Voltammetric determination of isoproterenol using a 5-amino-2′,4′-dimethoxybiphenyl-2-ol modified carbon nanotube paste electrode

A new electrochemical sensor for determination of isoproterenol (IP) is described. The sensor is based on carbon paste electrode (CPE) modified with 5-amino-2′,4′-dimethoxybiphenyl-2-ol (5ADMB) and takes the advantages of carbon nanotubes (CNTs). Under the optimum pH of 7.0, the oxidation of IP occurs at a potential about 210 mV less positive than that of the unmodified CPE. The oxidation currents increased linearly with two concentration intervals of IP, one is 0.09 to 20.0 μmol/L and, the other is 20.0 to 400.0 μmol/L. The detection limit (3σ) obtained by square wave voltammetry (SWV) was 39.0 nmol/L. The practical application of the modified electrode was demonstrated by determining IP in IP ampoule, urine and human blood serum samples.