Validation of the method for determination of Phenolphthalein and Sibutramine in weight‐loss functional foods from Viet Nam by UPLC‐MS/MS

Abstract

A rapid, selective, and sensitive method by using ultra‐performance liquid chromatography‐tandem mass spectrometry (UPLC‐MS/MS) for the simultaneous determination of phenolphthalein (PP) and sibutramine (SB) in weight‐loss functional foods was developed. The optimal conditions of liquid chromatographic separation and mass spectroscopy of PP and SB have also been examined. The linear ranges for both PP and SB detected by the method were 0.20÷10.0 ng/mL, and corresponding correlation coefficients of 0.9991 and 0.9992, respectively. Mean recoveries of both analytes in the weight‐loss functional foods at three spike levels (low, medium, and high) were within the range of 98.5÷102.5 % (n = 11). LOD, LOQ values of PP were 0.12 and 0.36 ng/mL, respectively, while SB's LOD and LOQ were 0.09 ng/mL and 0.28 ng/mL. The impact of the matrix effect on the accuracy, repeatability, and recovery of the process was negligible. The recommended approach was applied to determine the content of the two substances in ten weight‐loss drug capsules and nine weight‐loss herbal teas, which were purchased in Ho Chi Minh City Viet Nam in 2019. PP was found in 5 of 19 samples, and SB was detected in 6 of 19 samples.