title: A critical evaluation of a flow-cell based on a liquid core waveguide for chemiluminescence measurements.
abstract: Liquid-core waveguides (LCWs), devices that constrain the emitted radiation minimizing losses during the transport, are an alternative to maximize the amount of detected radiation in luminescence. In this work, the performance of a LCW flow-cell was critically evaluated for chemiluminescence measurements, by using as model the oxidation of luminol by hydrogen peroxide or hypochlorite. An analytical procedure for hypochlorite determination was also developed, with linear response in the range 0.2-3.8 mg/L (2.7-51 micromol/L), a detection limit estimated as 8 microg/L (0.64 micromol/L) at the 99.7% confidence level and luminol consumption of 50 microg/determination. The coefficients of variation were 3.3% and 1.6% for 0.4 and 1.9 mg/L ClO(-), respectively, with a sampling rate of 164 determinations/h. The procedure was applied to the analysis of Dakin's solution samples, yielding results in agreement with those obtained by iodometric titration at the 95% confidence level.
authors.affiliation: Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil.
authors.forename: Mariana A
authors.initials: MA
authors.lastname: Sanchez
authors.forename: Fábio R P
authors.initials: FR
authors.lastname: Rocha
mesh_terms: D005292:Ferricyanides / Q000737:chemistry; D017022:Flow Injection Analysis / Q000295:instrumentation / Q000379:methods*; D006861:Hydrogen Peroxide / Q000032:analysis*; D006997:Hypochlorous Acid / Q000032:analysis*; D049449:Luminescence; D008163:Luminescent Measurements / Q000295:instrumentation / Q000379:methods*; D008165:Luminol / Q000737:chemistry*; D010084:Oxidation-Reduction; D012680:Sensitivity and Specificity; D013997:Time Factors; D017186:Titrimetry / Q000379:methods
chemical_list: D005292:Ferricyanides; D008165:Luminol; D006997:Hypochlorous Acid; D006861:Hydrogen Peroxide