IN VITRO Cr(VI) SPECIATION IN SYNTHETIC SALIVA AFTER RELEASING FROM ORTHODONTIC BRACKETS USING SILICA-APTES SEPARATION AND GF AAS DETERMINATION

Química Nova

Haddad, Ana C. S. S.¹  Instituto de Pesquisa Tecnológica do Estado de São Paulo, São Paulo, Brazil¹  Luz, Maciel S.¹  Oliveira, Pedro V.¹  Tartomano, André¹  Universidade de São Paulo, São Paulo, Brazil¹  Souza, Alexandre L.¹ 

关键词:  speciation;    chromium;    Cr(VI);    saliva;    brackets;    GF AAS;   

DOI  :  10.21577/0100-4042.20160129

学科分类：化学（综合）

来源: Sociedade Brasileira de Quimica

【 摘 要 】

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).

【 授权许可】

Unknown