Department of Analytical Chemistry and Computer Chemistry, University of Plovdiv Paisii Hilendarski, 24 Tzar Asen Str., 4000, Plovdiv, Bulgaria.
Department of Analytical Chemistry, Nutrition and Food Sciences, University Institute of Materials, Faculty of Science, University of Alicante, P.O. Box 99, 03080, Alicante, Spain.
Talanta. 2025 Jan 1;282:126967. doi: 10.1016/j.talanta.2024.126967. Epub 2024 Sep 26.
The current research aims to develop a new analytical method applying a dispersive liquid-liquid microextraction (DLLME) assisted by vortex and using an environmentally friendly extractant for the preconcentration of organochlorine and organophosphorus pesticides followed by gas chromatography-tandem mass spectrometry (GC-MS/MS) analysis. The extractant (i.e., natural deep eutectic solvent (NADES)) is safe, cheap, biodegradable and can be prepared by simply mixing DL-menthol and decanoic acid (molar ratio 2:1). The main experimental factors affecting the extraction of all analytes evaluated (19 organochlorine and organophosphorus pesticides) have been optimised using a multivariate analysis consisting in two steps: a Plackett-Burman design followed by a central composite design (CCD). Seven experimental factors have been evaluated: (i) sample volume; (ii) NADES volume; (iii) sample pH; (iv) extraction time; (v) centrifugation time; (vi) centrifugation speed; and (vii) ionic strength (NaCl %, w v). For the significant variables, the optimum values were 10 mL sample and 45 μL NADES. No pH adjustment as well as addition of NaCl were needed. The other variables were set at 3 min extraction time, 5 min centrifugation time and 900×g centrifugation speed, respectively. Under the optimised extraction conditions, the limit of quantification (LOQ) values ranged between 0.2 and 78 ng L for all analysed pesticides. Furthermore, the proposed analytical method has been successfully applied to drinking water (bottled spring water). The recovery study (n = 3) has been evaluated at 0.1, 1.0 and 5.0 μg L spiking levels, obtaining relative recovery values within the range of 70 % and 117 % and RSD values between 1 % and 20 % for all the analytes studied, except for p,p-DDT (56-77 % in high conductivity water samples).
本研究旨在开发一种新的分析方法，应用分散液液微萃取（DLLME）辅助涡旋，并使用环保萃取剂对有机氯和有机磷农药进行预浓缩，然后进行气相色谱-串联质谱（GC-MS/MS）分析。萃取剂（即天然深共晶溶剂（NADES））安全、廉价、可生物降解，可通过简单混合 DL-薄荷醇和癸酸（摩尔比 2:1）制备。使用两步法的多元分析（Plackett-Burman 设计 followed by a central composite design (CCD)）优化了所有分析物（19 种有机氯和有机磷农药）萃取的主要实验因素。评估了七种实验因素：（i）样品体积；（ii）NADES 体积；（iii）样品 pH；（iv）萃取时间；（v）离心时间；（vi）离心速度；和（vii）离子强度（NaCl%，w/v）。对于显著变量，最佳值为 10 mL 样品和 45 μL NADES。无需调整 pH 值以及添加 NaCl。其他变量分别设定为 3 分钟萃取时间、5 分钟离心时间和 900×g 离心速度。在优化的萃取条件下，所有分析农药的定量限（LOQ）值在 0.2 和 78 ng/L 之间。此外，该分析方法已成功应用于饮用水（瓶装矿泉水）。回收率研究（n=3）在 0.1、1.0 和 5.0 μg/L 加标水平下进行评估，除了对 p,p-DDT（高电导率水样中为 56-77%）外，所有研究分析物的相对回收率值在 70%和 117%之间，RSD 值在 1%和 20%之间。
