Nitric oxide measurement in biological and pharmaceutical samples by an electrochemical sensor

A nitric oxide (NO) electrochemical sensor was developed via one-step construction of gold nanoparticles (GNPs)–chitosan (CS) nanocomposite sensing film on a glassy carbon electrode (GCE) surface. This method is very simple and convenient. The GNPs–CS film which is controllable and stable exhibits catalytic activity to NO oxidation. The anodic peak potential significantly shifted negatively compared with that at bare GCE. The high sensitivity and good stability of developed method have been coupled to a wide linear range from 3.60 × 10⁻⁸ to 4.32 × 10⁻⁵ M for the quantitative analysis of NO. The detection limit of 7.20 nM is much lower than the vast majority of reported methods. This NO sensor has been successfully applied to NO measurement in biological and pharmaceutical samples. Real-time amperometric data show that the addition of L-arginine (L-Arg) can cause a slow release of NO from a whole rat kidney with a maximum concentration of ca. 150 nM. The concentration of NO monitoring from the drug sample was calculated to be ca. 1.60 μM.