Pentafluorobenzyl p-toluenesulphonate as a new derivatizing reagent for electron-capture gas chromatographic determination of trace inorganic anions

Abstract

Inorganic anions in water were reacted with pentafluorobenzyl p-toluenesulphonate in dichloromethane, using tetra- n-amylammonium chloride as a phase-transfer catalyst. Bromide, iodide, thiocynate and nitrate at relatively low concentrations can be pentafluorbenzylated, and the resulting derivatives can be detected by electron -capture gas chromatography. The interferences of some anions were examined. The recovery test of bromide, iodide or thiocynate spikes and an intercomparison study for nitrite were performed. This gas chromatographic method has been successfully applied to the determination of bromide and iodide in kelp extract, and thiocyanate and/or nitrate in human urine or saliva.