Simultaneous determination of eight neonicotinoid insecticides and five metabolites in water samples by liquid chromatography‐tandem mass spectrometry unveils an overlooked risk.

Neonicotinoids (NEOs), highly selective toward insect nicotinic acetylcholine receptors, are extensively used due to their effectiveness against pests and relative non‐toxicity to vertebrates. However, their prolonged persistence in soil and water has led to frequent detection in food and environmental samples, posing significant environmental and health concerns. Recent research indicates these pesticides infiltrate aquatic ecosystems, threatening aquatic life and human health. Here, we improved the ultra‐performance liquid chromatography‐mass spectrometry method for detecting NEOs in water samples, increasing its sensitivity to fulfill forthcoming detection needs. This approach enables the simultaneous quantification of eight NEOs and five NEO metabolites in diverse water sources, including tap, surface, groundwater, sewage, and seawater. Our method achieves remarkably low detection limits for direct injection (0.78–1.7 ng/L) and solid‐phase extraction methods (0.13–0.25 ng/L). Critically, our findings reveal that boiling domestic drinking water doesn't degrade NEOs; instead, it increases their concentration due to water evaporation. A 6‐min boiling period can amplify pesticide concentration by 4–5 times, presenting a significant hazard in culinary practices of specific regions where prolonged cooking could lead to alarmingly high levels of these insecticides. This research underscores the importance of monitoring and mitigating NEO contamination in water sources to safeguard environmental and public health. [ABSTRACT FROM AUTHOR]