茶叶、咖啡、可可和膳食补充剂中咖啡因和可可碱检测方案(毛细管电泳仪)

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重Analytical EquipmentHIGH PERFORMANCECAPILLARY ELECTROPHORESISSYSTEM一www.lumexinstruments.ccm DETERMINATION OF CAFFEINE AND THEOBROMINEIN TEA， COFFEE， COCOA， AND DIETARY SUPPLEMENTS Lumex Method M 04-60-2009 INTRODUCTION The method is used for the determination of the mass fraction of caffeine and theobromine in tea and teaproducts， coffee and coffee products， cocoa and cocoa products， and dietary supplements. MEASUREMENT METHOD Capillary electrophoresis method for the determination of the mass fraction of caffeine and theobromine isbased on micellar electrokinetic chromatography (MEKC). Identification and quantitative determination of thecomponents is performed by direct UV detection at the wavelength of 254 nm. MEASUREMENT RANGE The measurement range for the components is 100 to 100 000 mg/kg (ppm). Preservatives (sorbic and benzoic acids)， sweeteners (acesulfame K， saccharin， aspartame， cyclamate)，sodium glutamate， synthetic dyes， vitamins of the B group， vitamin C， vanillin in the concentrations that aretypical for the products of interest does not influence the determination of the components. ADVANTAGES OF CAPILLARY ELECTROPHORESYS As compared with the HPLC method of determination of caffeine and theobromine， the capillaryelectrophoresis method shows the following advantages： High separation efficiency that is unachievable with HPLC. ● Rapid analysis. ● Low analysis cost. ● No need for expensive chromatographic columns. EQUIPMENT AND REAGENTS The CAPEL capillary electrophoresis system is used in measurements. Data acquisition， collection，processing and output are performed using a personal computer running under WINDOWS@XP/7/8/10operating system with installed dedicated software package ELFORUN. Lumex Instruments complex set， order No 0300002054. EXAMPLES OF REAL ANALYSES BGE： borate， with SDS Capillary： Leff/ Ltot 50/60 cm， ID 75 umInjection： 150 mbar x secVoltage： +25kV The contents on this paper are subject to change without notice.To get more specific information， please contact the representative by sales@lumexinstruments.com    毛细管电泳法用于茶叶和茶叶制品、咖啡和咖啡制品、可可和可可制品和膳食补充剂中咖啡因和可可碱的质量分数的测定。毛细管电泳法可以在波长254 nm下直接通过紫外检测来鉴定和定量测定咖啡因和可可碱的含量。样品中防腐剂（山梨酸和苯甲酸）、甜味剂（安赛蜜、糖精钠、甜蜜素）、谷氨酸钠、合成染料、维生素B、维生素C、香兰素等对样品中咖啡因和可可碱的测定不产生影响。与HPLC法测定咖啡因和可可碱的含量相比，毛细管电泳法具有以下优点：1.比高效液相色谱分离效率高；2.快速分析；3.低分析成本；4.不需要昂贵的色谱柱。