Determination of Three Capsaicinoids in Raw Red Pepers and Seasoning Powders by Liquid Chromatography with Coulometric Detection

The simultaneous determination of three capsaicinoids in raw red pepper and in foods was studied by liquid chromatography coupled to a coulometric detector. The capsaicinoids were separated on an ODS C18 reversed column by isocratic elution with a mobile phase based on acetonitrile −0.15 M acetic acid (51:49%, v/v) at a flow rate of 0.8 mL min −1 . The limit of detection (S/N> 3) was 10 pg (injected mass) at an applied potential of 0.650 V vs. Pd. The peak area of the three studied compounds was found to be related to the amount injected from 50 pg to 100 ng range (r=0.999). The relative standard deviation (RSD, n=10) was comprised between 1.5∼4.4 and 1.0∼3.5 % for 100 pg and 5 ng, respectively. The determination of three capsaicinoids in raw red peppers and red pepper containing foods was successfully realized.