RESUMO
A sensitive solid-state electrochemiluminescence (ECL) electrode for L-cysteine was developed based on depositing layers of a hybrid nanocomposite of polypyrrole-dodecyl benzene sulfate-sodium perchlorate-sodium carbonate-gadolinium (PPy-Gd2O3) on a platinum substrate. The presence of the Gd2O3 nanoparticle layer improved the ECL signal, and under optimum conditions, a linear relationship was observed between the signal and the logarithm of L-cysteine concentration from 1.0 × 10-13 to 1.0 × 10-6 M (R2 = 0.9937). At the emission wavelength around 425 nm , at which the analytical signal was measured, the electrode showed an RSD of less than 4% and a low detection limit of 4.2 × 10-14 M. The results proved to be reproducible and stable, and the electrode was applicable in the determination of L-cysteine in biological fluids with recoveries from 94.0-107%. Graphical abstract The results of this research indicated that the weak ECL of luminol is greatly improved by traces of L-cysteine on a solid-state platinum electrode coated with polypyrrole and gadolinium oxide nanoparticles (NPs) and have hence been effectively used in the analysis of L-cysteine in plasma and saliva.
Assuntos
Cisteína/sangue , Gadolínio/química , Nanocompostos/química , Polímeros/química , Pirróis/química , Cisteína/química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Humanos , Limite de Detecção , Substâncias Luminescentes/química , Medições Luminescentes/métodos , Luminol/química , Reprodutibilidade dos Testes , Saliva/química , EstereoisomerismoRESUMO
The anion-exchange characteristics of 27 elements toward the strongly basic anion-exchange resin Amberlite CG-400 in media containing aqueous formic acid and mixtures of formic acid with sodium formate, hydrochloric acid, sodium nitrite, acetone and methanol have been investigated. Possible separations are described and discussed. The quantitative separations achieved are Sr-La, Zn-Cd-Hg, and Ni-Fe.
