Extraction And Quantification of Caffeine in Different Tea Bags Using Uv-Visible Spectroscopy and Iodometric Back Titration
Ibrahim Isah Fagge
Kamal Nura Abubakar
Saudatu Ja’afaru Chinade
Ridwanu Murtala
Sunusi Yahaya Hussaini
Ibrahim Usman Kutama
Abstract
This study aimed to compare the caffeine content across different commercial tea brands and to correlate the results with processing methods, with a discussion of implications for consumer health and labeling practices. The caffeine content in three commercial tea samples (one green tea and two black teas) was comparatively analyzed. Caffeine was extracted from the samples using a Soxhlet apparatus with dichloromethane as the solvent. The crude caffeine was then quantified using two independent analytical techniques: UV-visible spectrophotometry and iodometric back titration. Results from both methods were consistent, revealing that the green tea sample (Sample 1) contained a significantly higher caffeine yield (472 mg per 6.67 g of tea) than the two black tea brands (268 mg and 222 mg, respectively). UV-visible analysis at 274 nm showed a correspondingly higher absorbance for the green tea extract (2.5) compared to the black tea extracts (2.2). Similarly, iodometric back titration indicated a greater consumption of sodium thiosulfate titre for the green tea sample, confirming a higher concentration of caffeine. This finding challenges the common assumption that black tea inherently contains more caffeine due to the fermentation process. The calculated caffeine content was approximately 7.1% for the green tea, compared to 4.1% and 3.3% for the black teas. The study highlighted significant brand-specific variations in caffeine content, which has direct implications for consumer awareness and industry labeling practices. The reliability of the analytical approach was validated by the strong concordance between the results obtained from the two distinct quantification methods.
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