Portable COD DetectorCOD is determined by sufficient strong oxidizing agents reacting with all possible substances in the sample. By measuring the difference in the consumption of the strong oxidizing agent, a specific formula is applied to calculate the sample's COD parameter. COD represents the amount of oxidizing agent consumed when treating water samples with a certain strong oxidizing agent under specific conditions. It reflects the degree of water pollution by substances. The higher the COD, the more severe the organic pollution in the water. COD is expressed in mg/L. Based on the COD values detected by water quality monitoring instruments, water quality can be categorized into five types. Type 1 and Type 2 waters have COD ≤ 15 mg/L, which generally meet drinking water standards. Water with a COD value exceeding Type 2 is not suitable for drinking. Type 3 waters have COD ≤ 20 mg/L, Type 4 waters have COD ≤ 30 mg/L, and Type 5 waters have COD ≤ 40 mg/L, all of which are considered polluted. The higher the COD value, the more severe the pollution.
Key Points for Using the Portable COD Detector
Please check if there is any splashing during the digestion of the water sample in the tube.
(1) Has the prepared reagent been left in the air for an extended period?
(2) After adding the reagent to the water sample, whether it is thoroughly mixed.
(3) Is the concentrated sulfuric acid analytical pure or has the sulfuric acid expired?
(4) Is the Dissolver temperature too high?
Prior to the experiment, the main unit should be preheated for approximately 15-20 minutes.
3.COD test tubes used for experiments should not be washed with detergent. Generally, they should be rinsed first with tap water and then with distilled water, dried, and kept ready for use to prevent detergent from adhering to the inner wall and affecting the measurement results.
When pulling the rod of the tensiometer, ensure that the measured cuvette is precisely aligned with the light path.
After pouring the reaction liquid into the cuvette, there are small bubbles rising to the surface, affecting the fluctuation of the digital display. Read the value after the numbers stabilize.
6. When conducting consecutive measurements of multiple samples, pour the solution from one corner of the measured cuvette, rinse it with distilled water, and carefully shake it dry before pouring in the new solution to be tested. The error introduced by this method is within the acceptable range. To minimize the error, during the measurement, the COD value of the water sample can be tested from low to high.
When pouring solutions from the cuvette, avoid spilling onto the transparent viewing window of the cuvette. Before the spectrophotometric measurement, check if the viewing window is clean. In addition to visual inspection, you can check the absorbance (A) of each cuvette to ensure the relative values are consistent.
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