Caffeine quantification in dietary supplements by fluorescence using bovine serum albumin

Abstract

Caffeine (1,3,7-trimethylxanthine; CF), is a substance found naturally in the leaves, beans and fruits of a variety of plants. Although it is regularly consumed by a large percentage of adults, in Argentina recently the young have been added to this group. Attending to the health risks, many countries have started action to establish the regulatory boundaries around CF. A new method for the determination of caffeine based on the quenching of Bovine serum albumin (BSA) fluorescence. When the alkaloid CF is presents (quencher), the protein?s fluorescence emission is diminished. The diminution of the signal is proportional at caffeine concentration. The effect of experimental parameters, including the nature of the buffer and pH, and the nature of the surfactant and concentration were investigated by means univariation assays. Under optimum experimental conditions, a detection and quantification limits of 1.9 and 6.4 mg l−1 were obtained, respectively. A linear range was achieved varying from concentrations of 6.4 to 94 mg l−1 (r2 = 0.997). Satisfactory recovery values were obtained using the method of standard addition, confirming the feasibility of this method for caffeine determination in energising dietary supplements and energy drinks. In order to obtain the known advantages of on-line procedure, a flow injection manifold will be sketched and quality analytical parameter will be evaluated.