Abstract:A QuECHERS-liquid chromatography tandem mass spectrometry method for the detection of capsaicin and dihydrocapsaicin in fresh chilis was established. The pretreatment conditions of QuECHERS were optimized， and the capsaicin and dihydrocapsaicin in fresh chilis were extracted. 0.1% acetonitrile formate and 0.1% formic acid aqueous solution were used as mobile phases for detection and analysis by a combination of multiple reaction monitoring（MRM）， information dependent acquisition （IDA）， and enhanced product ion scanning （EPI）. The secondary library of standard EPI of capsaicin and dihydrocapsaicin was established，and the target compounds were accurately qualitatively and quantitatively detected by combining retention time， ion abundance ratio， and library alignment. The results showed that capsaicin and dihydrocapsaicin were linear in the range of 1.5-500.0 ng/mL （correlation coefficient R2 = 0.999）， and the limits of quantification of capsaicin and dihydrocapsaicin were 0.087 mg/kg and 0.069 mg/kg； the recovery rate was 72.0%-110.3%， and the relative standard deviation was within 8.0%. The detection method was featuring short detection time and high sensitivity. The false positive could be effectively excluded， and the detection range was wide. The capsaicin and dihydrocapsaicin in chilis with different pungency degrees could be detected and analyzed.