A new disposable amperometric NADH sensor based on screen-printed electrode modified with reduced graphene oxide/polyneutral red/gold nanoparticle

A new amperometric NADH sensor was developed based on screen-printed electrode (SPCE) modified with reduced graphene oxide (RGO), polyneutral red (PNR) and gold nanoparticles (AuNP). Electrochemical behaviour of NADH on SPCE/RGO/PNR/AuNP was investigated. The prepared sensor showed a high electrocatalytic effect on the oxidation of NADH. The sensor response for NADH was investigated as a function of pH and working potential. Optimum values of these parameters in the NADH determination were found as 7.0 for pH and +0.15 V for working potential. Sensitivity, linear range, limit of detection and limit of quantification of the sensor were found to be 8.72 μAmM⁻¹, 5 to 3170 μM, 0.384 μM and 1.18 μM, respectively. The relative standard deviation (RSD) was calculated to be 1.93% (for n = 10). The operational stability studies have shown that the initial amperometric response of sensor to NADH decreased by 56.15% at the 60th day. Storage life studies have shown that the sensitivity of the biosensor decreased by 48.72% at the end of 12 weeks. The developed sensor has been tested for NADH determination in the human serum sample. The developed NADH sensor is promising to be used for NADH analysis in human serum samples as simple, practical and disposable device without requiring laborious sample pre-treatment producers.