Background

Therapeutic drug monitoring (TDM) of antidepressants is important to ensure compliance and to rule out pharmacokinetic abnormalities. Therefore, reliable methods for quantification are important for clinical laboratories. Most of the currently used mass spectrometry methods use triple quadrupoles as mass analyzers. We aimed to develop a method using high-resolution mass spectrometry (HRMS) and wanted to test the suitability of this analyzer for quantitative TDM assays. This would be beneficial since HRMS instruments can also be used for metabolomics and protein analysis and, thus, many different analyses could be run on one instrument.

Methods

After manual protein precipitation of serum samples, further sample clean-up was achieved using a Turbo Flow column preconnected to the analytical LC column. Stable isotope-labelled counterparts of the target analytes were used as internal standards. For detection, we used a Q Exactive Focus Orbitrap mass spectrometer operating in full-scan mode. Ionization was performed in positive ESI.

Results

Accuracy, recovery, and matrix effect were acceptable for all analytes. The method demonstrated outstanding precision (within-run imprecision <4.5%, between-run imprecision <7.5%). The selectivity of the method was ensured by chromatographic separation of all isobaric compounds. Close agreement between Orbitrap and triple stage based quantification was observed in a comparison measurement of leftover patient samples.

Conclusions

We have established a selective method for the quantification of antidepressants with outstanding precision using a high-resolution Orbitrap mass spectrometer. The applicability of HRMS instruments to TDM was demonstrated.

中文翻译：

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用于抗抑郁药治疗药物监测的半自动同位素稀释高分辨率质谱分析

背景

抗抑郁药的治疗药物监测 (TDM) 对于确保依从性和排除药代动力学异常非常重要。因此，可靠的定量方法对临床实验室很重要。目前使用的大多数质谱方法都使用三重四极杆作为质量分析器。我们旨在开发一种使用高分辨率质谱 (HRMS) 的方法，并希望测试该分析仪对定量 TDM 测定的适用性。这将是有益的，因为 HRMS 仪器也可用于代谢组学和蛋白质分析，因此可以在一台仪器上运行许多不同的分析。

方法

在对血清样品进行手动蛋白质沉淀后，使用预先连接到分析 LC 色谱柱的 Turbo Flow 色谱柱实现进一步的样品净化。目标分析物的稳定同位素标记的对应物用作内标。对于检测，我们使用了在全扫描模式下运行的 Q Exactive Focus Orbitrap 质谱仪。在正 ESI 中进行电离。

结果

所有分析物的准确度、回收率和基质效应均可接受。该方法表现出出色的精密度（批内不精密度<4.5%，批间不精密度<7.5%）。该方法的选择性是通过色谱分离所有同量异位化合物来保证的。在剩余患者样本的比较测量中观察到 Orbitrap 和基于三阶段的量化之间的密切一致性。

结论

我们已经建立了一种使用高分辨率 Orbitrap 质谱仪以出色的精度定量抗抑郁药的选择性方法。证明了 HRMS 仪器对 TDM 的适用性。