Microchimica Acta, ( ISI ), Volume (180), No (11), Year (2013-8) , Pages (1029-1036)

Title : ( Miniaturized and green method for determination of chemical oxygen demand using UV-induced oxidation with hydrogen peroxide and single drop microextraction )

Authors: Jeiran Akhoundzadeh , Marta Costas , Isela Lavilla , Mahmod CHamsaz , Carlos Bendicho ,

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Abstract

We report on a green method for the determination of low levels of chemical oxygen demand. It is based on the combination of (a) UV-induced oxidation with hydrogen peroxide, (b) headspace single-drop microextraction with in-drop precipitation, and (c) micro-turbidimetry. The generation of CO2 after photolytic oxidation followed by its sequestration onto a microdrop of barium hydroxide gives rise to a precipitate of barium carbonate which is quantified by turbidimetry. UV-light induced oxidation was studied in the absence and presence of H2O2, ultrasound, and ferrous ion. Determinations of chemical oxygen demand were performed using potassium hydrogen phthalate as a model compound. The optimized method gives a calibration curve that is linear between 3.4 and 20 mg L−1 oxygen. The detection limit was 1.2 mg L−1 of oxygen, and the repeatability (as relative standard deviation) was around 5 %. The method was successfully applied to the determination of chemical oxygen demand in different natural waters and a synthetic wastewater

Keywords

, Chemical oxygen demand . UV/H2O2 oxidation treatment . Headspace single, drop microextraction . Microturbidimetry . Green analytical chemistry