Edible Mushroom Extract,Hericium Erinaceus Extract,Boletus Extract Fufeng Sinuote Biotechnology Co.,Ltd. , https://www.sntbiology.com
1. Turn on the DRB200 digester and preheat to 165 °C. See Instrument Program Updates for temperature and program settings and selections.
2. Unscrew the cover of the two COD fast digestion pre-formed reagents. Confirm that the reagents in the appropriate range are used.
3. Sample preparation: Hold a pre-formed tube reagent at 45° and pipette 2.00 mL of water sample into the pre-made tube with a pipette or pipette.
4. Blank preparation: Hold another preformed reagent and keep it at 45°. Pipette 2.00 mL of deionized water into the preform with a pipette or pipette.
5. Tighten the tube cap. Rinse the outer wall with water and dry with a clean paper towel. If the tube cap is not tightened, it may leak during the digestion process and cause inaccurate results.
6. Hold the portion of the tube cap and gently pour the pre-formed tube over the sink several times to mix the liquid, then shake the solid in the pre-formed tube to a suspended state. Prefabricated tubes become very hot during mixing.
7. Place the prefabricated tube into the preheated DRB200 digester and cover with a protective cover.
8. Wait approximately 8 minutes for the temperature of the digestor to rise back to 165 ° C. Wait for about 8 minutes to fill 15 prefabricated tubes, and less time for less prefabricated tubes
9. Start timing and heat for 20 minutes.
10. Turn off the digestor. Wait for the temperature to drop below 120 ° C and remove the prefabricated tube. (about 20 minutes) Note: The test tube cap is hot! Please be careful. Do not touch the glass part.
1. Select the test program. For details, see the user manual.
COD-- fast digestion method cod fast digestion working principle:
1. According to the COD fast digestion spectrophotometry, using COD standard concentration solution, draw a standard curve between absorbance and COD value.
2. Learn the principle of COD rapid digestion spectrophotometry and master its measurement method. In a sample of known concentration of COD standard solution, a known amount of potassium dichromate solution is added, and in a strong sulfuric acid medium, silver sulfate is used as a catalyst, and after high temperature digestion, the COD value can be determined by spectrophotometry.
(1) 1 mol of potassium hydrogen phthalate can be completely oxidized by 30 mol of potassium dichromate, and its chemical oxygen demand is equivalent to 30 mol of oxygen (1/2 O). Therefore, a known concentration of the COD standard solution can be configured using potassium hydrogen phthalate.
(2) Potassium dichromate can oxidize potassium hydrogen phthalate. When the COD value in the sample is 100~1000mg/L, the trivalent chromium (Cr3) produced by the reduction can measure the absorbance at 600nm±20nm. Then, the COD value in the sample is proportional to the increase in the absorbance of trivalent chromium (Cr3).
3. When the COD value in the sample is 15~250mg/L, the hexavalent chromium (Cr6) and the reduced trivalent chromium (Cr3) which are not reduced by potassium dichromate can measure the total absorbance at 440nm±20nm wavelength. The COD value in the sample is proportional to the decrease in total absorbance.
Fast digestion process:
11. Turn the top and bottom up several times while the prefabricated tube is still warm.
12. Place the prefabricated tube on the test tube rack and allow to cool to room temperature.
When the preformed tube is completely cooled, a colorimetric assay is performed.
2. Wipe the outer wall of the prefabricated tube with a damp cloth and wipe it off with a dry cloth.
3. Insert a blank into the circular sample cell.
4. Zero the instrument.
5. Press the READ key to read the result