Development of a liquid chromatography tandem mass spectrometry method for simultaneous determination of eight adulterants in slimming functional foods.

A method for simultaneous determination of eight adulterants including two appetite suppressants, two energy expenditure-enhancing drugs, one diuretic and three cathartics in slimming functional foods by high performance liquid chromatography with electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS) was established. After samples were ultrasonically extracted with 70% (v/v) methanol aqueous solution and centrifuged, the components of ephedrine, norpseudoephedrine, fenfluramine, sibutramine, clopamide, emodin, rhein, and chrysophanol in sample solution were separated by a Hypersil Gold column (2.1 mm × 150 mm, 5 µm) using a programmed gradient elution. A mobile phase consisting of 0.02% (v/v) formic acid-ammonium formate buffer solution (pH=3.50) and methanol was used for elution with a flow rate set at 250 µL/min and column temperature of 25 °C. Qualitative determination was based on characteristic ion pairs and retention time of the targeted compounds using SRM (selective reaction monitoring) mode. Clenbuterol and ibuprofen were internal standards in positive and negative ionization mode, respectively. The internal standard curves were used for quantification measurement. The average recoveries of three different concentrations were from 80.2% to 94.5%. The limits of detection (LODs) were from 0.03 to 0.66 mg/kg (except chrysophanol 1.6 mg/kg). The linear dynamic range covered from 1 to 500 µg/L (except chrysophanol 50-5000 µg/L) for the twelve samples analyzed. Adulterants in four different kinds of slimming functional foods were determined by this developed method, and satisfactory results were obtained. These experimental results showed that, adulteration of sibutramine or/and fenfluramine were the major adulterating components with contents varying from 6.1 to 1.3×10(3) mg/kg and 1.9 to 9.7×10(3) mg/kg, respectively. In addition, three cathartic compounds were detected in six of those tested samples, and ephedrine, norpseudoephedrine and clopamide were not detected in all samples.

[Simultaneous determination of five illegal drugs in weight control foods with solid phase extraction-high performance liquid chromatography].

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.

Simultaneous determination of clopamide-pindolol combination in tablets by zero-crossing derivative spectrophotometry.

A first-derivative spectrophotometric method, using a 'zero-crossing' technique of measurement has been used for determining clopamide-pindolol mixture in tablets. In the first-derivative mode the zero-crossing points of clopamide and pindolol occur at 272.6 and 262.4 nm, respectively. The relative ease offered by this technique for the quantification of these drugs with closely overlapping bands was demonstrated. The linearity of the calibration curves was satisfactory (r = 0.9998) and the precision (RSD%) better than 1.89. Detection limits were 0.50 and 0.44 micrograms ml-1 for pindolol and clopamide, respectively. No spectral interferences from tablet excipients were found. Applications are given for the assay of commercial tablets and content uniformity test. The procedures proved to be suitable for rapid and reliable quality control.