Objective: To develop a method for simultaneous determination of hydrochlorothiazide, furosemide, clopamide, bumetanide and sibutramine hydrochloride in weight control foods with solid phase extraction-high performance liquid chromatography.
Methods: The analytes in the samples were extracted with 2% phosphoric acid-methanol (1:1, V/V) solution ultrasonically and centrifuged. The extracts were clean-up with Osis MCX SPE columns, concentrated under weak N2 stream, and reconstituted with 2% phosphoric acid-methanol (1:1, V/V) solution, vortex mixing and centrifugation at 12,000 r/min. The high performance liquid chromatography was performed with Phenomenex C18 (250 x 4.60 mm, 5 microm) as separation column, 0.02 mol/L acetonitrile potassium dihydrogen phosphate buffer as mobile phase, gradient elution of 1.0 mL/min for the flow rate, and 40 degrees C for the column temperature. The standard curve method was used for the quantitative analysis.
Results: A good linear range appeared for the five analytes from 0.25 to 100 microg/mL (r > or = 0.999). The detection limits were 5.2-108 microg/kg. The average recoveries were 86.5%-113.1%, with the relative standard deviations of 1.6%-8.9%.
Conclusion: The proposed method is a reliable method with high selectivity and high sensitivity for the detection of the five illegal chemicals in the weight control foods.