title: A flow system with zone merging and zone trapping in the main reactor applied to spectrophotometric catalytic determination of cobalt in grasses.
abstract: A flow system with zone merging and zone trapping in the main reactor was proposed. The sample and reagent inserted aliquots merge together and the resulting zone is directed towards a displaceable reactor inside which its most concentrated portion is trapped. After the pre-set TRAP period, the handled sample is released towards detection. A comparison with an analogous flow system exploiting zone stopping revealed the superior characteristics of sampling rate and system operation; moreover, the sample inserted volume plays little influence on sampling rate. The system was applied to the spectrophotometric determination of cobalt in pastures, and enhanced figures of merit (sampling rate=18 h(-1); peak height r.s.d.=0.7%, detection limit=0.046 μg L(-1) Co; reagent consumption=330 μg of Tiron per measurement; 98%<recovery<114%) were estimated.
authors.affiliation: Centre for Nuclear Energy in Agriculture, University of S. Paulo Box 96, Piracicaba 13400-970, Brazil.
authors.forename: Taciana F
authors.initials: TF
authors.lastname: Gomes
authors.forename: Ana C F
authors.initials: AC
authors.lastname: Vida
authors.forename: Milton K
authors.initials: MK
authors.lastname: Sasaki
authors.forename: Claudineia R
authors.initials: CR
authors.lastname: Silva
authors.forename: Valdemir A F
authors.initials: VA
authors.lastname: Barros
authors.forename: Elias A G
authors.initials: EA
authors.lastname: Zagatto
mesh_terms: D014013:1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt / Q000737:chemistry; D002384:Catalysis; D003035:Cobalt / Q000032:analysis*; D006861:Hydrogen Peroxide / Q000737:chemistry; D007202:Indicators and Reagents / Q000737:chemistry; D010084:Oxidation-Reduction; D006109:Poaceae / Q000737:chemistry*; D012972:Sodium Hydroxide / Q000737:chemistry; D013053:Spectrophotometry / Q000379:methods
chemical_list: D007202:Indicators and Reagents; D003035:Cobalt; D014013:1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt; D012972:Sodium Hydroxide; D006861:Hydrogen Peroxide