Rapid Detection of Toluene-2,4-diisocyanate in Various Sports Fields Using Extractive Electrospray Ionization Mass Spectrometry

Plastic materials that release free toluene-2,4-diisocyanate (TDI) can be commonly found in sports venues. As the presence of TDI in the atmosphere will result in severe air pollution, the WHO has enforced strict regulations to ensure that the proportion of the free TDI monomer in the isocyanate-polymer is lower than 0.5%. In this study, ambient air samples containing trace amounts of TDI-water aerosols were collected with glass syringes on the spot and then directly injected into a home-made extractive electrospray ionization (EESI) source. The EESI source was installed on a LTQ-MS instrument for the direct analysis of samples with complex matrices. The raw samples were directly analyzed by tandem EESI-MS without any sample pretreatment under the following working conditions: spray voltage, 3 kV; capillary voltage, 21 V; and capillary temperature, 175 °C. A single sample analysis, along with tandem MS experiments for enhanced specificity, was completed within 1 s. The limit of detection was found to be less than 0.04% (n = 5, S/N = 100), considerably lower than that allowed in the air. The relative standard deviation of the analysis results was no higher than 1.4%.