2.3. Analysis
Analysis of the target pesticides in water was performed by on online
solid phase extraction–liquid chromatography–tandem mass spectrometry (SPE–LC–MS/MS) as described in Köck-Schulmeyer et al. 2012, 2013).
Briefly, 5 mL of the water samples (previously filtered and spiked with the deuterated surrogate standards at 200 ng L−1) and the standard calibration solutions were extracted with an automated online SPE sample processor, Prospekt-2 (Spark Holland, Emmen, The Netherlands), connected in series with the LC–MS/MS instrument, using two types of disposable trace enrichment polymeric cartridges (Hysphere Resin GP and PLRP-s, both from Spark Holland). The
Hysphere Resin GP cartridge was used for the extraction of 6 pesticides that were measured in the negative ionisation (NI) mode, and the PLRP-s cartridge was used for the extraction of the pesticides that were measured in the positive ionisation (PI)mode (19 compounds)
(see Table 1). After sample loading, the cartridges were washed with 1 mL of water and eluted with the chromatographic mobile phase.