Evaluation of Caffeine in Soft and Energy Drinks by Means of UV/Visible Spectrophotometer

NERTIL XHAFERAJ*, ANISA PECULI, ANILA KOPALI, AIDA SHKURTI, FATJON HOXHA

1 Agricultural University of Tirana, Faculty Biotechnology and Food, Department of Agro-Food Technology, Street ‘PaisiVodica’, Koder-Kamez, 1029 Tirana, Albania

*Corresponding author e-mail: nxhaferaj@ubt.edu.al

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Abstract

The UV-VIS spectrometry is a method frequently used for routine caffeine determination in beverages. Caffeine absorb at UV-VIS region with maximum absorption band at 271 nm. In the present work we undertook various experiments to determine the pH and levels of caffeine concentration in ten soft drinks and five energy drinks available in local market in Albania. pH levels were measured by pH meter. Calibration solutions were prepared in the concentration range of 1-25 ppm from a 100 ppm stock solution. Concentration of caffeine in drinks was performed by a simple and fast standard UV spectrophotometric method at 271 nm. The minimum caffeine content of soft drinks was observed in Brand-5(24.55 mg/L), while the highest concentration of caffeine was observed in Brand-9 (79.46 mg/L). Unlike the soft drinks, the concentration of caffeine in energy drinks were slightly higher with minimum amount at Brand-4 (62 mg/L) and maximum at Brand-5 (152 mg/L). The pH range of soft drinks were (2.51 to 3.34) and in energy drinks (2.33 to 3.49)

Keywords: Caffeine, UV/Visible Spectrophotometer, Soft and energy drinks

 

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