The main analytical parameters for a spectrophotometric method of amino acid analysis were determined. The Ringbom Curve at 550 nm for the determination of L (+) Arginine with o-diacetylbenzol showed that the ideal concentration range is 150 to 500 μg / ml. The relative precision was 5.26%. For determination of L (-) Asparagine with o-diacetylbenzol, the Ringbom Curve at 547nm accounted for the ideal concentration range of 40-200 μg / ml. The relative precision was 1.43%. For the etermination of L (+) Lysine o-diacetylbenzol, the Ringbom Curve at 547 shows the concentration range of 8 to 44 μg / ml as ideal. The relative precision was 0.18%. Among the substances studied, it was observed that absorption spectra of thiamine hydrochloride (Vitamin B 1 ), riboflavin hydrochloride (Vitamin B2 ), pyridoxine hydrochloride (Vitamin B 6 ), carnitine, buclisina, folic acid (vitamin M) and nicotinamide (vitamin PP) , and the absorption spectra of these compounds with-diacetilbenzol not interfere with the absorption of L - amino acids (+) Arginine, L (-) Asparagine, L (+) Lysine in their determinations. The absorption of cyanocobalamin compounds (Vitamin B 12 ) and ɤammonobutyric acid or the observations of these compounds in the presence of o-diacetylbenzol interfere with the determinations studied. The absorption profiles of three different pharmaceutical specialties formulations were obtained with o-diacetylbenzol, showing the viability of the direct determination of the studied amino acids
