10 precautions for the use of COD rapid analyzer

A brief analysis of 10 precautions for using COD rapid analyzer: The COD rapid analyzer consists of a COD host and a digester, and has functions such as automatic temperature control, timing, zero adjustments, linear regression, curve storage and data printing. Generally, open-tube reflux heating digestion or sealed digestion method is used.

When using the COD rapid analyzer, some related matters need to be paid attention to, as follows:

1. The wall thickness of the new digestion tube is uneven and should be screened before use. Take a batch of digestion tubes, add 5 mL of 0.025mol/L potassium dichromate solution for digestion and measurement, and select the COD measurement value.≤3mg/L digestion tube. In addition, the digestion tube has directionality during colorimetric measurement, and cannot be placed in the wrong direction.

2. The sample digestion process needs to be carried out in a ventilated place, and the acidity of the solution is relatively high to prevent accidental burns during operation.

3. In the standard series of COD rapid analyzers, if a very small amount of precipitate (mercury sulfate) is precipitated at the bottom of the colorimetric tube after digestion and cooling, it will have no effect on the determination result.

4. If the color of the solution is uneven after all the reagents are added, it should be fully cooled and shaken, and then digested.

5. Before the colorimetric measurement of the COD rapid tester, the tester should be preheated for 30 minutes before it can be measured.

6. Glassware such as colorimetric tubes, pipettes, graduated cylinders, and beakers used in the entire measurement process must be cleaned before use, so as not to affect the measurement results.

7. For water samples with COD mass concentration<50mg/L, be sure to use low-concentration digestion solution to digest and take parallel double samples for measurement to reduce the measurement error.

8. For the types of wastewater not covered by this method, it is necessary to compare experiments with the standard method before deciding which digestion method is applicable.

9. The COD rapid tester faces the tester with the white label of the test tube for each test.

10. The blank sample has a great influence on the test results, and the blank sample should be measured in parallel. Main business: standard COD digester, COD online monitor, ammonia nitrogen analyzer, BOD5 analyzer, hydrogen content analyzer, infrared carbon and sulfur analyzer, microcoulometric titrator.