Non-enzymatic detection of bilirubin based on a graphene–polystyrene sulfonate composite

Abstract

We report, a selective, non-enzymatic bilirubin (BR) detection through catalytic oxidation on a reduced graphene oxide (RGO)–poly styrene sulfonate (PSS) composite film spin coated on a glassy carbon electrode. The catalytic ability, stability, morphology and composition of the RGO–PSS composite, were evaluated using voltammetric, spectroscopic and microscopic techniques. The experimental variables influencing the analysis of bilirubin were optimized in terms of active material composition, pH and serum albumin concentration in blood. At the optimized condition, the linear dynamic range was found to be 0–450 μM, with a sensitivity of 0.16 μA μM⁻¹ cm⁻² and the detection limit was 2.0 μM. The modified electrode possesses good stability, reproducibility and selectivity towards bilirubin determination. The real sample analysis demonstrates the scope of the RGO–PSS composite modified electrode for practical clinical diagnosis.