1. Spectrophotometric method of COD analyzer
Potassium dichromate spectrophotometry is widely used in rapid COD detection and online detection. This method has the advantages of fast measurement speed, short digestion time, less reagent consumption, simple operation and high degree of automation. The disadvantage is that the COD value measurement result is slightly different from the potassium dichromate standard method.
2. Coulometric titration of COD analyzer
Coulometric titration method is suitable for the determination of drinking water, surface water, industrial sewage, domestic sewage and other water quality. It has a good degree of measurement, and the measurement result is consistent with the potassium dichromate standard method. Coulometric titration is a commonly used method for the determination of chemical oxygen demand, with simple operation and fast determination.
3. Potassium dichromate standard method for COD analyzer
COD can be measured with potassium dichromate standard method to obtain an accurate COD value, but the COD potassium dichromate standard method has many shortcomings. The COD potassium dichromate standard method is complicated in operation, requires a long time of heating and refluxing, and the equipment used for heating and refluxing is bulky, which makes it difficult to realize batch measurement. In addition, the COD potassium dichromate standard method requires the use of silver salt, which makes the cost higher.
4. Microwave digestion spectrophotometry of COD analyzer
The microwave digestion photometric method of COD is a new type of COD measurement method. It uses microwave digestion to reduce the time required for digestion, greatly improve the efficiency of digestion, and ensure the reliability of measurement data. According to current research, the microwave digestion photometric method of COD is likely to gradually replace the traditional COD measurement method.
5. UV meter measurement method of COD analyzer
The COD UV meter measurement method is also a relatively late measurement method. It is suitable for colorless and transparent water quality measurement with stable composition. It has the advantages of accurate measurement and low investment cost. However, the use of UV meters to measure COD is restricted by ethanol, organic acids and other non-UV-absorbing substances, so it is difficult to be widely promoted.