Concepedia

Abstract

An easy-to-use analytical method for determining toluene diisocyanate (TDI) vapor in air has been developed utilizing electron capture gas chromotography. Samples of 2, 4 TDI were collected by bubbling air through a series of impingers, each containing 10 ml of toluene. Concentrations down to 0.05 naograms of TDI per 5 µ1 portion of impinger liquid have been accurately measured. Using newer more sensitive electrometers, the possibility exists for measuring 1.0 picograms of TDI per 5 µ1 of toluene absorber. Valid TDI in air determinations as low as 0.005 ppm (one-fourth the current ceiling Threshold Limit Value) may be obtained in only 3 minutes of sampling time. Potentially, the time required for sampling may be reduced to 3 seconds, the.nominal time of one human respiratory cycle. This latter time period provides proper definition to ceiling values of importance in measuring pulmonary effects.