Molnár Karlsson Thomas, Christensen Jan H
Analytical Chemistry Group, Department of Plant and Environmental Science Faculty of Science, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark.
Anal Chem. 2025 Jul 1;97(25):13274-13281. doi: 10.1021/acs.analchem.5c01303. Epub 2025 Jun 17.
Matrix effects (MEs) challenge the reliability of target and non-target screening (NTS) in urban runoff analysis, particularly due to sample heterogeneity, which makes pooled samples inadequate for method development, validation, and ME corrections. This study investigated MEs in 21 urban runoff samples from different catchment areas, showing high variability in signal suppression (0-67% median suppression at 50× relative enrichment factor, REF). Runoff collected after prolonged dry periods ("dirty" samples) required enrichment below REF 50 to avoid suppression exceeding 50%. In contrast, "clean" samples had suppression below 30% even at REF 100. To correct residual MEs, a novel Individual Sample-Matched Internal Standard (IS-MIS) strategy consistently outperformed established ME correction methods, achieving <20% RSD for 80% of features through analysis of samples at three REFs as part of the analytical sequence to match features and internal standards. In contrast, internal standard matching with a pooled sample resulted in only 70% of features meeting this threshold (<20% RSD). Although IS-MIS requires additional analysis time (59% more runs for the most cost-effective strategy), it significantly improves accuracy and reliability, making it a viable and cost-effective solution for large-scale urban runoff monitoring. Furthermore, IS-MIS generates valuable data on peak reliability through measurements of signal intensities across multiple REFs, which can be used to remove "false" peaks and improve data preprocessing and method development in NTS.
基质效应（MEs）对城市径流分析中目标物和非目标物筛查（NTS）的可靠性提出了挑战，特别是由于样品的异质性，这使得混合样品不足以用于方法开发、验证和基质效应校正。本研究调查了来自不同集水区的21个城市径流样品中的基质效应，结果表明信号抑制存在很大差异（在50倍相对富集因子，即REF时，中位数抑制为0-67%）。长时间干旱期后收集的径流（“脏”样品）需要在低于REF 50的条件下进行富集，以避免抑制超过50%。相比之下，“干净”样品即使在REF 100时抑制也低于30%。为了校正残留的基质效应，一种新颖的个体样品匹配内标（IS-MIS）策略始终优于已有的基质效应校正方法，通过在分析序列中以三个REF对样品进行分析来匹配特征和内标，80%的特征实现了<20%的相对标准偏差（RSD）。相比之下，使用混合样品进行内标匹配时，只有70%的特征达到该阈值（<20% RSD）。尽管IS-MIS需要额外的分析时间（最具成本效益的策略运行次数增加59%），但它显著提高了准确性和可靠性，使其成为大规模城市径流监测的可行且具有成本效益的解决方案。此外，IS-MIS通过测量多个REF下的信号强度生成了关于峰可靠性的有价值数据，可用于去除“假”峰并改善NTS中的数据预处理和方法开发。
