Chemistry Department, Université du Québec à Montréal, PO Box 8888 Downtown Station, Montreal, H3C 3P8, Canada.
Institut de recherche Robert-Sauvé en santé et en sécurité du travail, 505 boul. De Maisonneuve Ouest, Montréal, Québec, H3A 3C2, Canada.
Anal Bioanal Chem. 2020 Jan;412(3):753-762. doi: 10.1007/s00216-019-02295-y. Epub 2019 Dec 24.
4,4'-Methylenediphenyldiisocyanate (MDI), toluenediisocyanate (2,4-TDI and 2,6-TDI), and 1,6'-hexamethylenediisocyanate (HDI) are all commonly used in the production of polyurethane-containing materials in different application areas. Workers exposed occupationally to these compounds may develop sensitization with the potential to lead to asthma. Isocyanates are metabolized in vivo by conjugation to macromolecules and/or by acetylation prior to being eliminated in urine. The hydrolysis of urine samples releases free amine compounds from these metabolites as biomarkers of exposure, specific to each parent isocyanate: 4,4'-methylenedianiline (MDA), toluenediamine (2,4-TDA and 2,6-TDA), and hexamethylenediamine (HDA). To address the need for a validated method that could be used for the simultaneous determination of biomarkers of aliphatic and aromatic isocyanates to monitor occupational exposure based on recommended thresholds, we have developed an UPLC-MS/MS method for the quantitation of MDA, TDA isomers, and HDA following acid hydrolysis, solid-phase extraction, and derivatization of urine samples. Free amine compounds were derivatized with acetic anhydride to augment chromatographic retention and signal intensity. The method was developed considering the biological guidance value (BGV) of MDA at 10 μg L, and biological exposure indices (BEI) of TDA isomers and HDA at 5 μg g and 15 μg g creatinine, respectively. Limits of detection allowed monitoring down to 6% of BGV/BEI, with precision within 8%. The accuracy and reliability of the method were assessed using inter-laboratory reference samples and deemed acceptable based on three rounds of measurements. This novel method has therefore been proven as useful for occupational safety and health assessments. Graphical Abstract.
4,4'-亚甲基二苯基二异氰酸酯（MDI）、甲苯二异氰酸酯（2,4-TDI 和 2,6-TDI）和 1,6'-己二异氰酸酯（HDI）在不同应用领域的含聚氨酯材料的生产中都有广泛应用。职业接触这些化合物的工人可能会发生致敏，从而导致哮喘。异氰酸酯在体内通过与大分子结合或乙酰化代谢，然后在尿液中排出。尿液样本的水解会将这些代谢物中的游离胺化合物释放出来，作为暴露的生物标志物，每个母体异氰酸酯都有其特异性：4,4'-亚甲基二苯胺（MDA）、甲苯二胺（2,4-TDA 和 2,6-TDA）和己二胺（HDA）。为了解决需要一种经过验证的方法，以便根据推荐的阈值，同时测定生物标志物来监测职业暴露的问题，我们开发了一种基于超高效液相色谱-串联质谱（UPLC-MS/MS）的方法，用于酸水解、固相萃取和衍生化尿液样品后，定量测定 MDA、TDA 异构体和 HDA。游离胺化合物与乙酸酐衍生化，以增加色谱保留和信号强度。该方法的开发考虑了 MDA 的生物指导值（BGV）为 10μg/L，以及 TDA 异构体和 HDA 的生物暴露指数（BEI）分别为 5μg/g 和 15μg/g 肌酐。检测限允许监测到 BGV/BEI 的 6%，精密度在 8%以内。该方法的准确性和可靠性通过实验室间参考样品进行评估，并在三轮测量后被认为是可接受的。因此，该新方法已被证明对职业安全和健康评估有用。
