Patent ID: 9207204
Filing Date: 2015-12-08
Classification: G01N

Abstract:
1. A method for determining information concerning the presence of ingredients with an oxygen demand in a liquid sample by means of electrochemical oxidation of ingredients of the liquid sample, comprising the steps of: providing a boron doped, diamond electrode; placing the boron doped, diamond electrode in the sample; providing a reference electrode; placing the reference electrode in the sample; permitting oxidation of the ingredients of the liquid sample on the boron doped, diamond electrode, at a controlled potential of the boron doped diamond electrode; ascertaining from electrical current flowing via the boron doped, diamond electrode connected as a working electrode of a three electrode circuit, the quantity of material converted per unit time on the working electrode; and ascertaining from the quantity of the material converted per unit time on the working electrode the chemical oxygen demand of the liquid sample, wherein: the boron doped, diamond electrode is operated sequentially at least two different, predetermined potentials, and at each predetermined potential a measured value of the electrical current flowing through the liquid sample at the predetermined potential is measured; the electrical current measured values are placed in a predetermined relationship to one another; the quotient or difference or a measurement curve of the electrical current, measured values is formed, as a function of the predetermined potentials; from the relationship placing, a chemical oxygen demand (COD) in the liquid sample is derived; oxidation products formed on the boron doped, diamond electrode are quantitatively detected: and the concentration of the oxidation products formed on the boron doped, diamond electrode is ascertained by determining redox potential by ascertaining a potential occurring at an additional metal electrode, which is immered into the liquid sample.