Tetrabutylammonium bromide(TBAB), a cationic surfactant influence on chemical speciation of Copper(II) and Zinc(II) ternary complexes with L-glutamine(Gln) and Succinic acid(Suc) have been studied with a Control Dynamics-APX 175E/C pH-meter at an ionic strength of 0.16 mol dm-3 and temperature 303 K in varying concentrations (0.0-3.0%, w/v). Various models for the species of these biologically important ligands are refined by using the computer programs SCPHD and MINIQUAD75. The active forms of both copper(II) and zinc(II) are MLX, MLX2 and MLXH. The trend in the formation constants and TBAB influence are explained on the basis of electrostatic and non-electrostatic forces. The species distribution with pH at different solvent composition, formation equilibria and plausible structures for the formed specie are also presented in the present study