This paper describes quantitative methods for the determination of dimethylsulfoxide (DMSO) in equine plasma and urine based on simple precipitation and dilution followed by hydrophilic interaction liquid chromatography coupled to tandem mass spectrometry (HILIC‐MS/MS). DMSO is a polar solvent with analgesic and anti‐inflammatory properties. Its pharmacological features make it prohibited in horse racing. However, since DMSO is naturally present in the horses’ environment, international threshold values have been implemented for plasma and urine (1 and 15 µg/mL, respectively). Previously presented quantitative methods for the determination of DMSO are based on gas chromatography, thus demanding a tedious extraction step to transfer the analyte from the aqueous bodily fluid to an injectable organic solvent. The column used in the presented method was an Acquity BEH HILIC and the mobile phase was a mixture of ammonium acetate buffer and acetonitrile delivered as a gradient. Hexadeuterated DMSO (²H₆‐DMSO) was used as the internal standard. Validation was performed in the range of the international thresholds concerning selectivity, carry‐over, linearity, precision, accuracy, stability and inter‐individual matrix variation. The results fulfilled the predefined criteria and the methods were considered fit for purpose. Successful applications on real equine doping control samples were carried out with determined DMSO concentrations exceeding the international thresholds. Copyright © 2016 John Wiley & Sons, Ltd.

中文翻译：

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使用HILIC-MS / MS对马血浆和尿液中的二甲亚砜（DMSO）进行定量

本文介绍了基于简单的沉淀和稀释，然后通过亲水相互作用液相色谱-串联质谱（HILIC-MS / MS）进行定量的马血浆和尿液中二甲亚砜（DMSO）的测定方法。DMSO是具有止痛和抗炎特性的极性溶剂。它的药理特性使其禁止在赛马中使用。但是，由于DMSO自然存在于马匹的环境中，因此已针对血浆和尿液设定了国际阈值（分别为1和15 µg / mL）。先前提出的用于测定DMSO的定量方法是基于气相色谱法的，因此需要繁琐的提取步骤才能将分析物从含水体液转移到可注射的有机溶剂中。本方法中使用的色谱柱为Acquity BEH HILIC，流动相为醋酸铵缓冲液和乙腈的梯度混合物。十六氘代DMSO（² H ₆ -DMSO）作为内标。在有关选择性，残留，线性，精密度，准确性，稳定性和个体差异的国际阈值范围内进行验证。结果符合预定标准，该方法被认为适合目的。在确定的DMSO浓度超过国际阈值的情况下，成功地在实际马掺杂对照样品上进行了应用。版权所有©2016 John Wiley＆Sons，Ltd.