Procedure for Distilling Samples on the Kjeltec 2300 Analyzer Unit

Operation

  1. Turn power on.
  2. Turn printer on.
  3. Turn water on.
  4. Go to manual mode.
  5. Flick titrating tube to get bubbles out. Dispense titrant several times to get bubbles out.
  6. Go to steam on. Press arrow key to turn steam on. Allow to warm up for 5 minutes.
  7. Press arrow key to turn steam off.
  8. Go to analysis mode.
  9. Select program.
  10. Go to result. Select blank.
  11. Have tube containing water in place.
  12. Close door.
  13. Run at least two blanks. Make sure the blank value is around 0.10 or less.
  14. Go to result and change to % Nitrogen. (The blank number above should read the last blank value you ran.)
  15. Put a tube with 1 mL of the 1% N solution standard and some water in place. Input 1.0 for the weight.
  16. Close door and let run. Readout should be close to 1% (+ 0.05%).
  17. Proceed with samples. Run the glycine check first. Input the correct weight for each sample. (The result for the glycine check should be close to 18.66 % N.)
  18. If you have blanks within the set run a tube with just water first to flush out the system, then run the blank. (Change result to blank for running the blank then back to % N for the samples. Input the weight for the samples as above.)
  19. Record numbers from printout into nitrogen book and onto lab sheets with 2 decimals.

Calculations

  1. %N = 14.01 x N H2SO4 x (mL acid)/(sample wt(g) x 10)
  2. % Crude Protein = %N X 6.25

Shut Down and Maintenance

Daily

  • Place tube with water in unit. Select manual. Go to steam on. Press arrow key and allow generator to run for about 5 minutes. Press arrow key to turn steam off. Remove tube and dispose of contents.
  • Turn power off.
  • Turn water off.
  • Turn printer off.
  • Clean drip tray. Clean the shield. Rinse and inspect the rubber adapter. Wipe any spillage with a damp cloth. Squirt water into titration vessel and onto pins to clean.
  • Place empty tube in unit and close shield.

Weekly

  • Check and clean around reagent tank screw caps to remove crystals. Every one to three months:
  • Clean alkali pump. Put 2 L of warm distilled water in a beaker. Put alkali tube into beaker. Select manual mode. Select add alkali several times. Empty distillation tube as needed. (A rinse using a half a liter of warm water is sufficient.) Replace hose into alkali tank. Flush out residual water and remove entrapped air.
  • Clean receiver solution dispensing system as above only if contamination has occurred.
  • Check volume of alkali. Go to manual mode. Select the pump you want. Measure dispensed liquid. Adjust as necessary.
  • Check volume of receiver solution. Put drain tube into measuring cylinder. Go to manual mode. Select add receiver. Adjust as necessary.
  • Clean splash head. Put 25 mL distilled water and 25 mL acetic acid into distillation tube. Select manual. Go to steam on for 5 to 10 minutes. Turn off steam. Replace tube with tube containing 50 mL distilled water. Distill for 5 minutes. Repeat the distillation three times with fresh water.

Yearly

  • Inspect all tubing and connectors.

References

  1. Brenner, J. M. 1965. Total Nitrogen. In C. A. Black (ed) Methods of Soil Analysis, Part II, SSSA., Madison, Wis. p.1149-1178.
  2. Horwitz, W. (ed). 1970. Official Methods of Analysis of the AOAC, 11th Edition, Washington, D. C. p.16-17.
  3. Tecator Manual. Kjeltec System 2300 Distilling Unit. Tecator, Hoganas, Sweden.