In-sera selectivity detection of catecholamine neurotransmitters using covalent composite of cobalt phthalocyanine and aminated graphene quantum dots

Here, we constructed an electrochemical sensor for the detection of catecholamine neurotransmitters based on covalent composite of cobalt tetra-(3-carboxyphenoxy) phthalocyanine (CoTCPhOPc) onto aminated graphene quantum dots (AmGQDs). The electrochemical behaviour of the covalent composite modified gold surface was studied using cyclic voltammetry, differential pulse voltammetry, square wave voltammetry and electrochemical impedance spectroscopy. The electrochemical sensor fabricated using gold surface with AmGQD-CoTCPhOPc exhibited enhanced electrical conductivity. The fabricated electrochemical sensor displayed excellent analytical performance towards the detection of dopamine (DA), norepinephrine (NOR) and epinephrine (EP). The analytical parameters were linear within the concentration range of 1.0 to 50 μM with detection limits of 0.20 µM (DA), 0.45 µM (NOR), and 0.23 µM (EP) using S/N = 3. Furthermore, the fabricated electrochemical sensor exhibited good ability to suppress the background current due to ascorbic acid (AA), a major interferent during detection of DA, EP and NOR analytes. More importantly, the developed covalent electrochemical sensor was successfully utilized for the detection of catecholamine neurotransmitters in newborn calf serum samples with high recovery percentages.