Page:NIOSH Manual of Analytical Methods - 9106.pdf/2

 METHAMPHETAMINE. . .on Wipes by Liquid-Liquid Extraction: METHOD 9106, Issue 1, dated 17 October 2011 - Page 2 of 31

REAGENTS: NOTE: See APPENDIX A for special instructions on reagents. 1.	 Analytes listed in Table 1.* 2.	 Internal standards from those listed in Table 9. 3.	 Solvents, residue free analytical grades: a.	 Hexane * b.	 Isopropanol (IPA)* c.	 Methanol * d.	 Methylene chloride (CH2Cl2) * e.	 Toluene * f.	 Acetone* 4.	 Concentrated sulfuric and hydrochloric acids (AR or trace metals analysis grades).* 5.	 Sodium hydroxide, A.C.S. grade.* 6.	 Anhydrous granular sodium sulfate, AR grade. 7.	 Anhydrous granular potassium carbonate, AR grade. 8.	 Bromothymol Blue, ≥95%, A.C.S., phenolphthalein, A.C.S.; crystal violet (Gentian Violet), ≥95%, A.C.S. 9.	 Purified gases: helium for carrier gas, nitrogen for drying. 10.	 Chlorodifluoroacetic anhydride, 98%* derivatizing agent. Moisture sensitive! 11.	 4,4’-Dibromooctafluorobiphenyl, 99%, instrument internal standard (IIS). 12.	 Deionized water (ASTM type II).

SOLUTIONS: NOTE: See APPENDIX A for special instructions on solutions. 1.	 Prepare solutions of analytes of interest. Calculate concentrations as the free base. Keep refrigerated (<6 °C). Protect solutions from light. a.	 Stock solutions are prepared at about 1-2 mg/mL in methanol. b.	 Analyte spiking solutions are prepared by diluting the stock solutions to about 200 μg/mL each in methanol. 2.	 Prepare internal standard spiking solution in methanol at about 200 μg/mL. (Note: Add about 2 milligrams of crystal violet per 20 mL of internal standard spiking solution to help indicate which samples have been spiked.) 3.	 Desorption solution: 0.1 M H2SO4 (sulfuric acid.) Add 22 mL conc. sulfuric acid to 4 L deionized water. 4.	 Bromothymol blue and phenolphthalein pH indicator solution: 1 mg/ mL each in 4:1 isopropanol: deionized water. 5.	 Sodium hydroxide*, 10 M: Dissolve 40 grams sodium hydroxide in enough deionized water to make 100 mL. Do not store in glassstoppered bottle. 6.	 Hydrochloric acid, 0.3 M, in methanol: Dilute 2.5 mL conc. hydrochloric acid in about 80 mL methanol; dilute to 100 mL with methanol. 7.	 Crystal violet indicator: 2-3 mg/mL in isopropanol. 8.	 Reconstitution solvent: 10% acetone in toluene with 4 μg/mL of 4,4’-dibromooctafluorobiphenyl (optional).*

EQUIPMENT: NOTE: See APPENDIX B for special instructions on equipment. 1.	 Wipe, (7.6 cm × 7.6 cm) 12-ply or equivalent. 2.	 Sample storage and shipping container: 50-mL polypropylene centrifuge tubes with PTFE-lined caps. 3.	 Extraction tubes and vials: a.	 Glass test tubes, 25-mL (20 × 120 mm), with PTFE-lined caps; b.	 Glass test tubes, 14-mL (16 × 100 mm), with PTFE- lined caps, (ASTM Specification E982, or equivalent, suitable for repeated autoclaving); c.	 Amber GC autosampler vials (2-mL) and caps. 4.	 Gas chromatograph/mass spectrometer detector, with column and integrator, see p. 9106-1. 5.	 Liquid Transfer: a.	 Syringes: 10-, 25-, 100-, and 500-μL sizes. b.	 Mechanical pipette with disposable tips or repeating dispenser: 0.5-, 2.5-, and 10-mL sizes. c.	 Repeating dispenser: 1- to 5-mL. d.	 Three repeating dispensers: 10 to 20-mL each. 6.	 Volumetric flasks: 10-, 100-, and 250-mL. 7.	 Forceps. 8.	 Gloves, latex or nitrile. Avoid vinyl gloves (see 9106-3, Sampling step 1, NOTE 2). 9.	 Scoop for solid reagents. 10.	 Empty drying columns: 1 cm i.d. × 12-15 cm length polypropylene plastic columns having a fritted polyethylene disc or equivalent (e.g. 10-mL pipette tip with small wad of silanized glass wool packed into the tip). 11.	 Nitrogen blow-down apparatus with water bath capable of maintaining 35 ºC. 12.	 Vortex mixer. 13.	 Rotating mixer capable of 10-30 rpm. 14.	 Aspirator flask: 1-L, with aspirator tubing and a 12.5 cm long 16 gauge needle. 15.	 Centrifuge: capable of up to 4000 x g and of holding 25-mL glass test tubes. 16.	 Oven capable of 70 to 90 ºC ± 2 ºC. 17.	 Test tube racks, heat resistant to 90 ºC. 18.	 Pasteur pipettes. 19.	 pH paper. 20.	 Template: 10 cm × 10 cm or 31.7 cm × 31.7 cm opening, made of relatively rigid disposable cardstock or sheet of PTFE. 21.	 Ice or other cold media for shipping.


 * See SPECIAL PRECAUTIONS

Method rev. 1.1.1

NIOSH Manual of Analytical Methods (NMAM), Fifth Edition