The reaction of glutamic acid and trinitrobenzenesulfonic acid--kinetic study and analytical application

Some kinetic aspects of the reaction of glutamic acid (GLU) and Trinitrobenzenesulfonic acid (TNBS) were studied spectrophotometrically (420 nm), under pseudo-first order reaction conditions. The effect of GLU, TNBS, SO(2-)(3) and H(+) had been investigated. Working curves for the initial rates IR versus GLU] are linear in the range 7.5-30.0 mM. The regression equation is IR = (8 +/- 8)E - 6 + (39 +/- 0.5).GLU] and the correlation coefficient r = 0.9998. The limit of quantitation is 1.5 microM GLU and the relative standard deviation of the method 1.2%. The kinetics of the interfering TNBS hydrolysis reaction in alkaline range of pH, as well as the effect of sulfite concentration on the main reaction, are also presented. The analytical application of the reaction for the kinetic spectrophotometric assay of GLU and other amino acids, as well as TNBS, is presented and the relevant advantages and disadvantages of the method are discussed.