Simultaneous determination of free capsorubin and capsanthin in red pepper powder using u-HPLC.

A simultaneous ultra-HPLC (u-HPLC) method for the determination of free capsorubin and capsanthin in red pepper powder was validated in terms of its precision, accuracy, and linearity. The u-HPLC separation was performed on an RP C18 column (particle size 2 μm, id 2 mm length 100 mm) and with a photodiode-array detector. The recoveries of capsorubin were greater than 83.8±1.7%; the LOD and LOQ of the u-HPLC analyses were 0.043 and 0.129 mg/kg, respectively. The intraday and interday precisions for capsorubin were less than 9.01%. The recoveries of capsanthin were greater than 87.7±1.5%, and the LOD and LOQ were 0.101 and 0.306 mg/kg, respectively. The intraday and interday precisions for capsanthin were less than 12.66%. All calibration curves for capsorubin and capsanthin exhibited good linearity (r 2 = 0.99) within the tested ranges.