Copper phthalocyanine modified SiO2/C electrode as a biomimetic electrocatalyst for 4-aminophenol in the development of an amperometric sensor

Abstract

A selective, simple, and low cost method for 4-aminophenol (4-APh) determination was developed using the mesoporous carbon ceramic SiO₂/50 wt% C (S_BET = 170 m² g⁻¹), composite was prepared by the sol–gel method. The material was fabricated to use as matrix to support copper phthalocyanine (CuPc), prepared in situ on their surface, to assure homogeneous dispersion of the electrocatalyst complex in the pores of the matrix. The pressed disk electrodes made of SiO₂/C/CuPc was tested as amperometric sensors for 4-APh. Under the optimized conditions, at −75 mV vs. SCE in 0.06 mol dm⁻³ Britton–Robinson buffer (BRB) solution (pH 7.0) containing 250 μmol dm⁻³ of H₂O₂, a linear response range for 4APh from 5 up to 230 μmol dm⁻³ was obtained with a sensitivity of 123 nA dm⁻³ μmol⁻¹ cm⁻² and the limit of detection LOD was 2 (±0.002) nmol dm⁻³. The prepared sensors present a stable response during successive determinations. The repeatability, evaluated in terms of relative standard deviation of 3% for n = 10 and μmol dm⁻³ 4-APh. The response time was 1 s and life time 12 months. Finally, the sensor was tested to determine 4-APh in the sample, and gives very good results for its determination. The presence of other phenols like 2-aminophenol, hydroquinone, catechol, cysteine and resorcinol did not show any interference in the detection of 4-APh on this electrode, even in the same concentration with the 4-APh.