Simultaneous electrochemical detection of uric acid and xanthine based on electrodeposited B, N co-doped reduced graphene oxide, gold nanoparticles and electropolymerized poly (L-cysteine) gradually modified electrode platform

A glassy carbon electrode (GCE) was modified with a nanocomposite synthesized from electropolymerized L-cysteine (poly L-cys), gold nanoparticles (AuNPs), and B, N co-doped reduced graphene oxide (B, N-RGO). The sensor is depicted to enable the individual and simultaneous voltammetric determination of two purine derivatives, uric acid (UA) and xanthine (XA). Under the optimal conditions, the sensor displayed a good linear relationship between 3.0 nM and 3.0 µM for UA and 0.3 nM and 3.0 µM for XN in simultaneous determination. The limit of detection (LOD) and sensitivity are estimated to be 0.9 nM and 1.908 µA µM -1 cm−2, for UA and 90.0 pM and 0.846 µA µM−1 cm−2 for XA, respectively. The modified GCE demonstrates several benefits, including high sensitivity and selectivity, low LOD, high surface-to-volume ratio, and good electrocatalytic activity towards UA and XA. The sensor was used successfully for the simultaneous measurement of UA and XA in human blood serum samples.