A new solidified effervescent tablet-assisted dispersive liquid–liquid microextraction for the analysis of fungicides in fruit juice samples

Abstract

A simple and rapid pretreatment method based on effervescent tablet-assisted dispersive liquid–liquid microextraction was introduced for the determination of three fungicides (azoxystrobin, chlorothalonil, and cyprodinil) in fruit juice samples followed by liquid chromatography-ultraviolet detection. The effervescent tablet composed of sodium dihydrogen phosphate, sodium carbonate and 1-dodecanol was prepared in a simple way. The ingredients consisting of the above three components were manually blended in an empty medicine strip and cooled in a refrigerator. Hence, an effervescent tablet was obtained within 5 min without the need for a press machine thanks to the solidification of 1-dodecanol at room temperature. In situ generation of carbon dioxide during the microextraction process enabled the dispersion of the extractant within the aqueous phase and enhanced the contact area both between phases. Under the optimized conditions, the extraction recoveries ranged from 53 to 88%. Good linearity was observed by the square of correlation coefficients better than 0.9980. Relative standard deviations were less than 4.8% for intra-day and 7.6% for inter-day precision at a concentration of 3.0 μg L⁻¹ of each analyte. Limits of detection ranged from 0.09 (chlorothalonil) to 0.19 μg L⁻¹ (azoxystrobin). The proposed new method was successfully applied for the analysis of three fungicides in real samples of fruit juices and satisfactory recoveries (76–104%) were achieved.