title: Sensitivity enhancement of liquid chromatographic-direct chemiluminescence detection by on-line post-column solvent mediated pre-oxidative chemiluminescence.
abstract: The compatibility of liquid chromatography solvents with oxidizing reagents frequently employed in direct chemiluminescence reactions is examined in this study. Various oxidizing reagents were examined for their response in hydro-organic and micellar mobile phases in both isocratic and gradient elution modes. Mild oxidants like hydrogen peroxide, periodate, cerium and hypochlorite were found to be completely compatible with common reversed phase HPLC solvents posing as no threat to the detection procedure. On the other hand, stronger oxidants like acidic permanganate were found to oxidize organic solvents towards the production of an intense light signal. Although several analytical applications can emerge from this finding, the conjunction of this system with reversed phase HPLC is impractical owing to a significant baseline increase which deteriorates the sensitivity of the analysis. A convenient solution to this problem is proposed based on the regulated on-line post-column pre-oxidation of the organic solvent (SPOC) with mild oxidants that have no influence on the final signal. The analytical utility of this new approach in the determination of organic compounds after chromatographic separation is demonstrated.
authors.affiliation: Laboratory of Analytical Chemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece.
authors.forename: George Z
authors.initials: GZ
authors.lastname: Tsogas
authors.forename: Dimosthenis L
authors.initials: DL
authors.lastname: Giokas
authors.forename: Athanasios G
authors.initials: AG
authors.lastname: Vlessidis
authors.forename: Nicholaos P
authors.initials: NP
authors.lastname: Evmiridis
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D007700:Kinetics; D008163:Luminescent Measurements; D010084:Oxidation-Reduction; D012680:Sensitivity and Specificity; D012997:Solvents / Q000737:chemistry*
chemical_list: D012997:Solvents