Study on Cd2+ Determination Using Bud-like Poly-L-Tyrosine/Bi Composite Film Modified Glassy Carbon Electrode Combined with Eliminating of Cu2+ Interference by Electrodeposition

A bud-like poly-L-tyrosine/Bi modified glassy carbon electrode (p-Tyr/Bi/GC) was prepared by CV and in situ Bi plating, whose conductivity and membrane morphology were characterized by CV, EIS and SEM, respectively. The p-Tyr membrane can effectively promote the enrichment of Cd²⁺. The optimal Tyr concentration and scanning number for p-Tyr/GC preparation were 2.0 mmol ? L^?1 and 35, while the optimal Bi³⁺ concentration, pH and Cd²⁺ accumulation potential in test medium were 3.0 μmol ? L^?1, 6.5 and ?1.3 V, respectively. The linear equation of p-Tyr/Bi/GC's response to Cd²⁺ (1.0 nmol ? L^?1 to 2.0 μmol ? L^?1) was i_p (μA) = ?0.6809 + 100.2c (μmol ? L^?1) (R² = 0.9985) with a detection limit of 0.11 nmol ? L^?1 (3S/N). The elimination of interference caused by Cu²⁺ in sample was studied by electrodeposition. The p-Tyr/Bi/GC electrode was successfully used for detecting Cd in rice samples with good reliability and accuracy. The developed Cd²⁺ sensor exhibits high sensitivity, wide linear range and low detection limit, especially the designed method of eliminating Cu²⁺ interference has the characteristics of high selectivity, simple operation and wide application range.