HPLC Determination of Caffeine and Theobromine in Coffee, Tea, and Instant Hot Cocoa Mixes |
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Authors: | JOAN L BLAUCH STANLEY M TARKA JR |
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Affiliation: | Authors Blauch and Tarka are affiliated with Hershey Foods Corporation Technical Center, 1025 Reese Ave., Hershey, PA 17033. |
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Abstract: | Popular brands of instant and ground coffee, instant and bag tea, and instant hot cocoa mixes were prepared according to manufacturer's directions and analyzed for caffeine and/or theobromine content. After extraction into boiling water, the methylxanthines were separated by high performance liquid chromatography using a reverse phase C18 column and a mobile phase of acetonitrile and water (8:92, v/v). Caffeine content ranged from 32.4–35.0 mg/cup in instant tea, 30.2–67.4 mg/cup in bag tea, 1.0–7.8 mg/cup in instant hot cocoa mixes, 46.7–67.6 mg/cup in instant coffee, and 93.0–163.5 mg/cup in ground coffee. Theobromine concentrations ranged from 1.4–2.3 mg/cup in instant tea, 1.2–4.4 mg/cup in bag tea, and 39.5–79.5 mg/cup in instant hot cocoa mixes. |
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