Experimental equipment and consumables
COD prefabricated reagent (0-150mg/L), COD prefabricated reagent (100-15000mg/L), some distilled water,
1 100-1000μL pipette, 1 1-5ml pipette (other standard measuring tools can also be used), several matching pipette heads, 1 test tube rack
Reagent preparation
No preparation required, direct use
Detection method: (estimate the COD value of the water sample, and perform the detection according to the following steps)
Wear protective equipment as required during operation, and avoid contact with skin and clothing.
Don’t throw away the discarded reagents and the residual liquid after detection. They should be disposed of properly and safely.
If the indicated value of the instrument is not within the range of the test range, it cannot be regarded as the final test result. If you have any questions, please consult the after-sales service.
① When the estimated COD value of the water sample is 0-150mg/L:
A. Turn on the Detector and the digestion instrument to preheat (the digestion instrument can be set to 165°C, and the temperature will be raised in advance for 20 minutes)
B. Take several prefabricated reagent tubes (0-150mg/L) in the test tube rack
C. Blank sample: add 2ml of distilled water to the prefabricated reagent tube (0-150mg/L)
D. Sample to be tested: Add 2ml of the water sample to be tested into another prefabricated reagent tube (0-150mg/L) (if the water sample to be tested is not uniform, please shake it well before taking the sample)
E. Tighten the tube cap, pinch the tube cap and shake it upside down (the test tube is hot, be careful of burns)
F. Put the blank sample tube and the sample tube to be tested into the digestion instrument for digestion (165°C, 20min), please ensure that the tube cap is tightened before digestion
G. After the digestion is completed, shake the tube cap upside down by hand, and place the blank sample tube and the sample tube to be tested on the test tube rack to cool to room temperature
H. Select the test item of COD prefabricated reagent (0-150mg/L) on the Detector, according to the operation prompts, do blank calibration first, and then measure the sample to be tested (before testing, please ensure that the insoluble matter in the blank sample tube and the sample tube to be tested is completely Precipitation, clean outer wall, no scratches)
I. Data direct reading and printing
② When the estimated COD value of the water sample is 100-1500mg/L:
A. Turn on the Detector and the digestion instrument to preheat (the digestion instrument can be set to 165°C, and the temperature will be raised in advance for 20 minutes)
B. Take several prefabricated reagent tubes (100-15000mg/L) in the test tube rack
C. Blank sample: add 2ml of distilled water to the prefabricated reagent tube (100-15000mg/L)
D. Sample to be tested: Add 2ml of the water sample to be tested into another prefabricated reagent tube (100-15000mg/L) (if the water sample to be tested is not uniform, please shake it well before sampling)
E. Tighten the tube cap, pinch the tube cap and shake it upside down (the test tube is hot, be careful of burns)
F. Put the blank sample tube and the sample tube to be tested into the digestion instrument for digestion (165°C, 20min), please ensure that the tube cap is tightened before digestion
G. After the digestion is completed, shake the tube cap upside down by hand, and place the blank sample tube and the sample tube to be tested on the test tube rack to cool to room temperature
H. Select the test item of COD prefabricated reagent (100-1500mg/L) on the Detector, according to the operation prompts, do blank calibration first, and then measure the sample to be tested (before testing, please ensure that the insoluble matter in the blank sample tube and the sample tube to be tested is completely Precipitation, clean outer wall, no scratches)
I. Data direct reading and printing
③ When the estimated COD value of the water sample is 1000-15000mg/L:
A. Turn on the Detector and the digestion instrument to preheat (the digestion instrument can be set to 165°C, and the temperature will be raised in advance for 20 minutes)
B. Take several prefabricated reagent tubes (100-15000mg/L) in the test tube rack
C. Blank sample: add 2ml of distilled water to the prefabricated reagent tube (100-15000mg/L)
D. Sample to be tested: Dilute the water sample to be tested 10 times, and add 2ml of the diluted sample to another prefabricated reagent tube (100-15000mg/L) (if the water sample to be tested is not uniform, please shake it well before sampling)
E. Tighten the tube cap, pinch the tube cap and shake it upside down (the test tube is hot, be careful of burns)
F. Put the blank sample tube and the sample tube to be tested into the digestion instrument for digestion (165°C, 20min), please ensure that the tube cap is tightened before digestion
G. After the digestion is completed, shake the tube cap upside down by hand, and place the blank sample tube and the sample tube to be tested on the test tube rack to cool to room temperature
H. Select the COD prefabricated reagent (1000-15000mg/L) test item on the Detector, and perform blank calibration first according to the operation prompts, and then measure the sample to be tested (before testing, please ensure that the insoluble matter in the blank sample tube and the sample tube to be tested is completely Precipitation, clean outer wall, no scratches)
I. Data direct reading and printing (the indicated value of the instrument is the final concentration of the water sample)
④ When the estimated COD value of the water sample is greater than 15000mg/L:
It is necessary to dilute the COD value of the water sample to 100-1500mg/L, and perform the test according to the test method ②, the concentration of the water sample = the instrument indication value × the dilution factor.
