Hasegawa Takashi, Takahashi Kazunaga, Saijo Masaaki, Ishii Toshiyasu, Nagata Tomoko
Chiba Prefectural Institute of Public Health, Nitona-cho, Chuo-ku, Chiba-shi, Chiba, Japan.
Shokuhin Eiseigaku Zasshi. 2009 Dec;50(6):304-10. doi: 10.3358/shokueishi.50.304.
A rapid and simple method for determination of theophylline, theobromine and caffeine in dietary supplements containing guarana by ultra-performance liquid chromatography (UPLC) has been developed. Theophylline, theobromine and caffeine were extracted from finely powdered samples with water in a boiling water bath for 20 min, then the extracts were filtered and the filtrates were subjected to UPLC. Liquid samples were diluted with water and filteres, and the filtrates were subjected to UPLC. UPLC separation was performed on an AQUITY UPLC BEH C18 column (2.1 mm i.d.x50 mm, 1.7 microm, Waters) with 10 mmol/L ammonium acetate buffer (pH 4.0)-acetonitrile gradient and eluates were monitored at 275 nm. The recoveries of theophylline (spiked at 200 microg/g [tablet] and 50 microg/mL [liquid]), theobromine (spiked at 200 microg/g [tablet] and 50 microg/mL [liquid]) and caffeine (spiked at 1,000 microg/g [tablet] and 250 microg/mL [liquid]) were 97.6-98.7%, 97.3-99.7%, 97.1-105.4%, respectively. The quantitation limits of theophylline, theobromine and caffeine were 10 microg/g (seed, seed powder, tablet and capsule) and 2.0 microg/mL (liquid) each. When this analytical method was applied to commercial dietary supplements, theophylline, theobromine and caffeine were found at concentrations of 4.45 mg/tablet, 5.48 mg/tablet, 139 mg/tablet, respectively. Taking 4 tablets of this product according to the directions on the package could be dangerous to consumers because of possible overdosing of these ingredients.
已开发出一种通过超高效液相色谱法（UPLC）快速、简便地测定含瓜拉那的膳食补充剂中茶碱、可可碱和咖啡因的方法。将茶碱、可可碱和咖啡因从细粉状样品中在沸水浴中用水提取20分钟，然后将提取物过滤，滤液进行UPLC分析。液体样品用水稀释并过滤，滤液进行UPLC分析。UPLC分离在ACQUITY UPLC BEH C18柱（内径2.1mm×50mm，1.7μm，沃特世公司）上进行，以10mmol/L醋酸铵缓冲液（pH 4.0）-乙腈梯度洗脱，洗脱液在275nm处监测。茶碱（加标量为200μg/g[片剂]和50μg/mL[液体]）、可可碱（加标量为200μg/g[片剂]和50μg/mL[液体]）和咖啡因（加标量为1000μg/g[片剂]和250μg/mL[液体]）的回收率分别为97.6 - 98.7%、97.3 - 99.7%、97.1 - 105.4%。茶碱、可可碱和咖啡因的定量限均为10μg/g（种子、种子粉、片剂和胶囊）和2.0μg/mL（液体）。当将此分析方法应用于市售膳食补充剂时，发现其中茶碱、可可碱和咖啡因的浓度分别为4.45mg/片、5.48mg/片、139mg/片。按照包装上的说明服用4片该产品可能会因这些成分的过量摄入而对消费者造成危险。
