The physical and chemical analysis branch of the National Institute of Occupational Safety and Health reports an analytical method for organic solvents in air. The principle of the method is that a known volume of air is drawn through a charcoal tube to trap the organic vapors present. The charcoal in the tube is transferred to a small graduated test tube and desorbed with carbon disulfide. An aliquot of the desorbed sample is injected into a gas chromatograph, and the area of the resulting peak is determined and compared with areas obtained from the injection of standards. The following aspects of the method are discussed: range and sensitivity; interferences; precision and accuracy, advantages and disadvantages of the method; apparatus; reagents; procedure (cleaning equipment, calibration of personal pumps, collection and shipping of samples, analysis of samples, determination of desorption efficiency); calibration and standards; and calculations. Tested chemicals include: acetone, benzene, carbon tetrachloride, chloroform, dichloromethane, p-dioxane, ethylene dichloride, methylethyl ketone, styrene, tetrachloroethylene, 1,1,2-trichloroethane, 1,1,1- trichloroethane, trichloroethylene, toluene, xylene.
Physical and Chemical Analysis Branch, National Institute for Occupational Safety and Health, 11 pages, 4 references