Determination of total airborne isocyanates using tryptamine as the derivatising agent was investigated. Tryptamine derivatised isocyanates were analysed by reversed-phase high-performance liquid chromatography (HPLC). The column was equipped with dual detectors of fluorescence emission and amperometric oxidation. The characteristics of fluorescence emission and amperometric oxidation of tryptamine were retained even after its reaction with isocyanates. With this unique behaviour, all tryptamine derivatised isocyanates can be quantified using HPLC by employing a single, pure derivative, such as tryptamine derivatised hexamethylene diisocyanate as the calibration standard. This is especially important for analysing polymeric isocyanates when identical calibration standards are not always available. The applicability of this method for air sampling was evaluated by comparison with the established method of Bagon et al. involving 1-(2-methoxyphenyl)piperazine. Simulation of air sampling was performed in a Test Atmosphere Generation System by the vaporisation of toluene diisocyanate. Satisfactory results were obtained, indicating the applicability of this technique for the determination of total airborne isocyanates.

Tryptamine was investigated as a derivatising agent for the determination of airborne isocyanates. A model compound was prepared by derivatising methyl isocyanate with tryptamine. The former is the simplest isocyanate in structure and was easily vaporised, resembling most airborne isocyanates in the workplace while simulated air sampling was conducted. Tryptamine contains an indolyl moiety and undergoes fluorescence and amperometric oxidation.Reversed-phase high-performance liquid chromatographic separation was employed for the isocyanate derivative in conjunction with dual detection characterised by fluorescence and amperometric oxidation. Both detection methods were highly specific with similar sensitivities. Therefore, this method would also provide the desired information for confirmatory purposes in addition to the extremely low level of quantification.

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Carbon disulphide reacts readily with primary alkylamines to yield dithiocarbamates. When injected into the heated injection port of a gas chromatograph, the dithiocarbamates yield the corresponding isothiocyanates. This reaction provides a simple and elegant derivatisation for quantifying, and also confirming the identify of, the primary alkylamines.

A highly sensitive and specific gas chromatographic-mass spectrometric (GC-MS) assay for the determination of 4,4'-methylenebis(2-chloroaniline) (MBOCA) in urine is reported. It is based on the solvent extraction of the hydrolysed MBOCA conjugates, together with deuterium-labelled benzidine-d8 added as an internal standard, and a two-phase derivatization procedure involving use of pentafluoropropionic anhydride in the presence of ammonia as the phase-transfer catalyst. The reaction is complete within 2 min at room temperature. The pentafluoropropyl derivatives are determined by use of capillary column GC-MS with selected-ion monitoring in the negative ion chemical ionization mode. The lower limit of detection for MBOCA was 1 microgram dm-3 and the calibration graph showed linearity between 10 and 250 micrograms dm-3. The recovery of the analyte added to pooled urine was above 86%. Thirty urine specimens from workers employed in a polyurethane-producing plant were analysed for MBOCA by this method.