Ultrasensitive electrochemical sensing of dopamine by using dihydroxylatopillar[5]arene-modified gold nanoparticles and anionic pillar[5]arene-functionalized graphitic carbon nitride

An ultrasensitive and highly selective electrochemical method is described for the determination of dopamine (DA). It is based on the use of a multi-functional nanomaterial composed of water-soluble pillar[5]arene (WP5), dihydroxylatopillar[5]arene (2HP5)-modified gold nanoparticles (GNPs), and graphitic carbon nitride (g-C3N4), with an architecture of type 2HP5@GNP@WP5@g-C3N4. The modified GNPs were prepared in the presence of 2HP5 that acts as reducing agent and stabilizer in the formation of GNPs. 2HP5@GNP acts as an electrocatalyst in sensing DA. The WP5@g-C3N4 nanocomposite is obtained by pi interaction between WP5 and g-C3N4 after sonication in the presence of WP5. The composite serves as a host for recognition and gathering DA on the surface of the electrode. The host-guest recognition mechanism between WP5 and DA is studied by H-1 NMR and UV-vis. The electrode, best operated at a working potential of 0.18 V (vs. SCE), works in the concentration range of 0.012-5.0 mu M DA and has a 4 nM detection limit.