Page:NIOSH Manual of Analytical Methods - 9106.pdf/3

 METHAMPHETAMINE. . .on Wipes by Liquid-Liquid Extraction: METHOD 9106, Issue 1, dated 17 October 2011 - Page 3 of 31

SPECIAL PRECAUTIONS: The solvents are flammable and have adverse health effects. Phenethylamines target the nervous system at very low concentrations and are easily absorbed through the skin. Avoid breathing vapors. Avoid skin contact. Work should be performed in a hood with adequate ventilation. Analysts must wear proper eye and hand protection (e.g. latex gloves) to prevent absorption of even small amounts through the skin. Dissolving sodium hydroxide and concentrated hydrochloric or sulfuric acid in water is highly exothermic. Goggles must be worn. The derivatization reagents react violently with water. Caution must also be exercised in the collecting, handling, and analysis of samples. Clandestine drug labs may produce unknown and seriously toxic by-products. For example, in the manufacture of designer drugs (e.g., MPPP, a homolog of Alphaprodine), at least one very neurotoxic by-product, 1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine (MPTP), has been identified that specifically and irreversibly causes Parkinson’s disease [5, 6]. SAMPLING: See APPENDIX C for special instructions on sampling. 1.	Using a new pair of gloves, remove a gauze wipe from its protective package. Moisten the wipe with approximately 3 to 4 mL of methanol (or isopropanol). NOTE 1:	 Apply no more solvent than that needed to moisten approximately the central 80% of the area of the gauze wipe. Excess solvent may cause sample loss due to dripping from the wipe. NOTE 2:	 Do not use vinyl gloves due to the potential for leaching of phthalate plasticizers and contamination of the samples. 2.	Place the template over the area to be sampled (may tape in place along outside edge of template). Wipe the surface to be sampled with firm pressure, using vertical S-strokes. Fold the exposed side of the pad in and wipe the area with horizontal S-strokes. Fold the pad once more and wipe the area again with vertical S strokes. 3.	Fold the pad, exposed side in, and place in shipping container and seal with cap. NOTE:	 Keep samples refrigerated (<6 ºC). While methamphetamine and several related amines are stable on the recommended wipe media for at least 7 days at room temperature, refrigeration is recommended as soon as possible (see Table 5). 4.	Either clean the template before use for the next sample or use a new disposable template. 5.	Label each sample clearly with a unique sample identifier. 6.	Prepare a minimum of two field blanks with one field blank for every ten samples. NOTE:	 In addition, include at least 3 media blanks for the analytical laboratory to use for their purposes. The wipes used for the media blanks should be from the same lot as the field samples. SAMPLE PREPARATION: See APPENDIX D for special instructions on sample preparation. 7.	Desorption from media: a.	 Remove cap from shipping container. NOTE:	 Sample wipe should fit loosely in the container. If not, transfer sample to a larger container. b.	 Spike 60 μL of internal standard spiking solution onto each wipe sample. c.	 Add 30 mL desorption solution (0.1 M sulfuric acid). NOTE:	 If the samples were transferred to a larger container, rinse the original shipping container with the desorption solution, shake, and decant the rinsate into the larger container. d.	 Cap securely and mix contents by inverting the tubes end over end on a rotary mixer or equivalent at 10-30 rpm for at least one hour. NIOSH Manual of Analytical Methods (NMAM), Fifth Edition

Method rev. 1.1.1