Document gaj9Gba6RQpQNv8yapOrw6oRq

I # Page Ten Method for Determination of VDC in Air NOTE 1: NOTE 2: NOTE 3: For your information, 29 CFR 1910.1.17(f)(2) has been repro duced here: "Wherever feasible engineering and work practice controls which can be instituted immediately are not sufficient to reduce exposures to at or below the permissible exposure limit, they shall nonetheless be used to reduce exposures to the lowest practicable level, and shall be supplemented by respiratory protection in accordance with paragraph (g) of this section. A program shall be established and implemented to reduce exposures to at or below the permissible exposure limit, or to the greatest extent feasible, solely be means of engi neering and work practice controls, as soon as feasible." If difficulties arise from blowback or distillation within the syringe needle, one should employ the solvent flush in jection technique. The 10 pL syringe is first flushed with solvent several times to wet the barrel and plunger. Two microliters of solvent are drawn into the syringe to increase the accuracy and reproducibility of the injected sample volume. The needle is removed from the solvent and the plunger is pulled back about 0.4 pL to separate the solvent flush from the sample with a pocket of air to be used as a marker. The needle is then immersed in the sample, and a 2pL aliquot is withdrawn to the 4.4 pL mark (2pL solvent + 0.4 pL air + 2 pL sample = 4.4 pL) . After the needle is removed from the sample and prior to injection the plunger is pulled back a short distance to minimize evaporation of the sample from the tip of the needle. If high blank values are obtained from a specific lot of charcoal it is recommended that the charcoal be discarded rather than attempting to apply a correction. 51 sa38s