Rapid and selective detection of dopamine in human serum using an electrochemical sensor based on zinc oxide nanoparticles, nickel phthalocyanines, and carbon nanotubes

Composite materials have gained significant attention owing to the synergistic effects of their constituent materials, thereby facilitating their utilization in new applications or in improving the existing ones. In this study, a composite based on nickel phthalocyanine (NiTsPc), zinc oxide nanoparticles (ZnONPs), and carbon nanotubes (CNT) was developed and subsequently immobilized on a pyrolytic graphite electrode (PGE). The PGE/NiTsPc-ZnONPs-CNT was identified as a selective catalytic hybrid system for detection of neurotransmitter dopamine (DA). The electrochemical and morphological characterizations were conducted using atomic force microscopy (AFM). Chronoamperometry and differential pulse voltammetry (DPV) were used to detect DA and detection limits of 24 nM and 7.0 nM was found, respectively. In addition, the effects of some possible DA interferents, such as ascorbic acid, uric acid, and serotonin, on DA response were evaluated. Their presence did not show significant variations in the DA electrochemical response. The high specificity and sensitivity of PGE/NiTsPc-ZnONPs-CNT for DA enabled its direct detection in human serum without sample pretreatment as well as in DA-enriched serum samples, whose recovery levels were close to 100%, thereby confirming the effectiveness of the proposed method. In general, PGE/NiTsPc-ZnONPs-CNT is a promising candidate for future applications in clinical diagnosis.