Aggregates of gold nanoparticles with complexes containing ruthenium as modifiers in carbon paste electrodes

Gold nanoparticles (AuNPs−) were synthesized through the reduction of HAuCl4 with a solution of sodium citrate 1%, getting negatively charged species. [RuIICl(dppb)(bipy)(py)](PF6) and [RuIIICl2(dppb)(phen)](PF6) were also synthesized as monocationic species (Ru+), where dppb = 1,4-bis(diphenylphosphino)butane, bipy = 2,2′-bipyridine, phen = 1,10-phenantroline and py = pyridine. Aggregates of AuNPs− with negatively charged and with a cationic complex containing ruthenium (II) and (III) were obtained by means of electrostatic interactions. The AuNPs− and aggregates (Ru–AuNPs) were analyzed by ultraviolet/visible spectroscopy (UV–Vis), Fourier transform infrared spectroscopy–attenuated total reflectance (FTIR–ATR), nuclear magnetic resonance of phosphorous (31P{1H} NMR), cyclic voltammetry (CV) and field emission scanning electron microscopy (FE-SEM). The AuNPs− and the Ru–AuNPs were used as modifiers in the preparation of carbon paste electrodes and their performance were evaluated by cyclic voltammetry to determination of acetaminophen.

Graphical abstractGold nanoparticles (AuNPs−) were used as modifiers in the preparation of carbon paste electrode (CPE–AuNPs−) and it was used as support to prepare thin solids films with [RuCl(dppb)(bipy)(py)]+ (CPE–AuNPs–Ru). The performances of nude CPE, CPE–AuNPs− and CPE–AuNPs–Ru were evaluated by cyclic voltammetry to determination of acetaminophen. The redox potential reversibility (ΔEp) of acetaminophen with CPE–AuNPs–Ru was improved almost five times when compared with nude CPE.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Aggregates of AuNPs− and Ru+ were obtained by electrostatic interactions. ► Ru–AuNPs were analyzed by electrochemical, spectroscopy and microscopy techniques. ► AuNPs− and Ru–AuNPs were used as modifiers in carbon paste electrodes. ► The electrodes performances were evaluated to determination of acetaminophen.