A simple and rapid high performance liquid chromatography-evaporative light scattering detection (HPLC-ELSD) method was developed for simultaneous determination of phosphate anion and calcium cation in Plastrum testudinis. The analyte was separated on a Prevail C18 reserved-phase column (250mm×4.6mm, 5μm) using isocratic elution at a flow rate of 0.5mL/min. The column temperature was 25°C. The drift tube temperature and the nitrogen gas flow-rate of ELSD were set at 115°C and 2.5L/min, respectively. This developed method was able to determine phosphate anion and calcium cation with good linearity (r(2)>0.9997), precision (RSD<1.6%) and recovery (99.52-101.94%). The newly established method was successfully applied to evaluate the contents of phosphate anion and calcium cation in six commercial samples.
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