A new simple method for monitoring permeation through clothing materials of dibutyl sulphide, a chemical warfare agent simulant

A new simple method is proposed for monitoring permeation of dibutyl sulphide through protective clothing materials. The method is based upon the reaction of sodium nitroprusside with sulphide ions in alkaline medium. It is carried out as a spot test on the filter paper previously impregnated with sodium nitroprusside as indicator compound or directly on clothing material. The violet colour that indicates the presence of sulphide ions is detectable with a magnifying glass and even with the naked eye. The method was applied for the determination of breakthrough times of some intermediates in the fabrication of protective clothing materials, based on polyester fibres technologically treated among other chemicals, with 4,4′-dithiomorpholine, 2-mercaptobenzothiazole disulphide and dipentamethylenethiuram tetrasulphide. The widely recommended fluorescence quenching technique was in this case shown to be inapplicable because of severe interferences caused by technological pretreatment of clothing materials, resulting in diminished fluorescence signals of indicator compounds by mere contact with clothing materials. The new analytical method is sensitive enough, shows no interferences and is a simple, fast, and low cost test for permeation monitoring of dibutyl sulphide.