Determination of hydrogen peroxide by using a flow injection system with immobilized peroxidase and long pathlength capillary spectrophotometry |
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Authors: | Alexandros Ch PappasConstantine D Stalikas Yannis Ch FiamegosMiltiades I Karayannis |
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Institution: | Laboratory of Analytical Chemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece |
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Abstract: | The development of a highly sensitive method for the determination of nanomolar concentrations of hydrogen peroxide in the liquid phase is described. This paper demonstrates for the first time a flow injection analysis (FIA) system with immobilized enzyme reactor combined with a total internal reflective cell (a liquid waveguide capillary cell (LWCC)) and spectrophotometric detection, for the development of an improved procedure for the determination of hydrogen peroxide. Moreover, the newly synthesized 4-aminopyrazolone derivative, 4-amino-5-(p-aminophenyl)-1-methyl-2-phenyl-pyrazol-3-one (DAP), is used as a color coupler in its oxidative condensation with the sodium salt of N-ethyl-N-sulphopropylaniline sodium salt (ALPS) which acts as a hydrogen donor. Immobilization of peroxidase is achieved by coupling the periodate-treated enzyme to aminopropyl controlled-pore glass (CPG) beads. The determination of hydrogen peroxide is carried out in a 0.1 M phosphate buffer and the product is monitored at 590 nm with a charge-coupled device (CCD) detector equipped with fiber optics in a fully computerized system. The interference of different species, mainly ionic, was investigated.The method permits detection down to 4 nmol l−1 hydrogen peroxide (signal-to-noise ratio=3). A linear calibration graph was obtained over the range 20-700 nmol l−1. The relative standard deviation (R.S.D.) at 300 nmol l−1 H2O2 is 1.7% (n=7). The method was successfully applied for the determination of hydrogen peroxide in samples from a vat-cleaning process. |
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Keywords: | Hydrogen peroxide Liquid waveguide capillary cell Immobilized peroxidase Flow injection analysis |
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