Ionic strength dependence of formation constants, complexation of molybdenum(VI) with glutamic acid

The complexation of molybdenum(VI) with glutamic acid was investigated in a queous solution ranging in pH from 4 to 9, using polarimetric and spectroph otometric techniques. The composition of the complex was determined by the continuous variations method. It was shown that molybdenum(WT) forms a mono nuclear 1:1 complex with glutamic acid of the type MoO3L-2 at pH 5.8. The p rotonation constants of glutamic acid (using the potentiometric technique) and the stability constant of the complex (using the spectrophotometric tec hnique) were determined at 25 degrees C and at ionic strengths ranging from (0.1 to 1.0) mol dm(-3) sodium perchlorate. The dependence of the protonat ion of glutamic acid and the stability constants of the complex on ionic st rength is described by a Debye-Huckel-type equation.