HPLC Determination of 6 Dihydropyridine Chemicals in Healthy Products for Anti-Hypertension

HPLC was applied to the simultaneous determination of 6 dihydropyridine chemicals, which were added illegally in healthy products for anti-hypertension. The 6 compounds in samples were extracted ultrasonically with methanol. The extracted solution was separated on an ACE C18 (250 mm×4.6 mm, 5 μm) chromatographic column with the column temperature of 35 ℃. A mixture of 0.2% (φ) phosphoric acid solution and acetonitrile was used as mobile phase for gradient elution with the flow rate of 1.0 mL·min-1. The 6 compounds were detected with DAD at the wavelength of 235 nm. Quantification analysis was performed by the external standard method. Linear relationships were found between the peak areas and the mass concentrations of the 6 compounds in definite ranges, with detection limits (3S/N) of 56 mg·kg-1 and the low limits of determination (10S/N) of 167 mg·kg-1. Recovery rates obtained by standard addition method were in the range of 96.0%-101% and RSDs (n=6) were in the range of 1.0%-1.2%. The positive samples were further verified by LC-MS/MS.