Simple operation process of ammonia nitrogen reagent

Concentration prediction:Before testing the water sample, first predict the ammonia nitrogen value of the water sample, and select the operation steps corresponding to the range, e.g., predict the ammonia nitrogen concentration value to be 0-5mg/L, you need to select the operation step of 0-5mg/L range; If the ammonia concentration is predicted to be 5-50mg/L, the procedure of the 5-50mg/L range is selected.

Remark:If there is insoluble matter in the water sample before testing, it needs to be filtered before measurement; After the color development is completed, if there is an insoluble substance generated, it means that there are interferences in the waterThe water sample needs to be diluted before measurement, if the dilution cannot be solved, the water sample needs to be distilled and other treatment methods (refer to HJ535-2009 for details).

1. When the predicted value is in the range of 0 0- -L 5mg/L

If ammonia nitrogen is present, the water sample is yellow-brown, and the darker the color, the higher the concentration of ammonia nitrogen. Analytical procedure: ammonia nitrogen L; Watch out for overrange tips!

2. When the predicted value is in the range of 5 5--L 50mg/L

If ammonia nitrogen is present, the water sample is yellow-brown, and the darker the color, the higher the concentration of ammonia nitrogen. Analytical procedure: ammonia nitrogen H; Watch out for overrange tips!

3. When the predicted value exceeds 5 50 0 mgL /L

The water sample needs to be diluted to the corresponding concentration value in sections 1-2 above, and then operated according to the corresponding range, and the determination result is multiplied by the dilution factor.

4. Test steps on the computer

5. Precautions

◆ If there is ammonia nitrogen, the water sample shows yellow-brown, and the darker the color, the higher the concentration value of ammonia nitrogen.

◆ Pay attention to cross-contamination, use different measuring utensils for different liquids (pay attention to changing the tip when using a pipette).

◆ Use appropriate pipetting tools to take liquids, and large range measuring tools cannot measure small volumes of water samples, such as: 5mL pipettes cannot be used to remove 2mL and below liquidsFor liquids less than or equal to 2mL, it is recommended to pipette twice with a 1mL pipette.

◆ When using a pipette, it is necessary to calibrate the pipette frequently (it is recommended to do so once a week), and pay attention to replacing the tip during use.

6. Interfering substances