National Institute for Occupational Safety and Health

“ Desorption in toluene was adequate except as noted in 2 and 3 above. The use of toluene containing 10% acetone improved recoveries for all analytes to satisfactory levels. 5. The desorption characteristics of these compounds were not evaluated. General: a. The presence of acidic hydrogen or double bonded oxygen anywhere in the molecular structure greatly decreases solubility in non-polar solvents and increases the difficulty of desorption from polar surfaces and sorbents. ”

“ For liquid calibration standard preparations, add specified volume to 2 mL desorption solution in 2-mL volumetric flask. For laboratory control samples spiked at the REL, apply volume specified in column D to front section of sampler; in duplicate. For Desorption Efficiency determination, apply specified volume to front section of sampler; do each of five levels in triplicate. Total μg per sample, for spiked media, or per 2 mL desorption solution for liquid calibration standards. Where x, μg/sample = REL, μg/L x 120 L/sample ”

“ Some OVS-2 tubes contain glass fiber filters, as specified in the OSHA methods (see Table 10) . These tubes, however, did not perform as well for the more polar analytes (amides, phosphoramides, and sulfoxides; see Table 9) . Low or erratic recoveries for Malathion may be encountered with glass fiber filters. Personal sampling pump, 0.2 to 1 L/min. with flexible connecting tubing, preferably silicon, polyethylene, or PTFE tubing. Vials, 4-mL with PTFE-lined cap; 2-mL GC autosampler vials with PTFE-lined crimp caps. ”

“ Acetone is highly pump with flexible tubing. The sampler flammable. Prepare all samples in a well ventilated should be placed vertically with the large hood. end down, in the worker’s breathing zone in such a manner that it does not impede work performance. [4, 12] 3. Sample at an accurately known flowrate between 0.2 and 1 L/min for a total sample size of 12 to 240 L. NIOSH Manual of Analytical Methods (NMAM) , Fourth Edition, 8/15/94 ORGANOPHOSPHORUS PESTICIDES: METHOD 5600, Issue 1, dated 15 August 1994 - Page 3 of 20 4. ”

“ DB-5, 5% phenyl, 95% methyl silicone; DB-1701, 14% cyanopropylphenyl, 86% methyl silicone; DB-210, 50% trifluoropropyl, 50% methyl silicone. Other phase types may also work well. Thinner films give faster separations at lower temperatures promoting analyte stability. Use 2-mm i.d. injection port lines for 0.5-μL injection and 4-mm i.d. injection port liners for 1-to-2-μL injections with 0.32-mm i.d. capillary columns. SPL = splitless mode, initial oven temperature 5-10 °C < BP of desorption solvent; DIR = direct mode, initial oven temperature 5-10 °C > BP of desorption solvent. ”

“ The front section is separated from the back section of 140 mg XAD-2 sorbent or equivalent with a short plug of polyurethane foam. The back section is held in place by a long plug of polyurethane foam. The tube is available commercially as the OVS-2 sampler. ”