Gas-chromatographic determination of trace amounts of vinyl chloride in water and air after derivatization to 1,2-dibromochloroethane

A quantitative method for the determination of trace amounts of vinyl chloride in water and air is presented. Analysis of water is performed by stripping it with 250 ml/min helium from a 1-l sample at 20°C for 30 min to transfer the vinyl chloride into the gas phase. The vinyl chloride is concentrated on an ice-cooled adsorption tube, which is filled with 550 mg of silica gel and 300 mg of activated charcoal. Air samples are taken by drawing a known volume directly through the ice-cooled adsorption tube. The tubes are eluted with carbon disulfide and the vinyl chloride is derivatizised with bromine water to form 1,2-dibromochloroethane. The derivative is determined by capillary gas chromatography with an electron capture detector. The method was tested using water samples over a range from 0.4 ng/l to 1.25 μg/l. The detection limits are 0.4 ng/l for 1-l water samples or 50 ng/m3 for 7.5 l air.