Ultrasound-assisted Emulsification Microextraction Method Based on Applying Low Density Organic Solvents as a Sensitive and Efficient Sample Preparation Method for Determination of Abamectin in Fruit Juice Samples

The analytical use of ultrasound-generated emulsations has recently found a growing interest to improve efficiency in liquid-liquid microextraction since they increase the mass transfer between the two immiscible phases implied and leads to emulsification. Thus, dispersed droplets can act as efficient liquid-liquid microextraction in continuous phase, and later they can be readily separated by centrifugation. Ultrasound-assisted emulsification microextraction (USAEME) based on applying a low density organic solvent and high-performance liquid chromatography (HPLC)-UV detection was presented for extraction and determination of abamectin in fruit juice samples. Toluene as extraction solvent at microliter volume level was injected slowly into a home-designed centrifuge glass vial that was located inside the ultrasonic water bath. The main advantages of method are high preconcentration factor, high recovery, good repeatability and extraction solvent volume at µL level. The influence of several variables (e.g. type and volume of extraction solvent, ionic strength and extraction temperature, etc.) on the performance of the sample preparation step was carefully evaluated. Under the optimum conditions, the enrichment factors 261 and 217 were obtained for avermectin (B1b) and avermectin (B1a), respectively, and calibration graphs were linear in the range of 5.0-500 µg L-1 and 2.0-500 µg L-1 with detection limits of 1.5 µg L-1 and 0.6 µg L-1 for B1b and B1a, respectively, in fruit juice samples. The relative recoveries of abamectin in fruit juice samples at spiking level of 5.0 µg L-1 are in the range of 90% to 94%. USAEME combined with HPLC-UV is a fast, simple and efficient method for the determination of abamectin in fruit juice samples.