title: Cobalt internal standard for Ni to assist the simultaneous determination of Mo and Ni in plant materials by high-resolution continuum source graphite furnace atomic absorption spectrometry employing direct solid sample analysis.
abstract: A new method is proposed for the simultaneous determination of Mo and Ni in plant materials by high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GFAAS), employing direct solid sample analysis (DSS) and internal standardization (IS). Cobalt was used as internal standard to minimize matrix effects during Ni determinations, enabling the use of aqueous standards for calibration. Correlation coefficients for the calibration curves were typically better than 0.9937. The performance of the method was checked by analysis of six plant certified reference materials, and the results for Mo and Ni were in agreement with the certified values (95% confidence level, t-test). Analysis was made of different types of plant materials used as renewable sources of energy, including sugarcane leaves, banana tree fiber, soybean straw, coffee pods, orange bagasse, peanut hulls, and sugarcane bagasse. The concentrations found for Mo and Ni ranged from 0.08 to 0.63 ng mg(-1) and from 0.41 to 6.92 ng mg(-1), respectively. Precision (RSD) varied from 2.1% to 11% for Mo and from 3.7% to 10% for Ni. Limits of quantification of 0.055 and 0.074 ng were obtained for Mo and Ni, respectively.
authors.affiliation: São Paulo State University-Unesp, Analytical Chemistry Department, P.O. Box 355, 14801-970 Araraquara, SP, Brazil.
authors.forename: Diego Victor
authors.initials: DV
authors.lastname: de Babos
authors.affiliation: São Paulo State University-Unesp, Analytical Chemistry Department, P.O. Box 355, 14801-970 Araraquara, SP, Brazil.
authors.forename: Marcos André
authors.initials: MA
authors.lastname: Bechlin
authors.affiliation: São Paulo State University-Unesp, Analytical Chemistry Department, P.O. Box 355, 14801-970 Araraquara, SP, Brazil.
authors.forename: Ariane Isis
authors.initials: AI
authors.lastname: Barros
authors.affiliation: São Paulo State University-Unesp, Analytical Chemistry Department, P.O. Box 355, 14801-970 Araraquara, SP, Brazil.
authors.forename: Edilene Cristina
authors.initials: EC
authors.lastname: Ferreira
authors.affiliation: São Paulo State University-Unesp, Analytical Chemistry Department, P.O. Box 355, 14801-970 Araraquara, SP, Brazil. Electronic address: anchieta@iq.unesp.br.
authors.forename: José Anchieta
authors.initials: JA
authors.lastname: Gomes Neto
authors.affiliation: University of São Paulo-USP, FFCLRP, Department of Chemistry, 14040-901, Ribeirão Preto, SP, Brazil.
authors.forename: Silvana Ruella
authors.initials: SR
authors.lastname: de Oliveira
mesh_terms: D002138:Calibration; D003035:Cobalt / Q000032:analysis; D006108:Graphite / Q000737:chemistry*; D006358:Hot Temperature; D008982:Molybdenum / Q000032:analysis*; D009532:Nickel / Q000032:analysis*; D018515:Plant Leaves / Q000737:chemistry; D010944:Plants / Q000737:chemistry*; D012015:Reference Standards; D013054:Spectrophotometry, Atomic / Q000592:standards*; D013997:Time Factors
chemical_list: D003035:Cobalt; D006108:Graphite; D009532:Nickel; D008982:Molybdenum
keywords: Direct solid sample analysis; High-resolution continuum source graphite furnace atomic absorption spectrometry; Internal standardization; Micronutrients; Molybdenum; Nickel