In recent years, the commercialization of hybrid ion mobility-mass spectrometers and their integration in traditional LC-MS workflows provide new opportunities to extend the current boundaries of targeted and non-targeted analyses. When coupled to LC-MS, ion mobility spectrometry (IMS) provides a novel characterization parameter, the so-called averaged collision cross section (CCS, Ω), as well as improves method selectivity and sensitivity by the separation of isobaric and isomeric molecules and the isolation of the analytes of interest from background noise. In this work, we have explored the potential and advantages of this technology for carrying out the determination of phase II steroid metabolites (i.e. androgen and estrogen conjugates, including glucuronide and sulfate compounds; n = 25) in urine samples. These molecules have been selected based on their relevance in the fields of chemical food safety and doping control, as well as in metabolomics studies. The influence of urine matrix on the CCS of steroid metabolites was evaluated in order to give more confidence to current CCS databases and support its use as complementary information to retention time (Rt) and mass spectra for compound identification. Samples were only diluted 10-fold with aqueous formic acid (0.1%, v/v) prior analysis. Only an almost insignificant effect of adult bovine urine matrix on the CCS of certain steroid metabolites was observed in comparison with calve urine matrix, which is a less complex sample. In addition, high accuracy was achieved for CCS measurements carried out over four months (ΔCCS < 1.3% for 99.8% of CCS measurements; n = 1806). Interestingly, it has been observed that signal-to-noise (S/N) ratio could be improved at least 2 or 7-fold when IMS is combined with LC-MS. In addition to the separation of isomeric steroid pairs (i.e. etiocholanolone glucuronide and epiandrosterone glucuronide, as well as 19-noretiocholanolone glucuronide and 19-norandrosterone glucuronide), steroid-based ions were also separated in the IMS dimension from co-eluting matrix compounds that presented similar mass-to-charge ratio (m/z). Finally, based on CCS measurements and as a proof of concept, 17α-boldenone glucuronide has been identified as one of the main metabolites resulted from boldione administration to calves.

中文翻译：

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离子淌度质谱法对尿液中 II 相类固醇代谢物进行靶向和非靶向分析的潜力


近年来，混合离子淌度-质谱仪的商业化及其在传统 LC-MS 工作流程中的集成为扩展当前靶向和非靶向分析的界限提供了新的机会。当与 LC-MS 联用时，离子迁移谱 (IMS) 提供了一种新颖的表征参数，即所谓的平均碰撞截面 (CCS, Ω)，并通过分离同量异位和同分异构分子来提高方法的选择性和灵敏度。将感兴趣的分析物与背景噪声隔离。在这项工作中，我们探索了该技术在尿液样本中测定 II 期类固醇代谢物（即雄激素和雌激素结合物，包括葡萄糖醛酸和硫酸盐化合物；n = 25）的潜力和优势。这些分子的选择是基于它们在化学食品安全和兴奋剂控制以及代谢组学研究领域的相关性。评估尿液基质对类固醇代谢物 CCS 的影响，以便为当前 CCS 数据库提供更多信心，并支持其用作保留时间 (Rt) 和质谱的补充信息以进行化合物鉴定。分析前样品仅用甲酸水溶液（0.1%，v/v）稀释 10 倍。与小牛尿液基质相比，成年牛尿液基质对某些类固醇代谢物的 CCS 的影响几乎微不足道，小牛尿液基质是一种不太复杂的样品。此外，四个月内进行的 CCS 测量实现了高精度（99.8% 的 CCS 测量ΔCCS < 1.3%；n = 1806）。有趣的是，据观察，当 IMS 与 LC-MS 结合时，信噪比 (S/N) 可以提高至少 2 或 7 倍。 除了异构类固醇对（即乙硫胆醇酮葡萄糖醛酸和表雄酮葡萄糖醛酸，以及 19-去甲睾酮葡萄糖醛酸和 19-去甲雄酮葡萄糖醛酸）的分离之外，还在 IMS 维度上从共洗脱基质化合物中分离出基于类固醇的离子。相似的质荷比 (m/z)。最后，根据 CCS 测量并作为概念证明，17α-boldenone 葡萄糖醛酸苷已被确定为给犊牛施用 Boldenone 产生的主要代谢物之一。