Dioctylamine-sulfonamide-modified carbon nanoparticles as high surface area substrates for coenzyme Q10-lipid electrochemistry

Dioctylaminesulfonamide-modified carbon nanoparticles are characterised and employed as high surface area substrate for (i) coenzyme Q10 and (ii) 1,2-dimyristoyl-sn-glycero-3-phosphocholine (or DMPC) - Q10 redox processes. The carbon nanoparticles provide a highly hydrophobic substrate with ca. 25Fg -1 capacitance when bare. Q10 or DMPC-Q10 immobilised onto the carbon nanoparticles lower the capacitance, but give rise to well-defined pH-dependent voltammetric responses. The DMPC-Q10 deposit shows similar characteristics to those of Q10, but with better reproducibility and higher sensitivity. Both redox systems, Q10 and DMPC-Q10, are sensitive to the Na + concentration in the electrolyte and mechanistic implications are discussed.