Method 1664 Rev. B

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Rev. 6/14/2017

Oil & Grease – EPA Method 1664 Rev. B

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PLEASE COMPLETE CHECKLIST IN INDELIBLE INK
Please mark Y, N or NA in the column labeled LAB to indicate the common lab practice and in the column labeled SOP to indicate whether it is addressed in the SOP.
GENERAL / LAB / SOP / EXPLANATION
1 / What is the most recent review/revision date of the SOP? [15A NCAC 2H .0805 (a) (7)] / Date:
Verify proper method reference. During review notate deviations from the approved method and SOP. Recommend an annual review. Update SOPs any time changes are made to procedure and make a list or highlight any changes that were made to methodology.
2 / Is there North Carolina data available for review? / If not, review PT data
SAMPLE COLLECTION, PRESERVATION and STORAGE / LAB / SOP / EXPLANATION
3 / Are samples collected in glass bottles? [40 CFR 136.3 Table II and footnote 1]
4 / Are samples iced to above freezing but ≤ 6 º C during shipment?
[40 CFR 136.3 Table II and footnote 18]
5 / Are samples preserved at time of collection with HNO3 to pH of <2 S.U.? [40 CFR 136.3 Table II and footnotes 2 and 3] / Preservation not required if analyzed within 15 minutes.
6 / If a sample is known or suspected of containing greater than 500 mg/L of extractable material or consists of a matrix containing substances that may interfere with the extraction procedure, then is a proportionally smaller volume of sample collected with a proportionally smaller amount of preservative? [EPA Method 1664, Rev. B, Section 8.1.2] / If a sample is known or suspected to contain greater than 500 mg/L of extractable material or consists of complex matrix containing substances (such as particulates or detergents) that may interfere with the extraction procedure, collect a proportionately smaller volume of sample (the volume required will depend upon the estimated amount of extractable material) in a glass bottle. Add a proportionately smaller amount of HCl or H2SO4 solution to the smaller sample for preservation as necessary.
7 / Is an additional aliquot collected for each set of twenty samples or less to be used for the matrix spike? [EPA Method 1664, Rev. B, Section 8.2] / Collect an additional one or two aliquots (1 L, additional smaller volume, or both) of a sample for each set of twenty samples or less for the matrix spike and, if used, the matrix spike duplicate.
8 / Are samples collected as grab samples? [EPA Method 1664, Rev. B, Section 8.3] / The high probability that extractable matter may adhere to sampling equipment and result in measurements that are biased low precludes the collection of composite samples for determination of oil and grease. Therefore, samples must be collected as grab samples.
9 / If a composite sample is required, then are individual grab samples collected at the prescribed time intervals and subsequently composited in the lab? [EPA Method 1664, Rev. B, Section 8.3] / If a composite measurement is required, individual grab samples collected at prescribed time intervals must be analyzed separately and the concentrations averaged. Alternatively, samples can be collected in the field and composited in the laboratory. For example, collect four individual 250 mL samples over the course of a day. In the laboratory, pour each 250-mL sample into the separatory funnel, rinse each of the four bottles (and caps) sequentially with 30 mL of n-hexane, and use the 30 mL of n-hexane for the extraction (Section 11.3).
10 / Are samples refrigerated to above freezing but <6°C during storage?
[40 CFR 136.3 Table II and footnote 18]
11 / Are samples analyzed within 28 days of collection?
[40 CFR 136.3 Table II]
Calibration - BALANCE / LAB / SOP / EXPLANATION
12 / Is the balance calibration verified with 2 mg and 1000 mg weights prior to weighing each batch of samples? [EPA Method 1664, Rev. B, Section 10.1] / Calibrate the analytical balance at 2 mg and 1000 mg, using class “S” or ASTM E 617-1997 Class 1 weights. It is recommended that the balance should also be calibrated with an additional class “S” or ASTM E 617-1997 Class 1 weight that will bracket the final expected weighing value.
13 / Is the analytical balance calibration verified with 2 mg and 1000 mg weights after weighing each analytical batch of samples? [EPA Method 1664, Rev. B, Section 9.5] / Verify calibration of the balance per Section 10 before and after each analytical batch. If calibration is not verified before and after each day or after measurement of the analytical batch, recalibrate the balance and reweigh the batch.
14 / If the verification is not within ± 10% at 2 mg and ± 0.5% at 1000 mg, then is the balance recalibrated? [EPA Method 1664, Rev. B, Section 10.2] / Calibration shall be within ± 10% (i.e. ± 0.2 mg) at 2 mg, ± 0.5% (i.e., ± 5 mg) at 1000 mg, and if applicable, at the appropriate user-specified tolerance for Class 1 weights greater than 1000 mg. If values are not within these limits, recalibrate the balance.
PROCEDURE – PREPARATION / LAB / SOP / EXPLANATION
15 / Are the samples and QC brought to room temperature? [EPA Method, 1664 Rev. B, Section 11.1.1] / Bring the analytical batch of samples, including the sample aliquots for the MS (and MSD), to room temperature.
16 / Is approximately 1000 mL of reagent water placed in clean sample bottle to serve as the laboratory blank? [EPA Method 1664, Rev. B, Section 11.1.2] / Place approximately 1000 mL (950–1050 mL) of reagent water (Section 7.1) in a clean sample bottle to serve as the laboratory blank.
17 / Is the OPR prepared using the PAR standard? [EPA Method 1664, Rev. B, Section 11.1.3] / Prepare the OPR (Section 9.6) using the PAR standard (Section 7.11).
18 / Are sample bottles marked at the water meniscus or are the sample bottles weighed for subsequent determinations of sample volumes? [EPA Method 1664, Rev. B, Section 11.1.4] / Either mark the sample bottle at the water meniscus or weigh the bottle for later determination of sample volume. Weighing will be more accurate. Mark or weigh the MS (and MSD).
19 / Are the QC samples (blank, OPR, MS and MSD) adjusted to a pH of < 2? [EPA Method 1664, Rev. B, Section 11.2.4] / Add the appropriate amount of HCl or H2SO4 solution to the blank, OPR, MS (and MSD) to adjust the pH of these solutions to <2.
20 / Is sample preservation to pH of <2 S.U. verified prior to sample analysis? [EPA Method 1664, Rev. B, Sections 11.2.1.1, 11.2.1.2, 11.2.1.3] / Preservation should not be checked in sample receiving. It should be checked at the bench, just prior to analysis. See comments in next question.
21 / Is the preservation to pH of <2 S.U. verified by dipping a glass stirring rod into the well mixed sample, allowing a drop of sample to touch pH paper, and rinsing the glass stirring rod with n-hexane into the separatory funnel? [EPA Method 1664, Rev. B, Sections 11.2.1.1, 11.2.1.2, 11.2.1.3] / NOTE: Do not dip the pH paper into the bottle or touch it to the sample on the lid.
11.2.1.1 Dip a glass stirring rod into the well mixed sample.
11.2.1.2 Withdraw the stirring rod and allow a drop of the sample to fall on or touch the pH paper.
11.2.1.3 Rinse the stirring rod with a small portion of n-hexane that will be used for extraction (to ensure that no extractable material is lost on the stirring rod). Collect the rinsate in the separatory funnel to be used for sample extraction.
22 / Describe the action taken to adjust sample pH when the pH of the sample is >2 S.U. [EPA Method 1664, Rev. B, Section 11.2.2] / If possible, collect and analyze another sample. If resampling is not possible, notify NC WW/GW LC of improper preservation, qualify results on the eDMR and/or client report and follow the following procedure:
If the sample is at neutral pH, add 5-6 mL of HCl or H2SO4 solution (Section 7.2) to the 1-L sample. If the sample is at high pH, use a proportionately larger amount of HCl or H2SO4 solution. If a smaller sample volume was collected, use a proportionately smaller amount of HCl or H2SO4 solution.
23 / If more acid is added to the sample to adjust pH, then is the pH re-verified after the sample is capped and thoroughly mixed? [EPA Method 1664, Rev. B, Section 11.2.3] / Replace the cap and shake the bottle to mix thoroughly. Check the pH of the sample using the procedure in Section 11.2.1. If necessary, add more acid to the sample and retest.
PROCEDURE – EXTRACTION / LAB / SOP / EXPLANATION
24 / Is one of the allowable alternative extraction procedures performed? If so, describe the extraction process. [EPA Method 1664, Rev. B, Section 1.7.1.1] / Alternate extraction techniques including continuous liquid-liquid extraction, solid-phase extraction, solid-phase-heated solvent extraction, solid-phase-Soxhlet extraction, and others. Acceptable solid-phase extraction (SPE) products include: Xenosep filters for EPA Method 1664, part no. 24547 and 25390H or equivalent; UCT LLC Oil and Grease cartridge part no. ECUNIOGXF, or equivalent; or other SPE products that meet all method performance criteria such as Horizon part no. 50-021-HT, Snip and Pour QC Standard or equivalent.
25 / Is the flask containing boiling chips dried in an oven at 105–115 °C for a minimum of 2 hours and cooled to room temperature? [EPA Method 1664, Rev. B, Sections 11.3.1.1, 11.3.1.2, 11.3.1.3] / 11.3.1.1 Place the flask containing the chips in an oven at 105–115 °C for a minimum of 2 h to dry the flask and chips.
11.3.1.2 Remove from the oven and immediately transfer to a desiccator to cool to room temperature.
26 / When cool, are the flasks containing boiling chips weighed? [EPA Method 1664, Rev. B, Section 11.3.1.3] / 11.3.1.3 When cool, remove from the desiccator with tongs and weigh immediately on a calibrated balance (Section 10).
27 / Is the sample added to the separatory funnel first? [EPA Method 1664, Rev. B, Section 11.3.2] / Pour the sample into the separatory funnel.
28 / Is 30 mL of n-hexane added to the sample bottle and sealed with the original bottle cap? [EPA Method 1664, Rev. B, Section 11.3.3] / Add 30 mL of n-hexane to the sample bottle and seal the bottle with the original bottle cap.