Collection and Chemical Derivatization of Airborne Phosgene with 1-(2-Pyridyl)-Piperazine and Determination by High Performance Liquid Chromatography

Abstract

As an alternative to currently available measurement methods, Chromosorb coated with l-(2-pyridyl)-piperazine (PYP) was evaluated for collection / derivatization of phosgene gas. Solid sorbent tubes contained 100 mg of 2.5% PYP coated on Chromosorb. Phosgene reacts with two equivalents of PYP to form a substituted urea derivative which is desorbed with acetonitrile and determined by reversed phase high performance liquid chromatography with ultraviolet absorbance detection. In comparison to the 4,4′-nitrobenzyl pyridine in diethylphthalate colorimetric technique, the recovery of phosgene from the sorbent tube was quantitative from 0.02 to 1 ppm phosgene and was unaffected by humidity. The limit of detection for a 20 L air sample was estimated to be 0.005 ppm. The utility of the method was further improved by demonstrating the use of triphosgene [bis-(trichloromethyl)-carbonate] in the synthesis of the urea derivative used for standardization, thus eliminating the need for working with gaseous phosgene in preparing analytical standards.