Abstract:

A simple and rapid method using high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) was developed for the simultaneous determination of phenolphthalein and sibutramine illegally added to weigh loss functional foods. Along with this, mass spectral fragmentation pathways of the above analytes were elucidated. In the method, various samples, including weight loss coffee, tea, capsule and albumin as well as apple vinegar chewing tablets were extracted for 15 minutes using methanol with the assistance of ultrasonic. Qualitative and quantitative analysis was carried out for 20 samples in the MRM mode following chromatographic separation on a Waters Atlantis T3 (150 mm × 2.1 mm, 3μm) column. Linear ranges for phenolphthalein and sibutramine detected by the method were 2.5 － 500μg/L and 0.15 － 500μg/L, and corresponding correlation coefficients 0.9992 and 0.9996, respectively. Mean recoveries for both analytes in aforementioned 5 types of weight loss functional foods at three spike levels (low, medium and high) were within the range of 82.3%－103.6% (n = 6), with intraday precision RSDs less than 5% and inter-day precision RSDs less than 8%. Sibutramine was detected in 13 of 20 samples, and namely the detection ratio was 65%. Phenolphthalein was detected in 9 of 20 samples and namely the detection ratio was 45%. This method is characterized by rapidity, high sensitivity and recovery, and good reliability, thereby providing a robust approach for the determination of phenolphthalein and sibutramine illegally added to weight loss functional foods.

Key words: weight loss functional food, high performance liquid chromatography tandem mass spectrometry (HPLC-MS/ MS), phenolphthalein, sibutramine, mass spectral fragmentation pathway