Page:NIOSH Manual of Analytical Methods - 8324.pdf/2

 3-BROMOPROPIONIC ACID in URINE: METHOD 8324, Issue 1, dated 29 August 2014 - Page 2 of 9

REAGENTS:

EQUIPMENT:

1.	3-Bromopropionic acid (3-BPA) reference standard as a 1.0 mg/mL stock solution in deionized water. Store in a refrigerator. 2.	3-Chloropropionic acid (3-CPA) reference standard, 20 μg/mL in deionized water, internal standard solution. Store in a refrigerator. 3.	Ethyl acetate, HPLC grade or better* 4.	N-Methyl-N-(tert-butyldimethylsilyl) trifluoroacetamide (MTBSTFA) with 1% tertbutyldimethylchlorosilane (TBDMCS) 5.	Magnesium sulfate, anhydrous, powdered, ACS reagent grade 6.	Hydrochloric acid, concentrated, ACS reagent grade 7.	Water, deionized (ASTM type II) 8.	Nitrogen, prepurified grade or better 9.	Urine, non-exposed*
 * See SPECIAL PRECAUTIONS

1.	Gas chromatograph with mass spectrometric detector, column, autosampler, and data collector (page 8324-1) 2.	Bottles, polypropylene, 125-mL with caps 3.	Analytical balance, to ±0.0001 g 4.	Analytical evaporator with nitrogen gas sweep 5.	Test-tube vortex mixer 6.	Heating block or oven 7.	Automatic pipettor with disposable tips 8.	Repeating pipet dispenser, 1 L 9.	Tubes, disposable screw-top culture (16 X 100 mm and 16 X 150 mm), with polytetrafluoroethylene (PFTE)-lined caps 10.	Metal spatula 11.	Flasks, volumetric; 10, 50 and 100-mL 12.	Autosampler vials, 2 mL, silanized, with caps and septa 13.	Glass funnels 14.	Glass wool, silanized 15.	Disposable glass pipets 16.	Dry ice or bagged refrigerant

SPECIAL PRECAUTIONS: Standard precautions should always be used when handling bodily fluids and/or extracts of bodily fluids [10]. Handle urine samples and urine extracts using powder-free latex or nitrile gloves. Ethyl acetate and MTBSTFA are flammable; handle with care and use in a chemical fume hood. Handle all chemicals using the required safety precautions. Manufacturer expiration dates for reagents should be observed. SAMPLING: 1.	Collect at least 15 mL urine in an appropriate polypropylene tube or bottle and cap. Refrigerate or freeze immediately after collection. Collect at least two urine specimens for each worker: one before the work shift and one after. 2.	Ship the specimens stored in either wet or dry ice in an insulated container. Store frozen upon arrival at the laboratory. A reminder: commercial shippers have special labeling requirements for packages containing dry ice. SAMPLE PREPARATION: 3.	Thaw the urine specimen to room temperature. 4.	Mix thoroughly to ensure urine homogeneity. 5.	Transfer 2.0 mL of urine into a 16 X 100 mm (or larger) screw-capped culture tube. 6.	Acidify by adding 40 μL of concentrated hydrochloric acid. 7.	Add 0.5 mL of deionized water. 8.	Add 0.5 mL of the 20 μg/mL 3-CPA internal standard solution. 9.	Ethyl Acetate Extraction: Dispense 4 mL of ethyl acetate into the culture tube, cap, and vortex (or vigorously shake) for 1 minute. 10.	Allow layers to separate, collect the ethyl acetate (top) layer.

NIOSH Manual of Analytical Methods (NMAM), Fifth Edition