Development of a new ion-pairing dispersive liquid-liquid microextraction for determination of some acidic pesticides

A simple, efficient, and sensitive microextraction procedure named ion-paring deep eutectic solvent based dispersive liquid-liquid microextraction was developed and used for determination of three acidic herbicides including fenoxaprop, fluazifop, haloxyfop from edible oil samples. For this purpose, firstly, a three component deep eutectic solvent composed of phosphocholine chloride, dichloroacetic acid, and decanoic acid was prepared under mild condition and it was used in microextraction process. Firstly, the analytes were extracted into sodium hydroxide solution by deprotonation of the analytes. Afterward, deprotonation pesticides were extracted into phosphocholine chloride: dichloroacetic acid: decanoic acid with the aid of tri-butyl amine (ion-pair agent) in the presence of acetic acid (as a pH adjustment agent). The validation parameters indicated that the method has low limits of detection and quantification in the range 0.09 to 0.71 and 0.3 to 2.3 ng mL–1, respectively. Relative standard deviations of the method were obtained in the range of 4.8–6.9% and 7.9–9.0% for intra– (n=6) and inter–day (n=5) precisions, respectively. High enrichment factors ranging from 566 to 626 and extraction recoveries ranging from 85 to 94% were the other advantages of the method. These merits showed that the method is an efficient, inexpensive and successful procedure in the determination of the analytes. The method was successfully performed on determination of 35 edible oil samples and haloxyfop was found in three corn oil samples.

Keywords:

Dispersive liquid–liquid microextraction , Acidic pesticides , High performance liquid chromatography