Department of Chemistry, Institute of Analytical Chemistry, University of Natural Resources and Life Sciences, Vienna, Austria.
Electrophoresis. 2021 Feb;42(4):490-500. doi: 10.1002/elps.202000256. Epub 2021 Jan 6.
Nontargeted analysis of water samples using liquid chromatography combined with high-resolution mass spectrometers is an emerging approach for surface water monitoring and evaluation of water treatment processes. In this study, sample preconcentration via direct, large volume injection with 500 μL and 1000 μL injection volumes was compared to SPE regarding analytical performance parameters in targeted and nontargeted workflows. In targeted analysis, the methods were evaluated in terms of LOD and intrabatch precision of the selected compounds, whereas in nontargeted analysis, the number of detected unknown compounds, the method's intra-batch precision, and the retention time versus molecular mass pattern of the detected unknowns were evaluated. In addition, a novel intensity drift correction method was developed that is not based on quality control samples and makes use of the signals obtained for continuously infused reference compounds, which are conventionally utilized for online mass drift correction. It could be demonstrated that the new correction method significantly reduced the bias introduced by instrumental drift and is important for the reliable intercomparison of different nontargeted methods. Intercomparison of results showed that the 1000 μL large volume injection method revealed the best performance in terms of precision under repeatability conditions of measurement as well as lower LODs for targeted compound analysis. In nontargeted analysis, the SPE method detected a higher number of unknown compounds but exhibited also a higher uncertainty of measurement caused by matrix effects.
采用液相色谱与高分辨质谱联用技术对水样进行非靶向分析，是一种新兴的地表水监测和水处理工艺评价方法。本研究比较了直接大体积进样（500 μL 和 1000 μL 进样体积）与 SPE 技术在目标分析和非目标分析工作流程中的分析性能参数。在目标分析中，评估了方法对选定化合物的检出限和批内精密度的影响；在非目标分析中，评估了未知化合物的检出数量、方法的批内精密度以及未知物的保留时间与分子量图谱。此外，还开发了一种新的强度漂移校正方法，该方法不基于质量控制样品，而是利用连续注入的参考化合物的信号，这些参考化合物通常用于在线质量漂移校正。结果表明，新的校正方法显著降低了仪器漂移引起的偏差，对于不同非靶向方法的可靠比较非常重要。结果比较表明，在测量重复性条件下，1000 μL 大体积进样法在精度方面表现最佳，同时也具有更低的目标化合物分析检出限。在非目标分析中，SPE 方法检测到更多的未知化合物，但由于基质效应，测量的不确定度也更高。
