2.1. MaterialsGly-Tyr (SRL, 99.0%),

2.1. MaterialsGly-Tyr (SRL, 99.0%), ninhydrin (Merck, 99.0%), CTAB (Merck, 99.0%), acetic acid (Merck, 99.0%), and sodium acetate (Merck, 99.0%) were used as received. The stock solutions of Gly-Tyr, ninhydrin, and CTAB were prepared in CH3COONa–CH3COOH buffer solution (pH 5.0), which was prepared by mixing of 30 cm3 of 0.2 mol dm−3 acetic acid and 70 cm3 of 0.2 mol dm−3 sodium acetate (Britton, 1942). Double-distilled and deionized water (specific conductance (1–2) × 10−6 ohm−1 cm−1) was used throughout. The pH measurements were made using ELICO LI-122 pH meter in conjugation with a combined electrode (glass-saturated calomel electrode).

2.1. Materials
Gly-Tyr (SRL, 99.0%), ninhydrin (Merck, 99.0%), CTAB (Merck, 99.0%), acetic acid (Merck, 99.0%), and Sodium acetate (Merck, 99.0%) were Used As Received. The stock solutions of Gly-Tyr, ninhydrin, and CTAB were prepared in CH3COONa-CH3COOH buffer solution (pH 5.0), which was prepared by mixing of 30 cm3 of 0.2 mol dm-3 acetic acid and 70 cm3 of 0.2 mol dm-3. sodium acetate (Britton, 1942). Double-distilled and deionized water (specific conductance (1-2) × 10-6 ohm-1 cm-1) was used throughout. The pH measurements were made ​​using ELICO LI-122 pH meter in conjugation with a combined electrode (glass-saturated calomel electrode).

2.1. Materials
Gly-Tyr, (SRL 99.0%), ninhydrin, (Merck 99.0%), CTAB, (Merck 99.0%), acetic, acid (Merck 99.0%), and sodium. Acetate (Merck 99.0%), were used as received. The stock solutions, of Gly-Tyr ninhydrin and CTAB, were prepared in CH3COONa - CH3COOH. Buffer solution (pH 5.0), which was prepared by mixing of 30 cm3 of 0.2 mol dm − 3 acetic acid and 70 cm3 of 0.2 mol dm − 3 sodium, acetate (Britton 1942). Double-distilled and deionized water (specific conductance (1 - 2) × 10 − 6 ohm − 1. Cm − 1) was used throughout. The pH measurements were made using ELICO LI-122 pH meter in conjugation with a combined electrode. (glass-saturated calomel electrode).