Determination on Amino Acids Contents in Tobacco by Ninhydrin Color Reaction

Amino acids content in tobacco was determined by spectrophotometric method using ninhydrin color reaction.The experimental conditions was analyzed and determined as follows:1.0 ml of phosphate buffer(pH 6.70);maximum absorption wavelength,570 nm;and 1.5 ml of 2% ninhydrin solution.The coloring time and stability were also studied.The sample solution having no color reaction was used as reference,which eliminated the effects of pigments and impurities in the liquid on detection and improved accuracy.This method is simple,fast,highly sensitive,low-cost,and especially suitable for detection of small quantity and multiple batches in tobacco research.