title: Determination of sulfur in crude oil using high-resolution continuum source molecular absorption spectrometry of the SnS molecule in a graphite furnace.
abstract: An analytical method for the determination of sulfur, as the tin mono-sulfide (SnS) molecule, in crude oil using high-resolution continuum source graphite furnace molecular absorption spectrometry (HR-CS GF MAS) has been developed. The molecular absorbance of the SnS has been measured using the wavelength at 271.624 nm and the crude oil samples were prepared as micro-emulsions due to their high viscosity. Several chemical modifiers (Ir, Pd, Ru, Zr) were tested and palladium was chosen, because it exhibited the best performance. The heating program was optimized by comparing the pyrolysis and vaporization curves obtained for an aqueous sulfur standard and a micro-emulsion of a crude oil certified reference material (CRM). The optimum pyrolysis and vaporization temperatures were found to be 600 and 2000°C, respectively. The limit of detection and the characteristic mass using micro-emulsion analysis of crude oil samples were 5.8 and 13.3 ng S. Accuracy and precision of the method has been evaluated using two crude oil CRM (NIST 2721 and NIST 2722), showing good agreement with the informed or certified values.
authors.affiliation: Departamento de Química, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC, Brazil.
authors.forename: Heloisa R
authors.initials: HR
authors.lastname: Cadorim
authors.affiliation: Departamento de Química, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC, Brazil.
authors.forename: Éderson R
authors.initials: ÉR
authors.lastname: Pereira
authors.affiliation: Departamento de Química, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC, Brazil.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Carasek
authors.affiliation: Departamento de Química, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC, Brazil; Instituto Nacional de Ciência e Tecnologia (INCT) do CNPq - INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA, Brazil. Electronic address: w.bernardo@terra.com.br.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Welz
authors.affiliation: Instituto Nacional de Ciência e Tecnologia (INCT) do CNPq - INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA, Brazil.
authors.forename: Jailson B
authors.initials: JB
authors.lastname: de Andrade
keywords: Crude oil; HR-CS GF MAS; Molecular absorption; Sulfur determination; Tin sulfide