Non-target screening IDA and SWATH acquisition techniques comparison in river sediment and mussels

Abstract

The aquatic ecosystems are dynamic environments that are frequently affected directly or indirectly by anthropogenic discharge of contaminants. A large number of contaminants can be present in their different compartments and the application of a non-target screening approach provides the opportunity to expand the knowledge on the occurrence of any type of low-molecular-weight organic pollutants and a deep insight into the state of pollution. In this study, detailed liquid chromatography-quadrupole time-of-flight mass spectrometry (LCQqTOF-MS) non-target screening analyses have been applied to mussels (Mytilus Galloprovincialis) and riverine sediment of the Turia River Basin, in Eastern Spain. This river passes across the metropolitan area of Valencia being exposed to different contaminants. The extraction of the sediments was carried out using a mixture of McIlvaine buffer (pH 5.4) and methanol by ultrasound-assisted extraction (UAE). Then, extracts were cleaned up by the solid phase extraction (SPE) with StrataTMX cartridges and analytes were eluted using methanol-dichloromethane at gravity flow. In the case of the mussel samples, were extracted using the QuEChERS method, with a mixture of Acetonitrile, water, MgSO4, NaCl, 2Na2C6H6O7 and C6H9Na3O9, then shaken and centrifuged to obtain the supernatant. Sensitive and selective liquid chromatography–mass spectrometry (LC–MS) analysis is a powerful and essential tool for contaminant identification in environmental studies. An MS (or tandem, MS/MS) mass spectrum is acquired from the fragmentation of a precursor ion by multiple methods including information-dependent acquisition (IDA) and sequential window acquisition of all theoretical fragment-ion spectra (SWATH). To determine different efficiency between this two techniques their capabilities to produce comprehensive MS2 data by assessing both contaminant MS2 acquisition hit rate and the quality of MS2 spectra were compared. The SWATH method is able to identify a higher number of compounds in all the analyzed samples. However, the quality of the acquired MS2 spectra decreased in SWATH. The method used is suitable to detect different emergent pollutants in biotic and abiotic matrices as river sediment and mussels.