Highly sensitive Pb2+ sensor based on rod-like poly-tyrosine/Bi modified glassy carbon electrode combined with electrodeposition to eliminate Cu2+ interference

A rod-like poly-tyrosine membrane modified glassy carbon electrode (p-Tyr/GC) was first prepared and characterized by CV, EIS and SEM, which can improve electroactive area and electron transfer. Then a Bi/p-Tyr/GC composite electrode was prepared by in situ Bi plating. Taking the Bi/p-Tyr/GC's response to 0.25 mu mol.L-1 Pb2+ as reference, the optimal conditions for Bi/p-Tyr/GC preparation and test were obtained with Tyr concentration, scan number, Bi3+ concentration, pH and accumulation potential being 2.0 mmol.L-1, 20, 3.0 mu mol.L-1, 6.5 and -1.3 V, respectively. Under optimal conditions, the linear equation of Bi/p-Tyr/GC's response to Pb2+ (1.0 nmol.L-1 to 3.0 mu mol.L-1) was ip (mu A) = 0.6184 + 105.5c (mu mol.L-1) (R-2 = 0.9987) with a detection limit of 0.12 nmol.L-1 (3S/k). For the first time, the elimination of Cu2+ interference for Pb2+ determination was studied by electrodeposition. The Bi/p-Tyr/GC electrode was successfully used for Pb determination in preserved duck eggs with a recovery of 92.1-97.9% and RSD less than 3.5%. The developed Pb2+ sensor has high sensitivity and wide linear range. More importantly, the electrochemical method for eliminating Cu2+ interference has high selectivity and wide application range, which has important reference value for the development of other heavy metal ion sensors in complex samples.

Automated summary

A rod-like poly-tyrosine membrane modified glassy carbon electrode (p-Tyr/GC) and a Bi/p-Tyr/GC composite electrode were prepared and optimized for Pb2+ detection. The Bi/p-Tyr/GC electrode showed high sensitivity and wide linear range for Pb determination in preserved duck eggs, with successful elimination of Cu2+ interference. The developed electrochemical method has high selectivity and broad application potential for heavy metal ion sensors in complex samples.