Evaluation and application of ion-trap-enhanced LC-QTOF-MS for the identification of >500 chemicals of concern in reclaimed wastewater, soil, and vegetables from Andalusia, Spain

An analytically focused workflow employing LC-QTOF-MS (with Zeno ion trap) advances trace-level HRMS screening for irrigation-water reuse monitoring by improving ion-utilization efficiency at the TOF entrance. Ion pre-accumulation increases the fraction of ions sampled at each pulse, resulting in higher fragment-ion signal and improved identification confidence; Sequential windows acquisition of all theoretical fragment ion mass spectra (SWATH®) acquisition subsequently simplifies spectra and reduces matrix interference. In this study, direct injection was applied to reclaimed-water samples only, whereas soil and crop samples were analysed after QuEChERS-based extraction/clean-up. Identification was supported by a homemade theoretical-exact mass database of 525 compounds with precursor ion and two fragments per compound. The method performance was established for 237 compounds using analytical standards on real matrices. Monitoring of reclaimed water over five months (50 samples) using our database tentatively detected 43 micropollutants, of which 27 were (frequently) detected across several samples and 23 were unequivocally identified using analytical standards. Building on this survey, we then conducted a greenhouse case study under real operating conditions, irrigated with reclaimed water from the same plant; the greenhouse soil and the harvested cucumbers from that soil were analysed. In soils, residues remained quantifiable at the post-harvest sampling point for carbendazim, carbamazepine and flubendiamide ( Per - and Polyfluoroalkyl Substances (PFAS) pesticide) and accumulation was observed for caffeine, chlorantraniliprole, azoxystrobin and tebuconazole. In crops, residues were identified at sub-μg kg −1 (carbamazepine, tramadol). The workflow shortened sample-to-result time and enabled reliable trace-level identification across reclaimed-water, soil, and crop matrices. • LC-QTOF-MS with ion trapping enables trace-level screening in reclaimed water, soil and crops. • High resolution mass spectrometry library (525 compounds) enables screening. • Monitoring under field conditions identified soils as reservoirs of micropollutants. • A case study: irrigated soil-to-crop transfer of carbamazepine and tramadol.