A New Sampling Procedure for Toluenediisocyanate (TDI

The current sampling and analytical procedure recommended by NIOSH for TDI is NIOSH Method No. 141. This method requires sampling with a midget impinger con taining acid scrubber solution and subsequent colorimetric analysis. The analytical method is based on the well tested Marcali Method. Inconveniences in obtaining per sonal samples with impingers are well known (i.e. sample spillage, scrubber solution evaporation, etc.). It is because of these difficulties that a new personal sampling pro cedure for TDI was developed. In this method, sample collection is accomplished by passing a known volume of air through a silica gel tube which has been spiked with an acid solution. TDI is trapped in the tube as a salt of the amine derivative of TDI and subsequently analyzed by the procedure in NIOSH method No. 141. Validation data are presented indicating the limits and reliability of this new sampling method.