Development of microwave radiations-induced homogeneous liquid-liquid microextraction method for extraction of pyrethroid pesticides in fruit and vegetable samples

ABSTRACT

A rapid, efficient and reliable microwave-assisted homogenous liquid–liquid microextraction method has been developed for the extraction of pyrethroid pesticides from fresh fruit and vegetable samples prior to their determination by gas chromatography–mass spectrometry. For this purpose, first, the samples are crushed and the obtained juices are separated and transferred into a glass test tube. Then, a mixture of methanol and deionised water is used to extract the analyte residues in refuse of the samples. The supernatant phase is removed and mixed with the related juice obtained from the previous step. After that, the solution temperature is adjusted at −10°C and a few microlitres of chloroform is dissolved in it. Then, it is exposed to microwave irradiations to break down the homogenous phase. In this step, a cloudy state is produced and the tiny droplets of chloroform containing the extracted analytes are sedimented at the bottom of the tube. A portion of the sedimented phase is removed and injected into the separation system. Validation of the method showed that limits of detection and quantification were in the ranges of 4.3–9.4 and 14.4–30.5 ng kg⁻¹, respectively. Enrichment factors and extraction recoveries of the selected analytes ranged from 315 to 415% and 63–83%, respectively. The method had a proper precision with relative standard deviations less than ≤7.7% for intra-(n = 6) and inter-day (n = 6) precisions at a concentration of 75 ng kg⁻¹ of each analyte. Finally, the method was used for determination of the analytes in fresh fruit and vegetable samples in a predetermined times.

KEYWORDS:

• Microwave-assisted homogenous liquid–liquid microextraction
• pyrethroid pesticides
• gas chromatography
• mass spectrometry
• fruit
• vegetable

Disclosure statement

No potential conflict of interest was reported by the author(s).