title: Arsenic fractionation in agricultural soil using an automated three-step sequential extraction method coupled to hydride generation-atomic fluorescence spectrometry.
abstract: A fully automated modified three-step BCR flow-through sequential extraction method was developed for the fractionation of the arsenic (As) content from agricultural soil based on a multi-syringe flow injection analysis (MSFIA) system coupled to hydride generation-atomic fluorescence spectrometry (HG-AFS). Critical parameters that affect the performance of the automated system were optimized by exploiting a multivariate approach using a Doehlert design. The validation of the flow-based modified-BCR method was carried out by comparison with the conventional BCR method. Thus, the total As content was determined in the following three fractions: fraction 1 (F1), the acid-soluble or interchangeable fraction; fraction 2 (F2), the reducible fraction; and fraction 3 (F3), the oxidizable fraction. The limits of detection (LOD) were 4.0, 3.4, and 23.6 μg L(-1) for F1, F2, and F3, respectively. A wide working concentration range was obtained for the analysis of each fraction, i.e., 0.013-0.800, 0.011-0.900 and 0.079-1.400 mg L(-1) for F1, F2, and F3, respectively. The precision of the automated MSFIA-HG-AFS system, expressed as the relative standard deviation (RSD), was evaluated for a 200 μg L(-1) As standard solution, and RSD values between 5 and 8% were achieved for the three BCR fractions. The new modified three-step BCR flow-based sequential extraction method was satisfactorily applied for arsenic fractionation in real agricultural soil samples from an arsenic-contaminated mining zone to evaluate its extractability. The frequency of analysis of the proposed method was eight times higher than that of the conventional BCR method (6 vs 48 h), and the kinetics of lixiviation were established for each fraction.
authors.affiliation: Universidad Autónoma de Nuevo León, UANL, Facultad de Ciencias Químicas, Cd. Universitaria, San Nicolás de los Garza, Nuevo León, C.P. 66451 Nuevo León, Mexico; Group of Analytical Chemistry, Automation and Environment, University of Balearic Islands, Cra. Valldemossa km 7.5, 07122 Palma de Mallorca, Spain.
authors.forename: J M
authors.initials: JM
authors.lastname: Rosas-Castor
authors.affiliation: Group of Analytical Chemistry, Automation and Environment, University of Balearic Islands, Cra. Valldemossa km 7.5, 07122 Palma de Mallorca, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Portugal
authors.affiliation: Group of Analytical Chemistry, Automation and Environment, University of Balearic Islands, Cra. Valldemossa km 7.5, 07122 Palma de Mallorca, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Ferrer
authors.affiliation: Universidad Autónoma de Nuevo León, UANL, Facultad de Ciencias Químicas, Cd. Universitaria, San Nicolás de los Garza, Nuevo León, C.P. 66451 Nuevo León, Mexico.
authors.forename: J L
authors.initials: JL
authors.lastname: Guzmán-Mar
authors.affiliation: Universidad Autónoma de Nuevo León, UANL, Facultad de Ciencias Químicas, Cd. Universitaria, San Nicolás de los Garza, Nuevo León, C.P. 66451 Nuevo León, Mexico.
authors.forename: A
authors.initials: A
authors.lastname: Hernández-Ramírez
authors.affiliation: Group of Analytical Chemistry, Automation and Environment, University of Balearic Islands, Cra. Valldemossa km 7.5, 07122 Palma de Mallorca, Spain.
authors.forename: V
authors.initials: V
authors.lastname: Cerdà
authors.affiliation: Universidad Autónoma de Nuevo León, UANL, Facultad de Ciencias Químicas, Cd. Universitaria, San Nicolás de los Garza, Nuevo León, C.P. 66451 Nuevo León, Mexico. Electronic address: laura.hinojosary@uanl.edu.mx.
authors.forename: L
authors.initials: L
authors.lastname: Hinojosa-Reyes
mesh_terms: D000383:Agriculture; D001151:Arsenic / Q000032:analysis* / Q000302:isolation & purification; D005591:Chemical Fractionation / Q000295:instrumentation / Q000379:methods*; D004867:Equipment Design; D017022:Flow Injection Analysis / Q000295:instrumentation / Q000379:methods; D057230:Limit of Detection; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis* / Q000302:isolation & purification; D013050:Spectrometry, Fluorescence / Q000295:instrumentation / Q000379:methods; D013054:Spectrophotometry, Atomic / Q000295:instrumentation / Q000379:methods
chemical_list: D012987:Soil; D012989:Soil Pollutants; D001151:Arsenic
keywords: Agricultural soil sample; Automated arsenic fractionation; Multisyringe flow injection analysis; Sequential extraction method