Wang Yan, Castro Mafalda, Tisler Selina, Jørgensen Mathias B, Kilpinen Kristoffer, Devers Jason, Luckute Austeja, Lundqvist Johan, Christensen Jan H, Cedergreen Nina
Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark.
BIOFOS A/S, Copenhagen, Denmark.
Environ Toxicol Chem. 2025 Aug 1;44(8):2154-2165. doi: 10.1093/etojnl/vgaf127.
Nontoxic blank samples are a prerequisite in effect-directed analysis to ensure that any measured bioassay activity stems from chemicals in the environmental sample, and not from chemicals added through the sampling and sample preparation procedures. In a study on wastewater, solid phase extraction (SPE) blank samples, prepared by extracting clean water (such as tap water, demineralized water, etc.) using the same methodology as real wastewater, showed toxic effects in algae, daphnia, and in vitro bioassays. The aim of this study was to pinpoint the origin of the chemicals responsible for the observed toxicity, and to provide guidance on how to remediate their occurrence. Analysis revealed that the elution solvents optimized for SPE, composed of methanol (MeOH), NH4OH, and formic acid, constituted a significant source of toxicity, even when evaporated to dryness. Ammonium was the primary source of toxicity in the algae assay. Formic acid released toxic metal ions from the system and SPE materials, particularly Cu and Zn, which strongly affected daphnia. Switching to pure MeOH as the elution solvent alleviated most of the toxicity, although some metals remained. Further reductions in toxicity were achieved by replacing ultra-pure water with an ion-rich artificial freshwater medium for preparing blank samples. Three tested SPE materials (graphitized carbon, hydrophilic-lipophilic balance, and ENV+) released unidentified toxic chemicals correlating with algae toxicity and estrogen receptor activity, but these could be eliminated through extensive MeOH washing before packing the cartridges. Nontoxic levels of plasticizers were detected from system components. In conclusion, altering SPE elution solvents, washing SPE materials, and using artificial freshwater as blanks minimized the release of chemicals and ensured nontoxic blank samples.
无毒空白样品是效应导向分析的前提条件，以确保任何测得的生物测定活性源于环境样品中的化学物质，而非来自采样和样品制备过程中添加的化学物质。在一项关于废水的研究中，通过使用与实际废水相同的方法提取清洁水（如自来水、去离子水等）制备的固相萃取（SPE）空白样品，在藻类、水蚤和体外生物测定中显示出毒性效应。本研究的目的是确定造成所观察到毒性的化学物质来源，并就如何补救其出现提供指导。分析表明，为SPE优化的洗脱溶剂（由甲醇（MeOH）、NH4OH和甲酸组成）即使蒸发至干，也是毒性的重要来源。铵是藻类测定中毒性的主要来源。甲酸从系统和SPE材料中释放出有毒金属离子，特别是铜和锌，这对水蚤有强烈影响。改用纯MeOH作为洗脱溶剂可减轻大部分毒性，尽管仍有一些金属残留。通过用富含离子的人工淡水介质代替超纯水来制备空白样品，进一步降低了毒性。三种测试的SPE材料（石墨化碳、亲水亲油平衡和ENV+）释放出与藻类毒性和雌激素受体活性相关的不明有毒化学物质，但这些物质可在填充小柱前通过大量MeOH洗涤消除。从系统组件中检测到无毒水平的增塑剂。总之，改变SPE洗脱溶剂、洗涤SPE材料以及使用人工淡水作为空白可最大限度地减少化学物质的释放并确保无毒空白样品。
