title: DoE optimization of a mercury isotope ratio determination method for environmental studies.
abstract: By using the experimental design (DoE) technique, we optimized an analytical method for the determination of mercury isotope ratios by means of cold-vapor multicollector ICP-MS (CV-MC-ICP-MS) to provide absolute Hg isotopic ratio measurements with a suitable internal precision. By running 32 experiments, the influence of mercury and thallium internal standard concentrations, total measuring time and sample flow rate was evaluated. Method was optimized varying Hg concentration between 2 and 20 ng g(-1). The model finds out some correlations within the parameters affect the measurements precision and predicts suitable sample measurement precisions for Hg concentrations from 5 ng g(-1) Hg upwards. The method was successfully applied to samples of Manila clams (Ruditapes philippinarum) coming from the Marano and Grado lagoon (NE Italy), a coastal environment affected by long term mercury contamination mainly due to mining activity. Results show different extents of both mass dependent fractionation (MDF) and mass independent fractionation (MIF) phenomena in clams according to their size and sampling sites in the lagoon. The method is fit for determinations on real samples, allowing for the use of Hg isotopic ratios to study mercury biogeochemical cycles in complex ecosystems.
authors.affiliation: Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Via G. Campi, 103, 41125 Modena, Italy.
authors.forename: Alex
authors.initials: A
authors.lastname: Berni
authors.affiliation: Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Via G. Campi, 103, 41125 Modena, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Baschieri
authors.affiliation: Department of Mathematics and Geosciences, University of Trieste, Via Weiss 2, 34128 Trieste, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Covelli
authors.affiliation: Department of Mathematics and Geosciences, University of Trieste, Via Weiss 2, 34128 Trieste, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Emili
authors.affiliation: Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Via G. Campi, 103, 41125 Modena, Italy. Electronic address: andrea.marchetti@unimore.it.
authors.forename: Andrea
authors.initials: A
authors.lastname: Marchetti
authors.affiliation: Centro Interdipartimentale Grandi Strumenti (CIGS), University of Modena and Reggio Emilia, Via G. Campi 213/A, 41125 Modena, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Manzini
authors.affiliation: National Institute for Environmental Protection and Research (ISPRA), Loc. Brondolo, 30015 Chioggia, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Berto
authors.affiliation: National Institute for Environmental Protection and Research (ISPRA), Loc. Brondolo, 30015 Chioggia, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Rampazzo
mesh_terms: D000818:Animals; D049872:Bivalvia / Q000737:chemistry*; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000032:analysis*; D005163:Factor Analysis, Statistical; D006801:Humans; D008522:Mediterranean Sea; D008628:Mercury / Q000032:analysis*; D008629:Mercury Isotopes; D008906:Mining; D012015:Reference Standards; D013054:Spectrophotometry, Atomic; D013793:Thallium / Q000032:analysis
chemical_list: D004785:Environmental Pollutants; D008629:Mercury Isotopes; D013793:Thallium; D008628:Mercury
keywords: DoE; MDF and MIF Hg fractionation processes; Mercury isotopes; Multi Linear Regression; Multicollector ICP-MS