Dissolved oxygen analyzer is based on the principle of electrochemistry, which means that oxidation-reduction reactions will occur on two different metal electrodes in an oxygen-containing electrolyte solution. It is called a dissolved oxygen analyzer, and oxygen is reduced by the working electrode through the barrier, generating a diffusion current inversely proportional to the oxygen concentration. After measuring this current, the concentration of dissolved oxygen in water is lost.

Depending on the concentration, the barrier electrode can be divided into two types: polarographic and galvanic. The polarographic barrier electrode uses silver silver chloride as the counter electrode, with potassium chloride as the electrolyte outside the electrode, and polyethylene and polytetrafluoroethylene films with a thickness of 25-50 μ m inside the electrode. The film blocks the exchange of liquid between the electrode surface and inside, allowing dissolved oxygen in water to enter the outside of the electrode. The voltage between the two electrodes is controlled at 0.5-0.8V, and the diffusion current measured by the internal circuit indicates the concentration of dissolved oxygen. The primary battery uses silver as the anode electrode and lead as the cathode electrode. The anode electrode and silver electrode are immersed in a potassium hydroxide electrolytic cell to form two half cells, with the outer layer sealed with a thin film. Dissolved oxygen is reduced at the anode, causing a diffusion current. The concentration of dissolved oxygen can be determined by measuring the diffusion current.

Meanwhile, dissolved oxygen meters usually play an important role in the calibration of online dissolved oxygen sensors in breweries. Manual calibration between dissolved oxygen sensors and portable dissolved oxygen meters during the process can easily encounter problems. Calibration is crucial to ensure that online dissolved oxygen sensors can provide reliable measurement data. There are different dissolved oxygen measurement technologies available in the current market, and breweries may use online sensors from one technology while using another for portable dissolved oxygen measurement. The risk of doing so is that the measurement lacks comparability or consistency.

How does the tested solution not react with the salt bridge component?

If the tested solution contains soluble silver salts, monovalent mercury salts, or thallium Yan, potassium chloride solution cannot be used in the salt bridge, and saturated potassium nitrate or nitrate An solution should be used to obtain satisfactory measurement results. For non-aqueous solutions, a methanol solution of sodium iodide and an ethanol solution of potassium thiocyanate should be used as intermediate solutions.

In short, the components in the salt bridge solution should not undergo precipitation, oxidation-reduction reactions, or other phenomena with the measured solution, otherwise it will interfere with the determination of electromotive force.