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
