QUANTIFICACAO DE NANOPARTICULAS DE PRATA EM UM PRODUTO FARMACEUTICO POR ESPECTROFOTOMETRIA E POTENCIOMETRIA: UMA PROPOSTA PARA AULAS PRATICAS DE QUIMICA ANALITICA

• Autor(a) principal: Brito,Elen C. P. de
• Data de Publicação: 2021
• Outros Autores: Madalena,Ludmila dos S., Lima,Richard H., Bernardes,Gabriel S., Silva,Luis Antonio da, Alves,Valeria A.
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Química Nova (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422021000100105
• topic: silver vitellinate; silver; spectrophotometry; potentiometry

Spectrophotometry and potentiometry techniques were used to quantify silver in an ophthalmic solution. A standard solution of silver nanoparticles was synthesized, from which an analytical method was developed to quantify silver in the sample. Potentiometric titrations of three samples were made, using an electrochemical cell containing an alternative metallic indicator electrode and an Ag|AgCl double junction reference electrode, connected to a potentiometer. A digital burette containing a standard solution 5.00 x 10-3 mol L-1 NaCl was used. Characterization of the ophthalmic solution by spectrophotometry showed that Ag in this medicine is in the form of nanoparticles. The sample preparation for potentiometric measurements was carried out using a mixture of 50 µL of the ophthalmic solution and 2.00 mL of nitric acid. The average concentrations of Ag obtained were 1.65 ± 0.03% (w/v) by spectrophotometry, and 1.73 ± 0.06% (w/v) by potentiometry. The relative standard deviations were 2% and 4%, respectively. The precision of the measurements obtained by the cited methods showed no significant differences (f test). It was also observed that average silver concentrations obtained by the two methods were not statistically different (t test). Both tests were made at a 95% confidence level.