title: Effect of organic solvents in the on-line thermal lens spectrometric detection of chromium(III) and chromium(VI) after ion chromatographic separation.
abstract: The effect of methanol, acetone and acetonitrile on the sensitivity, selectivity and the detection limits (LODs) of the determination of chromium species by ion chromatography was investigated. A collinear dual-beam thermal lens spectrometer was used for the direct detection of chromium complexes [pre-column derivatized Cr(III)-pyridine-2,6-dicarboxylic acid, and post-column derivatized Cr(VI)-1,5-diphenylcarbazide] following the ion chromatographic separation on a Dionex HPIC-CS5A solvent compatible column. Different amounts of organic solvents were added directly to the eluent (up to 30%) and to the post-column reagent (up to 60%) to improve the thermooptical properties of the solvents. Consequently, the sensitivity of the technique was increased by a factor of 2-3 and LODs of 0.1 and 10 microg dm(-3) were achieved for Cr(VI) and Cr(III), respectively, when the eluent reaching the detector contained 30% of acetonitrile. The addition of organic solvents also resulted in significant changes in retention times, which improved the Cr(III)/Cr(VI) separation.
authors.affiliation: Laboratory of Environmental Research, Nova Gorica Polytechnic, Slovenia.
authors.forename: M
authors.initials: M
authors.lastname: Sikovec
authors.forename: M
authors.initials: M
authors.lastname: Franko
authors.forename: M
authors.initials: M
authors.lastname: Novic
authors.forename: M
authors.initials: M
authors.lastname: Veber
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D002857:Chromium / Q000032:analysis*; D009930:Organic Chemicals / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry*; D013057:Spectrum Analysis / Q000379:methods*
chemical_list: D009930:Organic Chemicals; D012997:Solvents; D002857:Chromium