Methotrexate (MTX) is widely used as antineoplastic drug (AD) and as an immunosuppressive. As a result, many healthcare professionals are exposed to this drug which is classified as dangerous to handle due to its reproductive toxicity in humans. Since the 1990 s, cases of internal contamination of professionals handling this molecule have been reported in the literature and even recently MTX was detected in the urine of professionals. To date, there is no toxicological reference value for occupational exposure to MTX. Given the toxicity of this molecule, the internal contamination of professionals must be reduced and kept as low as possible according to the ALARA principle (as low as reasonably achievable). The aim of this work was to develop an UHPLC-MS/MS method in MRM (Multiple Reaction Monitoring) and MRM³ modes for routine application in MTX occupational biomonitoring. Good linearity (r greater than 0.997), precision (CV < 15 %), and accuracy (94.97-97.80% of the nominal value in MRM mode; 105.90-112.25% in MRM³ mode) were achieved. This method is reliable with high specificity and high sensitivity especially in MRM³ mode and has better LOD and LLOQ (1 ng/L and 2.5 ng/L) than published methods to date. The MRM³ mode increases the signal-to-noise ratio compared to the MRM mode.

It was then applied routinely for the biological monitoring of healthcare professionals exposed to methotrexate. One hundred and seventeen urine samples from 93 healthcare professionals occupationally exposed to methotrexate were analyzed. Fifteen healthcare professionals (16.1 %) were found to be contaminated with methotrexate. Urine concentration levels ranged from 2.5 to 380 ng/L with a median value of 8.9 ng/L. Such efficient analytical tool is essential for the routine biological monitoring of healthcare professionals exposed to methotrexate. It also enables the traceability of occupational exposure to this molecule and the evaluation of the effectiveness of preventive measures such as individual and collective protective equipment.

甲氨蝶呤 (MTX) 被广泛用作抗肿瘤药物 (AD) 和免疫抑制剂。结果，许多医疗保健专业人员接触到这种药物，由于其对人类的生殖毒性，这种药物被归类为危险品。自 1990 年代以来，文献报道了处理该分子的专业人员内部污染的案例，甚至最近在专业人员的尿液中检测到 MTX。迄今为止，对于 MTX 的职业暴露没有毒理学参考值。鉴于这种分子的毒性，必须减少专业人员的内部污染，并根据 ALARA 原则将其保持在尽可能低的水平（合理可实现的低水平）。这项工作的目的是在 MRM（多反应监测）和 MRM 中开发一种 UHPLC-MS/MS 方法^{MTX职业生物监测中常规应用的3}种模式。实现了良好的线性（r 大于 0.997）、精密度（CV < 15 %）和准确度（在 MRM 模式下为标称值的 94.97-97.80%；在 MRM ³模式下为 105.90-112.25%）。该方法可靠，具有高特异性和高灵敏度，尤其是在 MRM ³模式下，并且比迄今为止已发布的方法具有更好的 LOD 和 LLOQ（1 ng/L 和 2.5 ng/L）。与 MRM 模式相比， MRM ³模式提高了信噪比。

然后将其常规应用于接触甲氨蝶呤的医疗保健专业人员的生物监测。分析了来自 93 名职业接触甲氨蝶呤的医疗保健专业人员的 117 份尿液样本。发现 15 名医疗保健专业人员 (16.1 %) 被甲氨蝶呤污染。尿液浓度范围为 2.5 至 380 ng/L，中值为 8.9 ng/L。这种高效的分析工具对于接触甲氨蝶呤的医疗保健专业人员的常规生物监测至关重要。它还可以追踪该分子的职业暴露情况，并评估预防措施的有效性，例如个人和集体防护设备。