Figure 2.

a) Chronopotentiometric signals for 1 μg mL⁻¹ (I) and 1 ng mL⁻¹ thrombin (II) obtained by measuring the secondary aptamer TBA-2 without and with PCR amplification, respectively. b) Responses of the blank solution (without thrombin; I), and of solutions containing 0.1 μg mL⁻¹ myoglobin (II) and 0.1 μg mL⁻¹ lysozyme (III). Binding times for the target protein and secondary aptamer, 30 min each. After acid digestion and purification, 1 mL of acetate buffer (0.5M, pH 5.8) containing 2 ppm Cu²⁺ was added to the detection cell. Accumulation: 2 min at −0.05 V; stripping current, +3 μA.