title: Spectrophotometric determination of gallium in biological materials at nanogram levels with thiocarbohydrazone derivatives.
abstract: Two spectrophotometric methods for the determination of micrograms of gallium in biological materials are described. Proposed chromogenic reagents are 1-(phenyl-2-pyridyl)carbylidene-5-resorcylidenethiocarbohydrazo ne (PPRT) and 1-(phenyl-2-pyridyl)carbylidene-5-salicylidene thiocarbohydrazone (PPST), which form yellow 1:2 (gallium: reagent) complexes. Reactions develop at pH 4.5-6.0 in a 52% (v/v) DMF solution for PPST and at pH 4.0-7.5 in a 48% (v/v) ethanol solution for PPRT. Optimum conditions for reactions are discussed for molar absorptivity values of 59000 and 65000 l.mol-1.cm-1 for PPST and PPRT, respectively. Detection limits are 8 ng/ml for PPST and 5 ng/ml for PPRT, and the range of application is 20-800 ng/ml of gallium. Advantages of the methods include simplicity, high sensitivity and relative selectivity, allowing their application in the determination of gallium in spiked biological samples, using a previous extraction step in n-butyl acetate to avoid interference from Fe(III) and Cu(II).
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, University of Seville, Spain.
authors.forename: R B
authors.initials: RB
authors.lastname: Lucena
authors.forename: E
authors.initials: E
authors.lastname: Morales
authors.forename: J L
authors.initials: JL
authors.lastname: Gomez-Ariza
mesh_terms: D000818:Animals; D001923:Brain Chemistry; D002417:Cattle; D005708:Gallium / Q000032:analysis*; D006835:Hydrazones; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D007668:Kidney / Q000737:chemistry; D008099:Liver / Q000737:chemistry; D010783:Photometry
chemical_list: D006835:Hydrazones; D007202:Indicators and Reagents; C088743:1-(phenyl-2-pyridyl)carbylidene-5-resorcylidenethiocarbohydrazone; C088744:1-(phenyl-2-pyridyl)carbylidene-5-salicylidenethiocarbohydrazone; D005708:Gallium