Abstract
The first and second derivative spectra of liquid foods were measured for examining synthetic dyes added in them. For commercial soft drinks, there was a little difference between the found concentration of dyes used and the concentration in the eluate after wool dyeing process by this procedure. By the second derivative spectrophotometry, food colors were directly and satisfactorily detemined even in. turbid lactic drinks, of which turbidity were found no influence on the spectra of dyes. Above all, the dyestuff in these drinks was identified by comparing its derivative spectrum (especially second derivative spectrum) with that of dyestuff standard.
A synthetic dye in liquid foods which was qualitatively determined by this procedure was also confirmed by thin layer chromatography.
