title: Flow injection method for the determination of silver concentration in drinking water for spacecrafts.
abstract: A flow injection method has been developed for determination of silver. The method is based on a reduction reaction with sodium borohydride which leads to the formation of a colloidal species which is monitored at a wavelength of 390 nm. The reaction variables flow rate, sodium borohydride concentration and pH, which affect sensitivity, were investigated and their effects were established using a two-levels, three-factor experimental design. Further optimization of manifold variables (reaction coil and injection volume) allowed us to determine silver in the range 0.050-5.0 mg L(-1) with a minimum detectable concentration of 0.050 mg L(-1). Silver is added, as biocide, to drinking water for spacecrafts. The chemical species of silver, present in this kind of sample, were characterized by a procedure based on the selective retention of Ag(+) onto a 2.2.2. cryptand based substrate followed by determination of the non-bound and bound (after elution) Ag(+) by the FIA method. The method optimized was applied to a drinking water sample provided for the launch with the Automated Transfer Vehicle (ATV) module Jule Verne to the International Space Station (March 9, 2008).
authors.affiliation: Department of Analytical Chemistry, University of Torino, Via P. Giuria 5, 10125 Torino, Italy. mariaconcetta.bruzzoniti@unito.it
authors.forename: Maria Concetta
authors.initials: MC
authors.lastname: Bruzzoniti
authors.forename: Dorota Korte
authors.initials: DK
authors.lastname: Kobylinska
authors.forename: Mladen
authors.initials: M
authors.lastname: Franko
authors.forename: Corrado
authors.initials: C
authors.lastname: Sarzanini
mesh_terms: D001894:Borohydrides / Q000737:chemistry; D017022:Flow Injection Analysis / Q000379:methods*; D012834:Silver / Q000032:analysis*; D018531:Spacecraft; D013056:Spectrophotometry, Ultraviolet; D014867:Water / Q000737:chemistry*
chemical_list: D001894:Borohydrides; D014867:Water; D012834:Silver; C025364:sodium borohydride