Fig. 1. Absorption (A) and emission (B) spectrum of HSA.

Fig. 2. Absorption spectrum of HSA in the absence and presence of colloidal TiO₂ in the concentration range of 0–6 × 10⁻⁴ M.

Fig. 3. Fluorescence quenching of HSA in the presence of various concentration of colloidal TiO₂, [TiO₂] = 0–6 × 10⁻⁵ M.

Fig. 4. Stern–Volmer plot for the steady-state fluorescence quenching of HSA by colloidal TiO₂.

Fig. 5. Plot of log[(F₀ − F)/F] vs. log[Q].

Fig. 6. Synchronous fluorescence spectrum of HSA with Δλ = 15 nm in the absence and presence of colloidal TiO₂ (0–3 × 10⁻⁵ M).

Scheme 1. Mechanism for the interaction between colloidal TiO₂ and HSA.