On-line solid-phase extraction method for determination of triazine herbicides and degradation products in seawater by ultra-pressure liquid chromatography-tandem mass spectrometry

- Determination of nine triazine herbicides and eight degradation products in seawater.
- A method using on-line SPE coupled with UPLC-tandem mass spectrometry was developed.
- Limits of quantification (LOQ) ranged from 0.023 to 0.657 μg L−1.
- Analytical recoveries and precision were satisfactory for all compounds.

A fast, simple, selective and sensitive method has been developed for the determination of nine triazine herbicides (ametryn, atrazine, cyanazine, prometryn, propazine, simazine, simetryn, terbuthylazine and terbutryn) and eight degradation products (desethyl atrazine, desethyl-desisopropyl atrazine, desethyl 2-hydroxyatrazine, desethyl terbuthylazine, desisopropyl atrazine, desisopropyl 2-hydroxyatrazine, 2-hydroxyatrazine and 2-hidroxyterbuthylazine) in seawater samples. On-line solid-phase extraction coupled with ultra-pressure liquid chromatography-tandem mass spectrometry was employed for simultaneous analysis of all compounds in 11 min. Validation parameters were studied through the estimation of the limits of detection and quantification, calibration curves and precision. Limits of quantification ranged from 0.023 to 0.657 μg L−1. Good linearity was obtained for all compounds with R2 > 0.99 in all cases. Furthermore, inter-day precision (0-2.1%) and intra-day precision (0-3.9%) were shown to be satisfactory. On-line solid-phase extraction recoveries in spiked unpolluted seawater sample were evaluated and acceptable values (80.3-99.8%) with adequate RSD (0.1-3.1%) were found.Finally, the proposed method was applied to the analysis of the target compounds in seawater samples collected from seawater nearby a zone of intensive horticulture of Matosinhos (Portugal). The concentrations of the herbicides were below the limit of detection in all cases.