Background

LC–MS/MS allows for many measurands monitoring different mass transitions simultaneously. So far, such alternative mass transitions are usually assessed as “quantifier and qualifier ions” in order to rule out interferences in individual samples. However, quantification can also be based on assessment of alternative mass transitions for both the measurand and its internal standard, with two distinct results for one injection of an individual sample. These paired results can be averaged. The aim of this study was to determine the potential impact of this averaging approach on measurement imprecision.

Methods

We studied the impact of averaging results from different transitions for four exemplary measurands (linezolid (LIN), piperacillin (PIP), voriconazole (VOR), ethylglucuronide (ETG)). Intra-batch studies were performed with 21 injections of single clinical samples in sequence for each analyte (LIN, PIP, VOR), and a between-batch study with evaluation of data from routine QC samples from 20 series over 20 weeks (ETG). CVs and their confidence intervals were assessed comparatively for quantification based on single transitions, and for averaged results from these two transitions, respectively.

Results

In all data sets, we observed lower CVs for the averaged results compared to the results obtained from single mass transitions. CVs from averaged results were up to 39.4% lower compared to the CVs observed for results obtained from single transitions for the respective measurands.

Conclusion

Averaging of quantification results obtained from separate mass transitions acquired simultaneously in ID-LC-MS/MS seems to have the potential to minimize the measurement imprecision for different measurands in short- and long-term settings.

中文翻译：

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在 ID-LC-MS/MS 中对来自不同、同时采集的质量转换的结果进行平均 – 对测量不精确度的潜在影响

背景

LC-MS/MS 允许同时监测不同质量转换的许多被测量。到目前为止，此类替代质量转换通常被评估为“定量离子和定性离子”，以排除单个样品中的干扰。然而，量化也可以基于对被测量及其内标的替代质量转换的评估，对于单个样品的一次注射具有两个不同的结果。这些配对结果可以平均。本研究的目的是确定这种平均方法对测量不精确度的潜在影响。

方法

我们研究了四种示例性被测量（利奈唑胺 (LIN)、哌拉西林 (PIP)、伏立康唑 (VOR)、乙基葡糖苷酸 (ETG)）的不同跃迁平均结果的影响。对每种分析物（LIN、PIP、VOR）依次注射 21 次单一临床样品进行批次内研究，并在 20 周内对来自 20 个系列的常规 QC 样品的数据进行批间研究（ETG）。CV 和它们的置信区间被比较评估为基于单个转换的量化，以及这两个转换的平均结果，分别。

结果

在所有数据集中，我们观察到平均结果的 CV 低于从单个质量转换获得的结果。与从各个被测量的单个跃迁获得的结果观察到的 CV 相比，平均结果的 CV 降低了 39.4%。

结论

在 ID-LC-MS/MS 中同时获得的单独质量转换获得的量化结果的平均值似乎有可能最大限度地减少短期和长期设置中不同被测量的测量不精确度。