Spectrophotometric determination of lactic acid

An efficient and inexpensive spectrophotometric method has been developed for the determination of lactic acid in the individual state and in food and biological and cultural liquids. The method is based on the spectrophotometric determination of the colored product of the reaction of lactate ions with iron(III) chloride at 390 nm. The optimum conditions of the reaction have been found, and a calibration curve in the range from 0.3 to 10 g/L of lactic acid with the correlation coefficient 0.9999 has been constructed. The method does not require complex sample preparation.