Abstract:A new method for the determination of chitin in health foods using high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) was established. After hydrolysis with hydrochloric acid, chitin in health food samples is transformed into glucosamine. The supernatant was passed through an OASIS MCX solid phase extraction (SPE) column, followed by washing with water; the eluent was discarded. Prior to elution with 5% ammonia/methanol, the column was drained using a vacuum pump. The eluent was dried under nitrogen at 60 ℃ in a water bath, and then dissolved in the initial mobile phase. The separation was performed on a C18 column using acetonitrile and 0.1% formic acid aqueous solutions as the mobile phase for gradient elution. Tandem mass spectral acquisition was conducted in the negative electrospray ionization mode using multiple reaction monitoring (MRM). The hydrolysis, purification, and reaction conditions were investigated and optimized. The results indicated that under the optimized conditions, the chitin hydrolyzate had a good linear relationship with concentration in the range of 0.1~50 mg/L, with a correlation coefficient of 0.9907. The limit of determination (LOD) of Chitin was 1.5 μg/g (S/N = 3), limit of quantification (LOQ) was 6.25 μg/g (S/N = 10). The mean spiked recovery rate of the samples was 89.2%~92.4% with a relative standard deviation of 0.25%~1.35% (n = 6). The method established was demonstrated to have simple pre-treatment and high selectivity, recovery rate, and accuracy, showing its suitability for the determination of chitin in health foods.
