Fig. 1

The effect of Cu²⁺ ions concentration (1.00 × 10^–7–5.00 × 10^–3 mol L⁻¹) on the fluorescence intensity of pefloxacin (2.00 × 10^–7 mol L⁻¹) at 25 °C (λex at 330, λem at 435 nm) a [Hpf] = 2.00 × 10^–7 mol L⁻¹, b upon addition of [Cu²⁺] = 1.00 × 10⁻⁷ mol L⁻¹, c upon addition of [Cu²⁺] = 4.00 × 10^–7 mol L⁻¹, d upon addition of [Cu²⁺] = 1.00 × 10^{− 4} mol L⁻¹, e upon addition of [Cu²⁺] = 2.00 × 10^–4 mol L⁻¹, f upon addition of [Cu²⁺] = 3.00 × 10^–4 mol L⁻¹, g upon addition of [Cu²⁺] = 1.00 × 10^–3 mol L⁻¹, h upon addition of [Cu²⁺] = 2.00 × 10^–3 mol L⁻¹, i upon addition of [Cu²⁺] = 5.00 × 10^–3 molL.⁻¹