An environmentally friendly method based on micro-cloud point extraction for determination of trace amount of...

This study was conducted for quantitative determination of quercetin in food and fruit juice samples based on a green, fast, and accurate method namely, micro-cloud point extraction (MCPE). The proposed MCPE is essentially a miniaturized form of traditional cloud point extraction (CPE) in which only a few microliters of micellar extracting phase is sufficient for determination. Factors influencing the extraction efficiency, such as amount of Triton X-114 (5%, v/v), effect of pH, amount of Na₂SO₄ salt (5%, w/v) and time of centrifugation were investigated and optimized by experimental design. Under the optimized condition, the calibration range was found to be linear over 10-100 ng mL^-1 with the limit of detection of 2.2 ng mL^-1. The relative standard deviation of 2.8%, was obtained on a 30 ng mL^-1quercetin standard solution (n = 3). Finally, the proposed method was successfully applied for the determination of quercetin in onion, tomato, apple and orange juice samples.