Water quality testing is an important link to ensure the safety of drinking water, protect the environment, and safeguard human health. In the process of water quality testing, the correct selection and use of testing tools and reagents are crucial to ensure the accuracy of the results. This article will introduce the commonly used tools and reagents in water quality testing and provide the correct methods of use.

Water quality testing tools and reagents

pH meter: Used to measure the acidity or alkalinity of water bodies. The correct method of use is to ensure that the instrument is clean and dry, calibrate the instrument before use, and insert the electrode into the water sample and keep it stable for a period of time before reading the value.

Conductivity meter: Used to measure the conductivity of water bodies, which is an effective method to evaluate the content of dissolved salts in water. When using, ensure that the electrodes are clean, calibrate the instrument regularly, and ensure good contact between the electrodes and the water sample before measurement.

Turbidity meter: Used to measure the turbidity of water bodies, i.e., the content of suspended particles in water. The correct method of use is to place the measuring end of the turbidity meter in the water sample, wait for the reading to stabilize, and then read the result.

Dissolved oxygen meter: Used to measure the concentration of dissolved oxygen in water bodies. The correct method of use includes ensuring that the measuring end is fully immersed in the water sample, calibrating the instrument, and operating according to the instructions in the manual.

Colorimeter: Used to measure the color of water bodies, i.e., the depth of color of water. The correct method of use is to immerse the measuring end of the instrument into the water sample and read the colorimeter's color value.

Testing reagents

　　Potassium dichromate solution: Often used to determine the chemical oxygen demand (COD) in water, it reacts with organic matter in water samples to form sulfates and water, and the COD value is calculated based on the amount of potassium dichromate consumed.

Nessler's reagent: Used to determine the ammonia nitrogen content in water, a purple-red compound is formed through a colorimetric reaction, and the depth of color is proportional to the ammonia nitrogen content.

Ammonium molybdate solution: Used to determine the total phosphorus content in water, a blue-green compound is formed through a colorimetric reaction, and the depth of color is proportional to the total phosphorus content.

Carbon tetrachloride: In some specific testing projects, such as the determination of benzene compounds in water, carbon tetrachloride is required as an extracting agent to extract organic matter from water samples and then perform the test.

Points for attention

Correct selection and use of testing tools and reagents: Select appropriate tools and reagents according to the needs of the testing items, and operate strictly according to the instructions.

Instrument calibration: Regular calibration of testing tools is required to ensure their accuracy.

Environmental conditions: Ensure that the testing environment is clean and free from pollution, to avoid interference from external factors on the test results.

Safety protection: When using toxic and harmful reagents, appropriate safety protection measures should be taken, such as wearing protective glasses, gloves, etc.

The correct selection and use of water quality testing tools and reagents can effectively ensure the accuracy and reliability of water quality testing results. At the same time, regular maintenance and calibration of testing tools are also crucial to ensure the accuracy of the results.