Analysis and occurrence of selected medium to highly polar pesticides in groundwater of Catalonia (NE Spain): An approach based on on-line solid phase extraction–liquid chromatography–electrospray-tandem mass spectrometry detection

The present work describes an automated methodology based on on-line solid phase extraction–liquid chromatography–electrospray-tandem mass spectrometry (on-line SPE–LC–ESI-MS/MS) for the determination of 22 medium to highly polar pesticides in groundwater, and its application to the analysis of 133 samples collected from different aquifers of Catalonia (NE Spain), in areas where agricultural practice is significant. Sample preconcentration was performed by passing 5 mL of the sample through PLRPs cartridges (for analysis of 16 pesticides measured in the positive ionization mode) and through Hysphere-Resin GP cartridges (for analysis of six pesticides measured in the negative ionization mode). Further LC–MS/MS determination was performed in the selected reaction monitoring (SRM) mode, by recording two SRM transitions per compound, thus obtaining four identification points. The methodology developed allows the determination of the target compounds at the pg or low ng L−1 level with satisfactory precision (relative standard deviations lower than 16%) and accuracy (recovery percentages higher than 75%) and is well suited for routine monitoring. Its application to various groundwater samples from Catalonia has revealed simazine, diuron and atrazine (present in more than 70% of the samples) as the most ubiquitous compounds. Approximately 16% of the samples investigated had individual pesticides levels above 100 ng L−1 and 7% presented total pesticides levels above 500 ng L−1. Concentrations higher than 100 ng L−1 were found for all triazines studied but cyanazine, the phenylureas diuron, linuron and chlortoluron, the target chloroacetanilides alachlor and metolachlor, and the organophosphate dimethoate in a few samples. Three and eight out of the 16 investigated groundwater bodies presented total pesticide levels exceeding the EU quality standards in terms of individual and total pesticide concentrations, 100 and 500 ng L−1, respectively.

Bibliographic Details

Main Authors:	Postigo, Cristina, López de Alda, Miren, Barceló, Damià, Ginebreda Martí, Antoni, Garrido, Teresa, Fraile, Josep
Format:	artículo biblioteca
Language:	English
Published:	Elsevier 2010
Subjects:	Groundwater, Pesticides, Liquid chromatography, Mass spectrometry, Water quality,
Online Access:	http://hdl.handle.net/10261/45156
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