Densitometric determination of taurine and L-lysine hydrochloride in an energy drink and in multi-vitamin syrup, and validation of the method

A simple and rapid densitometric method has been developed for determination of taurine and lysine in 'energy drinks' and in syrup preparations. After dissolution and dilution in 4:1 96% ethanol-water the solutions were spotted on precoated silica gel plates which were then eluted with n-butanol-glacial acetic acid-96% ethanol-water, 4 + 2 + 3 + 3 (v/v). Quantitative evaluation was performed by measuring the absorbance reflectance of the analyte spots at λ = 490 nm. This densitometric method is selective, precise, and accurate and can be used for routine analysis of these pharmaceutical preparations in quality-control laboratories.