Rapid Screeninga nd Quantification of Capsaicin, Dihydrocapsaicin, Nonivamide in Edible Oil by Ultra-high Performance Liquid Chromatography-quadrupole/orbitrap Mass Spectroscopy

A method was developed for rapid screening of and quantification capsaicin, nonivamide and dihydrocapsaicin in edible oil using ultra-high performance liquid chromatography-quadrupole/orbitrap mass spectrometry (UHPLC-Q/Orbitrap). Samples were dissolved in dichloromethane, and then extracted with sodium hydroxide solution and acidified with sulfuric acid. The extract was cleaned up on a Prime HLB solid phase extraction (SPE) column and separated by UHPLC on Thermo Scientific Accucore Vanquish C₁₈+ (100 mm×2.1 mm, 1.5 μm) column. The mobile phase was acetonitrile containing 0.1% formic acid and water containing 0.1% formic acid with gradient elution. Data were collected by Q/Orbitrap MS. The results showed that good linearity was observed in the concentration range from 0.1 to 40 μg/L for all 3 capsaicinoid, with absolute coefficients (R²) greater than 0.999. The average recoveries were in the range from 66.7% to 112.8% at 3 spiked levels with relative standards deviation (RSDs) between 3.2% and 9.7%. The limits of detection (LODs) ranged from 0.02 to 0.05 μg/kg and limit of quantitation between 0.1 to 0.2 μg/kg. The method can quickly screen and confirm three capsaicins in edible oils without reference materials, and can also accurately quantify with reference materials, providing new technologies and ideas for screening confirmation and accurate quantification of illegally added recycled fats in edible oils.