Electrocatalytic detection of biological nitric oxide at an ultramicroelectrode modified with an electrodeposited CuPtCl6 film

An inorganic polymer [CuPtCl6. CuPtCl4](n), using CuPtCl6 as the precursor monomer, was electrodeposited onto a carbon fiber ultramicroelectrode. The modifier film displays excellent electrocatalytic activity for the oxidatio n of NO at similar to 700 mV (vs. SCE). The modified electrode was prepared by continuous cyclic scanning between 700 and -800 mV in a solution contai ning CuCl2 and K2PtCl6. A Nafion membrane coating was used to avoid the int erference of nitrite. The effect of film thickness, pH, and the interfering species to NO detection have been studied. With differential pulse voltamm etry, the linear response range is from 1 x 10(-7) M to 2 x 10(-4) M with a sensitivity of 19.7 +/- 0.6 mu A cm(-2) mu M-1. With amperometry, the line ar range of detection is from 1 x 10(-8) M to 2 x 10(-4) M with a detection limit of 5 nM (signal : noise = 3), An electrochemical sensor for the dete ction of biological NO is described based on this modification of a 5 mu m tip-sharp carbon fiber electrode. The application of this sensor in the det ection of biological NO was demonstrated by measuring ATP-stimulated NO rel ease from freshly dissected chicken cochlea neuron cells. (C)1999 Elsevier Science B.V. All rights reserved.