本研究建立了保健品中甲壳素的高效液相色谱-串联质谱（HPLC-MS/MS）测定方法。含甲壳素保健品样品经盐酸水解后生成氨基葡萄糖，吸取上清液过OASIS MCX固相萃取小柱，用水淋洗固相萃取柱并弃去全部流出液，用真空泵抽干小柱，再用5%氨水甲醇洗脱被测物，洗脱液于60 ℃水浴中氮气吹干，用初始流动相定容，以C18色谱柱和乙腈-0.1%甲酸水流动相体系进行梯度洗脱分离，采用电喷雾负离子多反应监测（MRM）模式测定。实验考察优化了水解条件、净化条件和仪器条件。在优化实验条件下，甲壳素水解产物在0.1~50 mg/L浓度范围内线性关系良好，相关系数为0.9907；甲壳素的方法检出限（S/N=3）为1.5 μg/g，方法定量限（S/N=10）为6.25 μg/g；平均加标回收率为89.2%~92.4%，相对标准偏差（n=6）为0.25%~1.35%。该方法前处理简单、灵敏度高、选择性强、回收率高、精密度好，适用于保健品中甲壳素的测定。

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.

国家自然科学基金项目（51246006）；佛山市科技创新专项资金项目（2013AG100063）