Determination of Sibutramine and Phenolphthalein in Weight­loss Tea, Coffee, and Milk by Ultra-­Performance Liquid Chromatography Mass Spectrometry UPLC­-MS/MS

A rapid, simply and effective method using ultra­performance liquid chromatography coupled to mass spectrometry (MS) detection was developed in order to determine sibutramine and phenolphthalein in weight­loss tea, coffee, and milk. QuEChERS technique was used for cleaning­up sample matrices. The extracts were separated on C18 LC columns using the gradient elution of 0.1% formic acid in distilled water and acetonitrile. The recoveries at the concentration of 50 µg/kg were from 90.1 to 105.8% (with RSDR of 4.04 ­ 4.24%), from 91.9 to 100.2% (with RSDR of 3.20 ­ 4.71%), and from 86.5 to 100.5% (with RSDR of 5.17 ­ 5.49%) for weight­loss tea, coffee, and milk, respectively. Method quantitation limits were of 30 µg/kg.