Preparation of chitosan grafted graphite composite for sensitive detection of dopamine in biological samples

•A novel DA sensor based on GR-CS composite.•Low overpotential detection of DA with enhanced sensitivity.•The LOD of 4.5 nM for DA is achieved.•Practicality has been demonstrated in biological samples.

The accurate detection of dopamine (DA) levels in biological samples such as human serum and urine are essential indicators in medical diagnostics. In this work, we describe the preparation of chitosan (CS) biopolymer grafted graphite (GR) composite for the sensitive and lower potential detection of DA in its sub micromolar levels. The composite modified electrode has been used for the detection of DA in biological samples such as human serum and urine. The GR-CS composite modified electrode shows an enhanced oxidation peak current response and low oxidation potential for the detection of DA than that of electrodes modified with bare, GR and CS discretely. Under optimum conditions, the fabricated GR-CS composite modified electrode shows the DPV response of DA in the linear response ranging from 0.03 to 20.06 μM. The detection limit and sensitivity of the sensor were estimated as 0.0045 μM and 6.06 μA μM−1 cm−2, respectively.

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