Figure 5.

a) Variation of pH with time along with b–f) associated color change for the mixtures of 1 and 2 involving urea‐urease reaction. Initial conditions: (i) [urease]=0.5 mg mL⁻¹, [urea]=0.1 M; (ii) [urease]=0.5 mg mL⁻¹, [urea]=0.06 M; (iii) [urease]=0.3 mg mL⁻¹, [urea]=0.1 M. In all cases, initial concentrations of 1 and 2 are 2 mg mL⁻¹, solvent is DMSO/H₂O (20:80, v/v). For (b–f), methyl red (0.05 mg mL⁻¹) is used to stain the gels.