Determination of diisocyanate monomers in air by differential-pulse polarography

Abstract

A method for the determination of hexane-1,6-diyl diisocyanate, 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethylcyclohexane, toluene-2,4-diyl diisocyanate and toluene-2,6-diyl diisocyanate in air by differential-pulse polarography (DPP) is described. The monomers are derivatized with 4-nitro-N-propylbenzylamine (nitro reagent). The excess of nitro reagent is removed by using solid-phase extraction columns and the ureido derivatives are determined by DPP in 0.2 mol dm^–3 KOH [methanol–water (80 + 20)] as the total concentration of diisocyanate in the sample.