Determination of selected pesticides in environmental water by employing liquid-phase microextraction and liquid chromatography–tandem mass spectrometry

Abstract

An optimised extraction and cleanup method for the analysis of pesticide in natural water samples is presented. Sixteen pesticides of different polarity and from the different chemical classes (organophosphates, triazines, benzimidazoles, carbamates, carbamides, neonicotinoides, methylureas, phenylureas and benzohydrazides), most frequently used in Serbia, were selected for the analysis. Liquid-phase microextraction in a single hollow fibre (HF-LPME) has been applied for sample preparation. The concentrations of pesticides were determined using HPLC-MS/MS method with electrospray ionisation. The extraction behaviour and selection of the experimental conditions was predicted based on log D and pK(a) values of targeted pesticides, which were calculated applying the computer software ACD/Labs PhysChem Suite v12. The influence of the donor pH and concentration of pesticides, organic phase composition as well as the extraction time on the extraction efficiency was investigated. Optimum extraction conditions were evaluated with respect to the investigated parameters of the extraction. The extraction method was validated for 10 out of 16 studied pesticides. Linear range of the pesticides was 0.1-5 microg L(-1) with the correlation coefficient from 0.991 to 0.9998, and the relative standard deviation for three standard measurements was between 0.2 and 11.8%. The limits of detections ranged from 0.026 to 0.237 microg L(-1) and the limits of quantifications from 0.094 to 0.793 microg L(-1). The optimised two-phase HF-LPME method was successfully applied for determination of moderately polar as well low-polar pesticides in the environmental water samples.

Liquid-phase membrane extraction of targeted pesticides from manufacturing wastewaters in a hollow fibre contactor with feed-stream recycle

“…They all exist in uncharged form over a wide pH range (2-9), since they are either very week acids or very week bases [21]. The composition of organic phase was found to significantly affect the removal efficiency of pesticides from the aqueous phase [21]. TOPO agent is able to form hydrogen-bound complexes with various solutes due to a lone pair of electrons on the oxygen atom, which can enhance the extraction of polar pesticides.…”

“…The selected pesticides can be divided into three groups based on their polarity: low polar pesticides, log P ˃ 2 (LIN and TEB with log P of 3.12 and 4.38), moderately polar, 2 ˃ log P ˃ 1 (DIM with log P of 1.37) and polar pesticides, log P < 1 (IMI and ACE with log P of 0.56 and 0.8). They all exist in uncharged form over a wide pH range (2-9), since they are either very week acids or very week bases [21]. The composition of organic phase was found to significantly affect the removal efficiency of pesticides from the aqueous phase [21].…”

Recent Advances in the Extraction of Triazines from Water Samples

“…The system was coupled to high performance liquid chromatography-mass spectrometry (HPLC-MS) as separation and detection technique. Under these conditions LODs from 0.061 to 0.26 were obtained for triazine compounds [8].…”

A simple method for simultaneous determination of nine triazines in drinking water

“…So solid-phase microextraction (SPME) (34), stir bar sorptive extraction (SBSE) (35)(36)(37), micro-liquidliquid extraction (micro-LLE) (38), liquid-phase microextraction (LPME), and liquid-liquid-solid microextraction (LLSME) (39)(40)(41), dispersive liquid-phase microextraction (DLPME) (42,43), and solid-phase membrane tip extraction (SPMTE) (44) have been developed for the extraction of triazines in water samples as alternative to the SPE techniques. These new techniques have some advantages over SPE, but they also have drawbacks because some of them have shown low sensitivity for the triazines studied (34,36,38,43,44), others are very laborious (38)(39)(40)(41), and in many cases, poor recoveries were obtained (36,42,43). Triazine herbicides have been analyzed using chromatographic techniques (gas chromatography (GC) and high-performance liquid chromatography (HPLC)).…”

“…Triazine herbicides have been analyzed using chromatographic techniques (gas chromatography (GC) and high-performance liquid chromatography (HPLC)). In the studies employing HPLC for the determination of triazines, various detectors have been used as diode array detection (DAD) (6-8, 14, 15, 18, 20, 22, 24, 25, 36, 43), ultraviolet detection (UV) (19,23,28,38,41,42,44), or mass spectrometry (MS) detection (9,10,12,13,16,21,27,30,33,40). It is important to note the advantages relating to the cost when using detection by DAD or ultraviolet (UV) compared to techniques that use MS as detector.…”