Determination of airborne 2,4-toluenediisocyanate vapors

An accurate and convenient sampling and analytical method was developed for airborne 2,4-toluenediisocyanate (TDI). A chromophoric derivatizing reagent was used to convert the TDI to a stable urea derivative during collection for subsequent quantification by liquid chromatography. The overall accuracy (at the 95% confidence level) and precision of the method are +/- 7.9% and +/- 10.0% respectively under laboratory conditions. Long term stability was observed for both the reagent coated sorbent tube and the TDI urea derivative. A TDI concentration of 1 ppb can be detected by taking a 15-1 sample volume.