工作场所空气中二苯基甲烷二异氰酸酯的气相色谱法测定

Determination of Diphenylmethane Diisocyanate(MDI) in Gas of Workplace by Gas Chromatography

目的 :通过对工作场所空气中二苯基甲烷二异氰酸酯(MDI)气相色谱测定方法开展研究,为今后同行开展工作提供参考。方法 :本次研究空气中气溶胶态二苯基甲烷二异氰酸酯(MDI)用装有酸溶液的冲击式吸收管采集,水解后,生成甲苯二胺(MDA),在碱性条件下用甲苯萃取,经七氟丁酸酐衍生后,取甲苯萃取液进样,经TR-5色谱柱分离,ECD检测器检测,以保留时间定性,峰高或峰面积定量。结果 :通过采取上述方法对工作场所空气中二苯基甲烷二异氰酸酯(MDI)开展气相色谱测定,不但可以获得较好的分离效果,同时其平均解吸效率也较高,并且重现性较优(相对标准偏差是1.4%~1.9%)。结论 :在工作场所空气中MDI气相色谱测定上采用上述方法能够在平均解吸效率、分离效果和重现等方面具取得很好的效果,因而值得同行参考借鉴。

Objective ：To study the method of gas chromatography of diphenylmethane diisocyanate（MDI）in workplace air,and provide reference for future work.Method ：In this study,the aerosol diphenylmethane diisocyanate（MDI）was collected in an impact absorption tube containing an acid solution.After hydrolysis,toluene diamine（MDA）was formed and extracted with toluene under alkaline conditions.After derivatization with heptafluorobutyric anhydride,the toluene extract was injected,separated by a TR-5 column,detected by an ECD detector,and characterized by retention time,peak height or peak area.RESULTS ：By using the above method to determine the diphenylmethane diisocyanate（MDI）in the workplace air,not only can better separation results,but also the average desorption efflciency is higher,and the reproducibility is better（The relative standard deviation is 1.4%-1.9%）.Conclusion ：According to the author＇s research,the above method can achieve good results in the average desorption efflciency,separation effect and reproducibility in MDI gas chromatographic measurement in workplace air,so it is worthy of reference.