Determination Of Caffeine In Coffee Using Uvvis Spectrophotometry

Spectrophotometric method was developed for the determination of the amount of caffeine inrncoffee samples. The Uv/vis spectra of pure caffeine in water and dichloromethane were obtainedrnwith peak absorption at λmax 271 and 275 nm, respectively. The developed method showedrnlinearity for the determination of caffeine in the range of 2.5x10-5 mol dm-3 to 1.25x10-4 mol dm-3.rnThe method also showed good precision, accuracy with limits of detection 2.14 and 1.79 mg/l inrnwater and dichloromethane, respectively. The relative standard deviation for the determination ofrna 2.0x10-5 mol dm-3 caffeine was 4.53% and 3.72% (n=5) in water and dichloromethane,rnrespectively. The molar decadic absorption coefficients of caffeine in water and dichloromethanernat maximum wavelength are 1031.2+0.036 and 1004.4+0.029 m2 mol-1, respectively. Analyticalrnparameters were investigated primarily; the method was applied to quantify the amount ofrncaffeine in coffee samples. The method was found to be fast, simple, cost effective andrnenvironmental friendly for the determination of caffeine in aqueous solution coffee samples withrnsatisfactory results.rnKeywords: Coffee Arabica, Caffeine, Absorbance, Uv/vis spectrophotometry, Extraction

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