A sample-bottle purging method for the determination of vinyl chloride in water at submicrogram per liter levels.

Methodology is presented for the concentration, detection and measurement of vinyl chloride (VC) in water at a maximum sensitivity of 0.1 mug/1 by gas chromatography, using the halogen specific microcoulometric titration detector. The methodology eliminates cyanogen chloride (CNCI) as a potential interference by using a 180 mm X 4 mm i.d. GC column packed in the first one-third with Chromosorb 101, and in the second two-thirds with Chromosorb 102; a procedure for purging the sealed sample bottle itself is utilized as a means of analyzing larger samples, while at the same time avoiding the loss of VC by volatilization which occurred when the sample was transferred to a purging device. A method of verifying the accuracy of standard solutions that utilizes a new device called a "Reaction Coulometer," is also included and a detailed description of how to convert the inlet system of the Tracor MT 220 gas chromatograph to a desorbing device is provided.