What are the methods for measuring residual chlorine?

Colorimetry (DPD colorimetry)

Total chlorine (sum of residual chlorine and ammonium chloride): determined by adding potassium iodide in the reaction, the ammonium chloride in the sample oxidizes the potassium iodide to iodine, and together with the residual chlorine (residual chlorine analyzer) oxidizes the DPD indicator, The oxide is purple-red at pH 5.1. At this point, potassium iodide-containing buffer is used to maintain the pH of the reaction and provide the potassium iodide required for the reaction.

1. Test items: dozens of test parameters can be expanded and customized according to needs.

2. Operating system: The guided operating system. The interface is simple and easy to understand and guides the user to complete the operation quickly and accurately.

3. It has a power-off protection function and a one-key reset function to prevent data loss.

4. Intelligent detection: Standard measurement and continuous measurement can be switched arbitrarily, reducing repeated measurement steps and improving detection efficiency.

5. Safe operation: The integrated tube for digestion and colorimetry is adopted to reduce the steps of removing the medicine, and the detection is simple, fast, and safe.

6. Data transmission: Support USB, network port, Bluetooth, and PC or printer for data transmission.

7. Data storage: A standard working curve and 96 user-defined items can store 4000 test data.

Electrode method (aka amperometric method)

The online analog control system instrument has the advantages of simple operation and safe use, a variety of temperature compensation methods are optional, and strong anti-interference ability. It can perform single-point online detection of dissolved oxygen, pH/ORP, conductivity, residual chlorine and total chlorine in water bodies, and is widely used in industrial process detection and control such as drinking water, sewage, scientific research, printing and dyeing, electroplating, and ultrapure water.

In conclusion:

The above is the main method for the determination of residual chlorine. The data obtained by the colorimetric method has higher precision and is very reliable, but it can only perform artificial residual chlorine and total chlorine analysis on water samples. Test, continuous measurement and measurement are not possible, and the test cost is low. The electrode method continuously feedbacks the residual chlorine in the flowing water, which can form linear real-time data. Compared with the colorimetric method, the consumables are less, and the operation steps are relatively simple, but the accuracy is not as high as that of the colorimetric method. It is mainly used in pools. Continuous monitoring and analysis of the station.