DETERMINATION OF CAFFEINE CONTENT IN DIFFERENT BRANDS OF PURE COFFEE, INSTANT COFFEE AND TEA AVAILABLE IN THE NAYPYITAW MARKET

Caffeine is a naturally found in leaves, seeds or fruits of over 63 plants species worldwide and most common sources are coffee, cocoa beans, cola nuts and tea leaves. Caffeine is a pharmacologically active substance and depending on dose, can be mild CNS stimulant, improve cardiac performance, increase heartbeat rate, and increase brain circulation. An excessive intake of caffeine in some persons appears to augment sensitivity of heart to emotional, increase the incidence of extra systoles and other arrhythmias. For healthy adults, USFDA has cited 400 mg/day as an amount not generally associated with negative health effects. The objective of this study was to determine caffeine content in different brands of pure coffee, instant coffee and tea available in Naypyitaw market. Pure coffee, instant coffee and tea samples of fourteen different brands collected from retail shops in Naypyitaw were coded into C1-C14. HPLC condition for caffeine was achieved on VP-ODS (C18) column with mobile phase consisting of methanol: water (50:50 % v/v) at a flow rate of 1mL/min and UV detection at 254 nm. Linearity of method was check from 6.25-100ppm and correlation coefficient was 0.9999. The caffeine contents in pure coffee samples were 2.74±0.111 mg/g (C1), 0.87±0.003 mg/g (C2), 3.64±1.39 mg/g (C3), 5.26±0.07 mg/g (C4) and 3.03±0.004 mg/g (C5). The caffeine contents in instant coffee samples were 0.28±0.003 mg/g (C6), 0.24±0.002 mg/g (C7), 0.4±0.009 mg/g (C8) and 0.31±0.008 mg/g (C9). The caffeine contents in tea samples were 0.93±0.014 mg/g (C10), 0.92±0.002 mg/g (C11), 0.29±0.001 mg/g (C12), 0.79±0.004 mg/g (C13) and 0.63±0.002 mg/g (C14). The findings showed pure coffee has highest caffeine content followed by tea and instant coffee. The consumer should drink not more than USFDA recommended caffeine level (400mg/day) especially in pure coffee drinker. Keywords— HPLC, USFDA, Caffeine, CNS, VP-ODS