Marchei Emilia, Pellegrini Manuela, Pacifici Roberta, Palmi Ilaria, Pichini Simona
Drug Research and Evaluation Department, Istituto Superiore di Sanitá, V.le Regina Elena 299, 00161 Rome, Italy.
J Pharm Biomed Anal. 2005 Mar 9;37(3):499-507. doi: 10.1016/j.jpba.2004.11.013. Epub 2004 Dec 15.
A procedure based on liquid chromatography-mass spectrometry (LC-MS) is described for determination of caffeine, theobromine, theophylline, taurine in different dietary supplements. After addition of tryptophan as internal standard, both solid and liquid specimens were extracted with 4 ml of hexane/isopropanol (9:1). Chromatography was performed on a C18 reversed-phase column using water/methanol/acetic acid (75:20:5, v/v/v) as a mobile phase. Analytes were determined in LC-MS single ion monitoring mode with atmospheric pressure ionization-electrospray (ESI) interface. The method was validated in the range 0.1-500 and 0.06-500 microg/ml or microg/g for taurine and caffeine, respectively; 0.06-100 microg/ml or microg/g for theobromine and theophylline. Mean recoveries ranged between 70.1 and 94.4% for different analytes. The quantification limits were 0.1 microg/ml or microg/g for taurine and 0.06 microg/ml or microg/g for methylxanthines either in liquid samples or in solid samples. The method was applied to the analysis of various dietary supplements containing methylxanthines and taurine. Energetic drinks contained amounts of taurine in the range of hundreds to thousands microg/ml and ten times lower amounts of caffeine. Conversely, herbal powders, tablets and capsules mainly contained mg amounts of caffeine per gram of product with the other two methylxanthines in the range of ten to hundred microg/g.
描述了一种基于液相色谱 - 质谱联用（LC - MS）的方法，用于测定不同膳食补充剂中的咖啡因、可可碱、茶碱和牛磺酸。加入色氨酸作为内标后，用4 ml己烷/异丙醇（9:1）对固体和液体样品进行萃取。在C18反相柱上进行色谱分析，以水/甲醇/乙酸（75:20:5，v/v/v）作为流动相。采用大气压电离 - 电喷雾（ESI）接口，在LC - MS单离子监测模式下测定分析物。该方法在0.1 - 500 μg/ml和0.06 - 500 μg/ml或μg/g范围内分别对牛磺酸和咖啡因进行了验证；可可碱和茶碱的验证范围为0.06 - 100 μg/ml或μg/g。不同分析物的平均回收率在70.1%至94.4%之间。液体样品或固体样品中牛磺酸的定量限为0.1 μg/ml或μg/g，甲基黄嘌呤的定量限为0.06 μg/ml或μg/g。该方法应用于分析各种含甲基黄嘌呤和牛磺酸的膳食补充剂。能量饮料中牛磺酸的含量在数百至数千μg/ml范围内，咖啡因含量则低十倍。相反，草药粉、片剂和胶囊每克产品中主要含有毫克量的咖啡因，另外两种甲基黄嘌呤的含量在10至100 μg/g范围内。
