Abstract It is a challenge to perform target screening of metabolites on a large scale in metabolomics study using gas chromatography with mass spectrometry ( GC-MS ). Some metabolites can hardly be detected and identified in biosamples due to their low MS response or poor specificity. Moreover, synthesis and degradation of derivatized metabolites in samples made it difficult to achieve fine method stability. Our method screens 475 metabolites in a single run using GC-MS/MS in MRM mode, and both internal standard and quality control-based normalization strategies were used to correct the peak intensity. A total of 91 and 161 metabolites were detected in plasma and urine, respectively. The method was validated to have fine linearity range and intra-day and inter-day stability. The method was applied to a pilot study, and this study investigated the metabolic perturbation in rats after fluorochloridone ( FLC ) administration. 18 metabolites exhibited statistical significance in rat urine, and they were confirmed to be associated with FLC treatment, where the upregulation of glucose, lactose, and galactose is potentially linked to oxidative stress reaction. This study has proved its value in large-scale detection of metabolites in biosamples using GC-MS/MS with high sensitivity, specificity, and stability. We hope that our study can promote the GC-MS-based metabolomics studies.
Dong Zhao,Hongyu Chen,Shuo Shen,Enyu Lu,Junlong Feng,Hui Zhi,Lei Wang,Wei Li
Flurochloridone (FLC) is a pyrrolidone herbicide used to control broad-leaved weeds in various crop fields. However, there is still a lack of comprehensive research on the environmental fate of the Qinghai-Tibet Plateau (QTP) and the toxicity of its potential transformation products (TPs). In this study, laboratory experiments were conducted to investigate the degradation kinetics, pathways, and toxicity of FLC’s TPs. Nine TPs were identified in soil using Ultra-Performance Liquid Chromatography Quadrupole-Orbitrap Mass Spectrometry (UPLC-Q-Exactive Orbitrap MS) and Compound Discoverer software, employing suspect and nontarget screening strategies. The initial report of two TPs, TP204, and TP191 was confirmed through the acquisition or synthesis of their standards. High Performance Liquid Chromatography coupled with Tandem Mass Spectrometry (HPLC-MS/MS) was subsequently used for further quantification of these TPs in all samples under examination. The primary transformation reactions of FLC in the environment include oxidative dechlorination, reductive dechlorination, reductive defluorination, acetylation, and hydrolysis. Predictive assessments via ECOSAR, alongside empirical laboratory experiments, revealed that most novel TPs exhibit significantly lower acute toxicity towards Danio rerio , Daphnia magna Straus , and Algae compared to FLC. However, TP204 demonstrated neutral chronic toxicity towards Daphnia magna Straus and Green algae , potentially posing a latent threat to aquatic ecosystems. These results are crucial for elucidating the environmental fate of FLC, assessing environmental risks, and guiding scientific and reasonable use. This research holds significant importance for the ecological environment protection in the Tibetan Plateau region.
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