Rapid quantification of five major capsaicinoids in Zunyi chili peppers (Capsicum Annuum L.) using ultra-high performance liquid chromatography with fluorescence detection

A rapid UPLC-FLR method was developed for simultaneous quantification of five major capsaicinoids in chili peppers. Separation of nordihydrocapsaicin, capsaicin, dihydrocapsaicin, homocapsaicin II, and homodihydrocapsaicin I was achieved within 5 min using a Waters HSS T3 column with optimized QuEChERS preparation. The method showed good linearity (r ≥ 0.9902), with LODs of 0.10-0.28 mg/kg, LOQs of 0.35-0.92 mg/kg, and recoveries of 64.5-118.4% (RSD ≤ 10%). Applied to nine Zunyi chili samples from seven varieties, total capsaicinoid content ranged from 11.05 to 4532.50 mg/kg dry weight, revealing substantial differences among varieties and geographical origins. This method is suitable for rapid and accurate analysis of multiple capsaicinoids in chili peppers and related products.