Extraction and Preconcentration of Some Pesticides in Vegetable and Fruit Juice Samples Using SA@CaCO3 Sorbent Combined with Dispersive Liquid–Liquid Microextraction

Abstract

An efficient sample preparation method, dispersive solid-phase microextraction–dispersive liquid–liquid microextraction, coupled to gas chromatography–flame ionization detector was developed for the extraction, preconcentration, and determination of six pesticides (ametryn, penconazole, oxadiazon, diniconazole, tebuconazole, and fenoxaprop-P-ethyl) in vegetable and fruit juice samples. In this study, stearic acid–coated calcium carbonate is utilized as the sorbent. This sorbent is industrially available, and there is no need for a time-consuming synthesis procedure. The influence of several effective parameters on the extraction efficiency, including sorbent amount, salt addition, pH, adsorption and desorption time, type and volume of elution solvent, type and volume of extraction solvent, and time and speed of centrifugation, was assessed. The proposed procedure represented satisfactory values for the extraction recoveries and enrichment factors under optimal extraction conditions in the ranges of 52–93% and 260–465, respectively. Satisfactory precisions with relative standard deviation values of 1.74–4.96% (intra-day, n\u2009=\u20096) and 2.68–6.78% (inter-day, n =\u20094) were achieved at a concentration of 50 μg L−1 of each pesticide. Additionally, low limits of detection and quantification in the ranges of 0.20–0.85 and 0.67–2.83 μg L−1, respectively, were obtained. The procedure was applied to seven fruit and vegetable juice samples, and good relative recoveries between 82 and 103% were obtained.