Rapid Method for the Determination of Capsaicin and Dihydrocapsaicin in Gochujang Using Ultra-High-Performance Liquid Chromatography

Abstract

A sensitive and specific heating block method coupled with ultra-HPLC (u-HPLC) was developed for the analysis of capsaicin in Gochujang and validated by comparing with a conventional HPLC (AOAC Method 995.03). The method validation parameters yielded good results, including linearity, precision, accuracy, and recovery. The u-HPLC separation was performed on a reversed C₁₈ column (50 2 mm id, particle size 2 m), followed by fluorescence detection (excitation 280 nm, emission 325 nm). Methanol was used as the extracting solvent, and the amount of sample taken was approximately 0.2 g; the optimum amount of extraction solvent and extraction time were 15 mL and 1 h, respectively. The recovery of capsaicin in Gochujang was more than 93, and the LOD and LOQ of the u-HPLC analysis were 0.05 and 0.16 g/g for capsaicin and 0.05 and 0.16 g/g for dihydrocapsaicin. The calibration graphs for capsaicin and dihydrocapsaicin were linear from 0.2 to 10.0 g/mL for u-HPLC. The interday and intraday precisions (RSD values) were <6.27.