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Determination of Se(IV) concentration via cathodic stripping voltammetry in the presence of Cu(II) ions and ammonium diethyl dithiophosphate.
Merino, Ignacio E; Stegmann, Edgardo; Aliaga, Margarita E; Gomez, Marisol; Arancibia, Verónica; Rojas Romo, Carlos.
Afiliación
  • Merino IE; Pontificia Universidad Católica de Chile, Chemistry Faculty, Vicuña Mackenna 4860, Santiago, 7820436, Chile.
  • Stegmann E; Pontificia Universidad Católica de Chile, Chemistry Faculty, Vicuña Mackenna 4860, Santiago, 7820436, Chile.
  • Aliaga ME; Pontificia Universidad Católica de Chile, Chemistry Faculty, Vicuña Mackenna 4860, Santiago, 7820436, Chile.
  • Gomez M; Universidad Bernardo OHiggins, Escuela de Obstetricia y Puericultura and Centro Integrativo de Biología y Química Aplicada (CIBQA), General Gana 1702, Santiago, 8370993, Chile.
  • Arancibia V; Pontificia Universidad Católica de Chile, Chemistry Faculty, Vicuña Mackenna 4860, Santiago, 7820436, Chile. Electronic address: darancim@uc.cl.
  • Rojas Romo C; Pontificia Universidad Católica de Chile, Chemistry Faculty, Vicuña Mackenna 4860, Santiago, 7820436, Chile. Electronic address: crrojas2@uc.cl.
Anal Chim Acta ; 1048: 22-30, 2019 Feb 07.
Article en En | MEDLINE | ID: mdl-30598153
ABSTRACT
The development of a methodology for the determination of Se(IV) concentration via cathodic stripping voltammetry is described in this work. The methodology is based on the formation of copper selenide (Cu2Se), whose reduction signal at -0.60 V has been used as an analytical response to quantify the Se(IV) concentration in solution. The novelty of our methodology is the study of this system in the presence of a ligand such as ammonium diethyl dithiophosphate (ADTTP), which forms complexes with Cu(II) and Se(IV). The results showed that the presence of ADTTP plays an important role, increasing the sensitivity of the determination by almost a factor of two compared with the methodology in the absence of the ligand. The optimized conditions were pH 1.6 (phosphoric acid, 2.0 × 10-2 mol L-1), CCu(II) = 1.5 mg L-1, CADTTP = 2.0 µmol L-1, Eacc = -0.40 V and tacc = 45 s. The detection and the quantification limits obtained were 0.065 and 0.21 µg L-1, respectively, and linearity was maintained up to 4.0 µg L-1 of Se(IV). The sensitivity was 10.26 nA L µg-1. On the other hand, the relative standard deviation for 15 replicate measurements at 1.0 µg L-1 of Se(IV) was 1.6%. The usefulness of the method was evaluated by determining Se(IV) in two certified reference materials (TMDW and TM-28.4) with relative errors of less than 2.0%. The proposed method was successfully applied to the determination of Se(IV) in spiked tap water and in a liquid pharmaceutical formulation with satisfactory results. The developed methodology presents a low detection limit, good repeatability, selectivity and linear range. Furthermore, the sensibility of the method was achieved by applying a short accumulation time (45 s).
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Selenio / Organotiofosfatos / Cobre / Técnicas Electroquímicas Idioma: En Revista: Anal Chim Acta Año: 2019 Tipo del documento: Article País de afiliación: Chile

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Selenio / Organotiofosfatos / Cobre / Técnicas Electroquímicas Idioma: En Revista: Anal Chim Acta Año: 2019 Tipo del documento: Article País de afiliación: Chile