Combination of dispersive solid phase extraction with dispersive liquid–liquid microextraction for the determination of multi-residue pesticides from mango; Application of simplex centroid design in optimisation of the extractant composition

Abstract

ABSTRACT A mixed mode dispersive solid phase extraction was introduced for the extraction of multi – class pesticides in mango samples. In the following, the extracted analytes were more concentrated by dispersive liquid – liquid microextraction. By the use of advantages of both sample preparation methods, the proposed analytical method was sensitive with high enrichment factors and less matrix effect. Some biopolymers including chitosan, agarose, and cellulose were employed as the sorbent in dispersive solid phase extraction due to their compatibility with the trends of green chemistry. The best composition of the biopolymers was obtained by a simplex centroid design and the data illustrated that the weight ratio of 4:1:1 (w/w/w) was the best composition of chitosan: agarose: cellulose for extraction of the pesticides, respectively. After optimisation of effective factors, the figures of merit were calculated. The validation data showed that the limit of detection were from 0.13 to 0.32 ng g−1. All of the calibration curves were linear in the range of 1.07–1000 ng g−1. The introduced method was successfully utilised for the extraction of the pesticides in mango samples. Fortunately, all studied samples were free of the analytes.