PHOTOCHEMICAL-REACTION OF TRICHLOROACETIC-ACID WITH DIPHENYLAMINE AND ITS ANALYTICAL APPLICATION

A method for the determination of trichloroacetic acid (TCA) in a simple spectrophotometric way has been described. It is based on the photochemical reaction of TCA with diphenylamine (DPA) which forms a green colored product (lambda(max): 652 nm). The relative standard deviation for all measurements is <7%. A linear calibration graph is obtained in the concentration range of 610 to 2875 ppm with a correlation coefficient 0.990. The method is simple, rapid and does not require any costly and hazardous chemical. The effect of solvent, reagent concentration, time of irradiation etc. have been discussed. Extraction of TCA from contaminated water or urine with upto 10 fold increase in concentration followed by photochemical reaction and absorption measurement showed good correlation with the theoretical value. The interference by chloroacetic acid (MCA), dichloroacetic acid (DCA), chloroform (CHCl3), carbon tetrachloride (CCl4), trichloroethylene (TCE), and perchloroethylene (PCE) have also been studied.