Electrochemical Study and Direct Determination of Adenosine-5′-Monophosphate Coupled to 6-Thioguanosine and a Glassy Carbon Modified Electrode with Gold Nanoparticles

The direct accumulation of 6-thioguanosine (6-TG) and its electrochemistry has been studied by cyclic voltammetry in different conditions physical and chemical. In a first moment the surface of electrode was modified with gold nanoparticles. This modification was realized by electrodeposition on the active surface of a glassy carbon electrode with a HAuCl4 solution. The nucleotide 6-thioguanosine was deposited in this gold nanoparticles monolayer. The study of accumulation of other nucleotide, adenosine 5 '-monophosphate (AMP), was realized by the direct reaction with 6-TG deposited. The conditions of the reaction and its electrochemical response were tested to fix the ideal conditions of its determination. The ideal conditions of formation of the monolayer and its electrochemical response were studied; the possibility of preconcentration of 6-TG nucleotide in gold nanoparticles, the possibility of catalysis and limits of identification and quantification were also determined. The method proposed can be applied in direct determination of oligonucleotides. In this respect we applied it in the determination of AMP in a commercial product of infantile nutrition.