Determination of isocyanate groups in the organic intermediates by reaction-based headspace gas chromatography

This work reports on a novel method for the determination of isocyanate groups in the related organic intermediates by a reaction-based headspace gas chromatography. The method is based on measuring the CO2 formed from the reaction between the isocyanate groups in the organic intermediates and water in a closed headspace sample vial at 45 °C for 20 min. The results showed that the method has a good precision and accuracy, in which the relative standard deviation in the repeatability measurement was 5.26%, and the relative differences between the data obtained by the HS-GC method and the reference back-titration method were within 9.42%. The present method is simple and efficient and is particularly suitable to be used for determining the isocyanate groups in the batch sample analysis.