In vitro CR (VI) speciation in synthetic saliva after releasing from orthodontic brackets using sílica-aptes separation and GF AAS determinations

Abstract:

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 silicaAPTES 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).


Reference:
LUZ, Maciel Santos; SOUZA, Alexandre L.; HADDAD, Ana C.C.; TORTOMANI, André; OLIVEIRA, Pedro V. In vitro CR (VI) speciation in synthetic saliva after releasing from orthodontic brackets using sílica-aptes separation and GF AAS determinations. Química Nova, v.39,  n.8, 951-955, 2016.

Access to the article on the site:
http://dx.doi.org/10.21577/0100-4042.20160129

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