State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, No. 71 East Beijing Road, Nanjing, 210008, China.
University of Chinese Academy of Science, Beijing, 100049, China.
Anal Bioanal Chem. 2024 Aug;416(19):4237-4247. doi: 10.1007/s00216-024-05361-2. Epub 2024 Jun 7.
The continuous introduction of micropollutants into the environment through livestock farming, agricultural practices, and wastewater treatment is a major concern. Among these pollutants are synthetic sulfonamide antibiotics such as sulfamethoxazole, which are not always fully degraded and pose a risk of fostering antimicrobial resistance. It is challenging to assess the degradation of sulfonamides with conventional concentration measurements. This study introduces compound-specific isotope analysis of nitrogen isotope ratios at natural abundances by derivatization-gas chromatography hyphenated with isotope ratio mass spectrometry (derivatization-GC-IRMS) as a new and more precise method for tracing the origin and degradation of sulfonamides. Here, sulfamethoxazole was used as a model compound to develop and optimize the derivatization conditions using (trimethylsilyl)diazomethane as a derivatization reagent. With the optimized conditions, accurate and reproducible δN analysis of sulfamethoxazole by derivatization-GC-IRMS was achieved in two different laboratories with a limit for precise isotope analysis of 3 nmol N on column, corresponding to 0.253 µg non-derivatized SMX. Application of the method to four further sulfonamides, sulfadiazine, sulfadimethoxine, sulfadimidine, and sulfathiazole, shows the versatility of the developed method. Its benefit was demonstrated in a first application, highlighting the possibility of distinguishing sulfamethoxazole from different suppliers and pharmaceutical products.
畜牧养殖、农业实践和废水处理不断将微量污染物引入环境，这是一个主要关注点。这些污染物中包括合成的磺胺类抗生素，如磺胺甲恶唑，它们并不总是完全降解，存在促进抗微生物耐药性的风险。使用传统的浓度测量方法评估磺胺类药物的降解具有挑战性。本研究通过衍生化-气相色谱与同位素质谱联用（衍生化-GC-IRMS）介绍了自然丰度下氮同位素比值的化合物特异性同位素分析，作为一种新的、更精确的方法来追踪磺胺类药物的来源和降解。在这里，使用磺胺甲恶唑作为模型化合物，使用（三甲基硅基）重氮甲烷作为衍生化试剂来开发和优化衍生化条件。使用优化的条件，通过衍生化-GC-IRMS 对磺胺甲恶唑进行了准确且可重复的 δN 分析，两个不同实验室的同位素精确分析的限制为柱上 3 nmol N，相当于未衍生化 SMX 的 0.253 µg。该方法在另外四种磺胺类药物磺胺嘧啶、磺胺二甲氧嘧啶、磺胺二甲嘧啶和磺胺噻唑中的应用表明了该方法的通用性。在首次应用中证明了该方法的优势，突出了从不同供应商和医药产品中区分磺胺甲恶唑的可能性。
