The use of carbon-based nanomaterials conjugated to cobalt phthalocyanine complex in the electrochemical detection of nitrite

This work reports on the non-covalent conjugation of carbon-based nanomaterial with tris(4-tert-butylphenoxy)-(5-phenoxylpicolinic acid) phthalocyanato cobalt (II) (CoPc). The CoPc was π-stacked onto the graphene quantum dots (GQDs), nitrogen-doped quantum dots (NGQDs) and the single-walled carbon nanotubes (SWCNTs) yielding CoPc@GQDs, CoPc@NGQDs and CoPc@SWCNTs, respectively. The hybrids were characterised using various analytical techniques. The CoPc and conjugates were studied electrochemically and used as electrocatalysts in the electrooxidation/detection of nitrite. The sensitivities (3–28 μAμM−1), catalytic rate constants (1.8 × 102–5.42 × 104 M−1 s−1) and limits of detection (0.17–1.70 μM) obtained herein show that the electrocatalysts have good nitrite detection capabilities, comparable to those in literature.