Analysis of synephrine in da-cheng-qi decoction by HPLC employing precolumn derivatization with 9-fluorenylmethyl chloroformate.

A sensitive and reliable method has been developed to determine synephrine in a famous purgative Chinese medicinal prescription, da-cheng-qi decoction. After purified by solid-phase extraction (SPE), the decoction was derivatized with 9-fluorenylmethyl chloroformate in borate buffer and analyzed by reversed-phase high-performance liquid chromatography equipped with a diode-array detector. The chromatographic separation was carried out on a Shimadzu shim-pack VP-ODS column using acetonitrile-water as mobile phase. This method was validated in terms of linearity, recovery, precision, accuracy, and repeatability. Calibration curves were linear (r(2) > 0.99) over the concentration range of 0.78-100 microg/mL, and the mean recovery was 93.28%. The intra- and inter-batch precisions were less than 2% in terms of relative standard deviations. The accuracy and repeatability were well within the acceptable range. The limit of detection was 0.25 microg/mL. This validated method also can be used for assays of herbal products, fruits, dietary supplements, and biological samples containing synephrine.