Comparison of Soxhlet and Microwave-Assisted Extractions for the Determination of Fenitrothion Residues in Beans

Abstract

White and black "niebe" beans [Vigna unguiculata (L.) Walp] from Senegal were treated with fenitrothion (O,O-dimethyl O-4-nitro-m-tolyl phosphorothioate), and the residues were determined by high-performance liquid chromatography (HPLC) and electron capture gas chromatography (EC-GC). Fenitrothion residues from the beans were extracted by Soxhlet extraction (SE) and microwave-assisted extraction (MAE). A column cleanup procedure was used to remove the coextractives in the extract before HPLC and EC-GC analyses. The overall mean recoveries of fenitrothion residues in the 0.19-1.90 microg/kg fortification range determined from extracts obtained by SE and MAE were 88.4 and 89.8%, respectively, with respective relative standard deviations of <4%. The results show that MAE is a viable alternative to the commonly used SE for the determination of fenitrothion residues in beans.

Determination of alachlor, metolachlor, and their acidic metabolites in soils by microwave‐assisted extraction (MAE) combined with solid phase extraction (SPE) coupled with GC‐MS and HPLC‐UV analysis

“…Among the parameters used in MAE, magnetron power was arbitrarily set to 100% (1000 W) for a full oven (12 vessels); also, a sample weight of 10 l 0.1 g was selected since this is the amount required in residue methods based on the instrumental analytical systems applied in this study in order to obtain low LOQ values [16,17].…”

“…Ever since the first use of MAE techniques for the extraction of organic pollutants [10], there has been an increasing interest in them because of their (i) simplicity, (ii) time efficiency as they allow for the simultaneous extraction of numerous samples, (iii) low organic solvent consumption [11], (iv) ability to handle samples under strictly controlled temperature and pressure conditions, and (v) comparable accuracy to supercritical fluid extraction and sonication and their superiority in terms of precision [12,13]. Concerning the pesticide residue analysis, MAE has been used for the extraction of organochloride [14], pyrethroid [15], and organophosphoric insecticides [16], for herbicides like triazines, phenoxyalcanoic acids [17,18] and chloroacetanilides [17], and fungicides [19], in different kinds of matrices like soil, sediments, fruits, vegetables, tobacco, and water.…”

Modern Extraction Techniques for Pesticide Residues Determination in Plant and Soil Samples

“…In 1997, Pylypiw et al used a MAE for determination of several pesticides in beet, cucumber, lettuce, pepper and tomato. The results show that MAE is a viable alternative for determination of atrazine and OPPs in orange peel (Bouaid et al, 2000), carbendazim, diethofencarb, azoxystrobine, napropamide and bupirimate in strawberries (Falqui-cao et al, 2001), fenitrothion in beans (Diagne et al, 2002) and pyrethroids in strawberries (Sanusi et al, 2004). Application of MAE for extraction of acetamiprid from cabbage (Pritam & Mukherjee, 2010) Wang et al, 2007).…”

Sample Preparation in the Analysis of Pesticides Residue in Food by Chromatographic Techniques

“…2000). The technique has proven to be better than soxhlet extraction by reducing the solvent consumption and extraction time (Diagne et al, 2002;Barriada-Pereira et al, 2003). Usually sample sizes range from 0.5 to 10 g and 10 ml of solvent is sufficient for the extraction time from less than 1 to 10 min.…”