Cd1-xMgxTe semiconductor nanocrystal alloys: Synthesis, preparation of nanocomposites with graphene-based materials, and electrochemical detection of lidocaine and epinephrine

This work describes the synthesis of a glutathione-capped Cd1-xMgxTe semiconductor nanocrystal alloy in aqueous solution. The effects of reaction time and Cd:Mg molar proportion on the spectroscopic and electrochemical properties were optimized. The Cd1-xMgxTe material was found to emit in the visible range (blueish-green to dark pink), with the band gap energy depending both on the Mg:Cd ratio and of the nanocrystal size. The in-situ growth of the nanocrystal alloy on both graphene oxide and reduced graphene oxide leads to partial quenching of the photoluminescence of Cd1-xMgxTe but improves the electrochemical response of the nanocrystals. Carbon paste electrodes (CPE) were modified with the graphene-based materials containing semiconductor nanocrystals, and it is shown that such a modified CPE can be applied to the determination of the local anesthetic lidocaine and the anaphylactic drug epinephrine via differential pulse voltammetry. Each analyte can be determined both individually and in the presence of constant concentrations of the other, best at typical oxidation potentials of 0.25 V and 1.0 V (vs. Ag/AgCl), respectively. In the best cases, the detection limits are 92 nM for lidocaine and 0.95 mu M for epinephrine.