IN VITRO Cr(VI) SPECIATION IN SYNTHETIC SALIVA AFTER RELEASING FROM ORTHODONTIC BRACKETS USING SILICA-APTES SEPARATION AND GF AAS DETERMINATION
AUTOR(ES)
Luz, Maciel S., Souza, Alexandre L., Haddad, Ana C. S. S., Tartomano, André, Oliveira, Pedro V.
FONTE
Quím. Nova
DATA DE PUBLICAÇÃO
2016-09
RESUMO
A method for Cr(VI) speciation in synthetic saliva after releasing from orthodontic brackets, using silica nanoparticles organofunctionalized with (3-aminopropyl)triethoxysilane (APTES) for Cr(III)/Cr(VI) separation and GF AAS determination is proposed. Under the optimized conditions, Cr(VI) speciation was performed using 150 mg of silica organofunctionalized with 2.0% (v v-1) of APTES at pH 8. It was observed different sensitivity when calibrations of GF AAS were performed using Cr(III) or Cr(VI) as standard solutions. Consequently, calibrations using stoichiometric mixtures (Cr(III) + Cr(VI)) were used for total Cr determination and calibration using Cr(VI) was used only for the determination of this specie. The reliability of the proposed silica-APTES separation procedure and GF AAS determination was checked by addition of both species in synthetic saliva. Recoveries ranging from 97 to 110% were obtained. The repeatability, based on the relative standard deviation (RSD) inter days was less than 6%. A corrosion test was carried out on 20 orthodontic brackets from two different models, after immersion in synthetic saliva (pH=6.0) at 37 °C with agitation (125 rpm) for 24 h. It was observed that about 40% of the total chromium released from the analyzed orthodontic brackets was Cr(VI).
Documentos Relacionados
- Indirect spectrophotometric method for determination of captopril using Cr(VI) and diphenylcarbazide
- Evaluation of analytical procedures for determination of Cr(III and Cr(VI) in solid samples.
- Cr(VI) Reduction by Sulfidogenic and Nonsulfidogenic Microbial Consortia
- Estudo da redução de Cr(VI) por acido nitrico
- Remoção de Cr(VI) de soluções aquosas utilizando argilas anionicas tipo hidrotalcita