title: Employment of electrochemically synthesized TGA-CdSe quantum dots for Cr(3+) determination in vitamin supplements.
abstract: The fluorescence quenching of TGA-CdSe quantum dots (QDs) was used for Cr(3+) quantification in vitamin supplements. The QD was electrochemically synthesized, demonstrating high reproducibility with control of particle size, thus making it a clean method, without the presence of reducing agents. Under ideal conditions, with the fluorescence band at 551 nm (excitation 365 nm), the maximum fluorescence quenching was observed at pH 4.0, with a time of 200 s for each data acquisition. Under optimum experimental conditions, linear quenching was observed for Cr(3+) in the range of 25.0-325.0 ng L(-1) (R=0.9996, n=6), a limit of detection of 5.67 ng L(-1), and relative standard deviation of 4.43% (n=10). The recovery test for Cr(3+) quantification in vitamin supplements presented results from 82% to 98%. These Cr(3+) determination results were compared to the same vitamin supplement sample using flame atomic absortion spectrometry (FAAS) method, and no significant differences were observed at 95% confidence level.
authors.affiliation: Departamento de Química, Universidade Federal Rural de Pernambuco, Rua Dom Manuel de Medeiros, S/N, Dois Irmãos, 52171-900 Recife, PE, Brasil; Departamento de Química Fundamental, Universidade Federal de Pernambuco, Av. Jornalista Aníbal Fernandes, s/n-Cidade Universitária, 50740-560 Recife, PE, Brasil.
authors.forename: Gustavo C S
authors.initials: GC
authors.lastname: de Souza
authors.affiliation: Departamento de Química, Universidade Federal Rural de Pernambuco, Rua Dom Manuel de Medeiros, S/N, Dois Irmãos, 52171-900 Recife, PE, Brasil.
authors.forename: Éden E A
authors.initials: ÉE
authors.lastname: de Santana
authors.affiliation: Departamento de Química Fundamental, Universidade Federal de Pernambuco, Av. Jornalista Aníbal Fernandes, s/n-Cidade Universitária, 50740-560 Recife, PE, Brasil; Instituto Federal de Alagoas, Campus Coruripe, 57035-000 Maceió, AL, Brasil.
authors.forename: Paulo A B
authors.initials: PA
authors.lastname: da Silva
authors.affiliation: Departamento de Química Fundamental, Universidade Federal de Pernambuco, Av. Jornalista Aníbal Fernandes, s/n-Cidade Universitária, 50740-560 Recife, PE, Brasil.
authors.forename: Denilson V
authors.initials: DV
authors.lastname: Freitas
authors.affiliation: Departamento de Química Fundamental, Universidade Federal de Pernambuco, Av. Jornalista Aníbal Fernandes, s/n-Cidade Universitária, 50740-560 Recife, PE, Brasil.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Navarro
authors.affiliation: Departamento de Química Fundamental, Universidade Federal de Pernambuco, Av. Jornalista Aníbal Fernandes, s/n-Cidade Universitária, 50740-560 Recife, PE, Brasil.
authors.forename: Ana Paula S
authors.initials: AP
authors.lastname: Paim
authors.affiliation: Departamento de Química, Universidade Federal Rural de Pernambuco, Rua Dom Manuel de Medeiros, S/N, Dois Irmãos, 52171-900 Recife, PE, Brasil. Electronic address: aflavora@dq.ufrpe.br.
authors.forename: André F
authors.initials: AF
authors.lastname: Lavorante
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry*; D002857:Chromium / Q000032:analysis* / Q000737:chemistry; D019587:Dietary Supplements / Q000032:analysis*; D055664:Electrochemical Techniques; D005456:Fluorescent Dyes / Q000737:chemistry; D045663:Quantum Dots / Q000737:chemistry*; D018036:Selenium Compounds / Q000737:chemistry*; D013864:Thioglycolates / Q000737:chemistry*; D014815:Vitamins / Q000032:analysis*
chemical_list: D019187:Cadmium Compounds; D005456:Fluorescent Dyes; D018036:Selenium Compounds; D013864:Thioglycolates; D014815:Vitamins; D002857:Chromium; C017487:2-mercaptoacetate; C058667:cadmium selenide
keywords: CdSe quantum dots; Chromium ion (III); Electrochemical synthesis; Vitamin supplements