"RIV/00216305:26310/07:PU71920" . . . "Praha" . "Guarana or Coffee & Tea or Coca cola"@en . "guarana, caffeine, theobromine, theophyline, HPLC, energy drinks"@en . . . "26310" . . . . "978-80-7194-937-4" . "Univerzita Pardubice" . . . "The guarana powder or extract containing foodstuffs are commonly available in shops in Czech Republic. The foodstuffs can be divided into three categories: drinks, sweets and food supplements. Guarana extracts are most frequently constituents of energy drinks, e.g. Kamikaze or Erektus. Juice with a guarana extract and tea bags containing guarana powder are marketed, too. Guarana powder or extract is frequent constituent of chocolate bars, muesli bars, chewing gums, honey and sweets. Food supplements with guarana are sold as tablets or pure guarana extract, too. Liquid chromatography proved to be so much effective in analyses of the purine alkaloids caffeine, theobromine and theophyline contained in guarana that these alkaloids were determined simultaneously in one run. Stationary phase was a silica gel with chemically bonded octadecyl groups. Mobile phase consisted of acetonitrile and water that was acidified in need depending on mild differences in properties of utilized reversed phase columns. Photo"@en . . "Vespalcov\u00E1, Milena" . "[0053BA222920]" . . "RIV/00216305:26310/07:PU71920!RIV12-MSM-26310___" . "Guarana or Coffee & Tea or Coca cola" . . "423717" . . . "I, Z(MSM0021630501)" . "The guarana powder or extract containing foodstuffs are commonly available in shops in Czech Republic. The foodstuffs can be divided into three categories: drinks, sweets and food supplements. Guarana extracts are most frequently constituents of energy drinks, e.g. Kamikaze or Erektus. Juice with a guarana extract and tea bags containing guarana powder are marketed, too. Guarana powder or extract is frequent constituent of chocolate bars, muesli bars, chewing gums, honey and sweets. Food supplements with guarana are sold as tablets or pure guarana extract, too. Liquid chromatography proved to be so much effective in analyses of the purine alkaloids caffeine, theobromine and theophyline contained in guarana that these alkaloids were determined simultaneously in one run. Stationary phase was a silica gel with chemically bonded octadecyl groups. Mobile phase consisted of acetonitrile and water that was acidified in need depending on mild differences in properties of utilized reversed phase columns. Photo" . "2"^^ . "2"^^ . . "2"^^ . . "Guarana or Coffee & Tea or Coca cola" . . . "Vitamins 2007, Nutrition and Diagnostics" . "2007-09-19+02:00"^^ . . "Pardubice" . "Kalvodov\u00E1, Jana" . . . "Guarana or Coffee & Tea or Coca cola"@en .