Using safranin T as a charge transfer-sensitive ion-pairing reagent in ultrasound-assisted cloud point extraction: Determination of bisphenol a in selected beverages

Abstract

In this study, a new ultrasonic-assisted cloud point extraction method coupled with spectrophotometry was developed to extract from and determine bisphenol A (BPA) in a sample matrix. The method is based on charge transfer-sensitive ion-pairing complex formation between BPA and Safranin T in the presence of nitrate in a micellar interface at pH 5.0. The variables affecting extraction efficiency were optimized. A good linear relationship with a significant sensitivity difference was obtained in the ranges of 2-40 and 2-120 µg/L with LODs of 0.54 and 0.38 µg/L after preconcentration with two different extractants, respectively. From a preconcentration of a 15 mL sample, a preconcentration factor of 60 was obtained. Due to the lack of a certified material compatible with the sample matrix, the method was validated by conducting intraday and interday accuracy and precision studies based on two spiked QC samples (with a recovery rate greater than 94% and an RSD ranging from 3.8 to 5.9%). Moreover, the beverage samples were analyzed by the standard addition method to control for possible matrix effects. BPA was detected in the range of 1.8-7.2 µg/L in beverages with Triton X-114, whereas the levels changed to a range of 1.8-7.3 µg/L with Triton X-45. In such a way not to create a threat, these levels were considerably lower than the specific migration limit set by the European Union.