Liu Hongcheng, Shao Jinliang, Li Qiwan, Li Yangang, Yan Hong Mei, He Lizhong
Supervision and Testing Center for Farm Product Quality, Ministry of Agriculture (Kunming), Institute of Quality Standard and Testing Technology, Yunnan Academy of Agriculture Science, 650223, Kunming, People's Republic of China.
J AOAC Int. 2012 Jul-Aug;95(4):1138-41. doi: 10.5740/jaoacint.11-275.
A simple, rapid method was developed for simultaneous extraction of trigonelline, nicotinic acid, and caffeine from coffee, and separation by two chromatographic columns in series. The trigonelline, nicotinic acid, and caffeine were extracted with microwave-assisted extraction (MAE). The optimal conditions selected were 3 min, 200 psi, and 120 degrees C. The chromatographic separation was performed with two columns in series, polyaromatic hydrocarbon C18 (250 x 4.6 mm id, 5 microm particle size) and Bondapak NH2 (300 x 3.9 mm id, 5 microm particle size). Isocratic elution was with 0.02 M phosphoric acid-methanol (70 + 30, v/v) mobile phase at a flow rate of 0.8 mL/min. Good recoveries and RSD values were found for all analytes in the matrix. The LOD of the three compounds was 0.02 mg/L, and the LOQ was 0.005% in the matrix. The concentrations of trigonelline, nicotinic acid, and caffeine in instant coffee, roasted coffee, and raw coffee (Yunnan Arabica coffee) were assessed by MAE and hot water extraction; the correlation coefficients between concentrations of the three compounds obtained were close to 1.
开发了一种简单、快速的方法，用于同时从咖啡中提取葫芦巴碱、烟酸和咖啡因，并通过串联的两个色谱柱进行分离。采用微波辅助萃取（MAE）法提取葫芦巴碱、烟酸和咖啡因。选择的最佳条件为3分钟、200磅力/平方英寸和120摄氏度。色谱分离采用串联的两个色谱柱，即聚芳烃C18柱（内径250×4.6mm，粒径5μm）和氨基键合硅胶柱（内径300×3.9mm，粒径5μm）。等度洗脱采用0.02M磷酸-甲醇（70 + 30，v/v）流动相，流速为0.8mL/min。在基质中所有分析物均具有良好的回收率和相对标准偏差值。三种化合物的检测限为0.02mg/L，定量限在基质中为0.005%。通过微波辅助萃取和热水萃取法评估了速溶咖啡、烘焙咖啡和生咖啡（云南小粒咖啡）中葫芦巴碱、烟酸和咖啡因的含量；所获得的三种化合物浓度之间的相关系数接近1。
