title: Melted Paraffin Wax as an Innovative Liquid and Solid Extractant for Elemental Analysis by Laser-Induced Breakdown Spectroscopy.
abstract: This work proposes a new development in the use of melted paraffin wax as a new extractant in a procedure designed to aggregate the advantages of liquid phase extraction (extract homogeneity, fast, and efficient transfer, low cost and simplicity) to solid phase extraction. As proof of concept, copper(II) in aqueous samples was converted into a hydrophobic complex of copper(II) diethyldithiocarbamate and subsequently extracted into paraffin wax. Parameters which affect the complexation and extraction (pH, DDTC, and Triton X-100 concentration, vortex agitation time and complexation time) were optimized in a univariate way. The combination of the extraction proposed procedure with laser-induced breakdown spectroscopy allowed the precise copper determination (coefficient of variation = 3.1%, n = 10) and enhanced detectability because of the concentration factor of 18 times. A calibration curve was obtained with a linear range of 0.50-10.00 mg L-1(R2= 0.9990, n = 7), LOD = 0.12 mg L-1, and LOQ = 0.38 mg L-1under optimized conditions. An extraction procedure efficiency of 94% was obtained. The accuracy of the method was confirmed through the analysis of a reference material of human blood serum, by the spike and recovery trials with seawater, tap water, mineral water, and alcoholic beverages and by comparing with those results obtained by graphite furnace atomic absorption spectrometry.
authors.affiliation: CCNH, Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, UFABC , Avenida dos Estados, 5001, Bloco B, 09210-580, Santo André, São Paulo Brazil.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Papai
authors.affiliation: CCNH, Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, UFABC , Avenida dos Estados, 5001, Bloco B, 09210-580, Santo André, São Paulo Brazil.
authors.forename: Roseli Hiromi
authors.initials: RH
authors.lastname: Sato
authors.affiliation: CENA, Centro de Engenharia Nuclear na Agricultura, Universidade de São Paulo , Avenida Centenário 303, 13416-000, Piracicaba, São Paulo Brazil.
authors.forename: Lidiane Cristina
authors.initials: LC
authors.lastname: Nunes
authors.affiliation: CENA, Centro de Engenharia Nuclear na Agricultura, Universidade de São Paulo , Avenida Centenário 303, 13416-000, Piracicaba, São Paulo Brazil.
authors.forename: Francisco José
authors.initials: FJ
authors.lastname: Krug
authors.affiliation: CCNH, Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, UFABC , Avenida dos Estados, 5001, Bloco B, 09210-580, Santo André, São Paulo Brazil.
authors.forename: Ivanise
authors.identifier: 0000-0002-0352-5289
authors.initials: I
authors.lastname: Gaubeur