1. Kjeltec Instrument
Title slide with Total Nutrition

2. Instrument – Kjeltec
DIGESTION UNIT
DISTILLATION UNIT

3. Objective
To Share the Knowledge on Kjeltec Instrument in the following areas
Principle
Protocol
Solution Preparation and Standardization
Recovery Studies
Critical control points
Trouble shooting
Conclusion.

4. Principle
Digestion Distillation Sample + Catalyst + Ammonium Sulphate + Sulphuric acid Strong alkali 410ºC ▲ 45 mins pH- 8.4 Nitrogen Releases in the Ammonia Releases form of Ammonia 4% Boric acid Ammonium Ammonia + Sulphuric acid (Receiver Solution) Borate Ammonium Sulphate

5. Principle in reaction Distillation Step 1
Digestion
Acid & Catalyst
N(feed) (NH4)2SO4
Distillation
Step 1
(NH4)2SO4 + 2 NaOH NH3 + 2H2O + Na2SO4
Step 2
NH3 + H3BO3 (boric acid) NH4+ + H2BO3- (borate ion)
Titration
H2BO3- + H H3BO3
The concentration of hydrogen ions required to reach the end-point is equivalent to the concentration of nitrogen that was in the feed/raw material

6. Expected Protein % of the sample Weight taken for the analysis
Procedure
PROCEDURE FOR DIGESTION
Weigh the sample as per the table given below to nearest to mg in the digestion tube.
Catalyst – 7g of Potassium Sulphate and 0.8g of Copper Sulphate per sample.
Conc. H2SO4
Cool the content of the tube before distillation.
Based on the protein value we have to alter the sample quantity for the analysis. The quantity of sample is given below.
Expected Protein % of the sample
Weight taken for the analysis
<20 %
1000mg
>20 %
500mg

7. Procedure Instrument Keys
Menu 1) Analyze – Upon choosing this function complete
Analysis will take automatically
2) History - It will show all the history that
We did previously
3) Settings - It has the full system settings
4) Manual - By manually we can choose the specific
Automatic Addition of Alkali, Water , Distillation time, Steam Pressure can be programmed by editing the ranges

8. Solution Preparation Receiver Solution
Boric Acid: % Solution gm in 100ml of warm Water +
1.0 ml of BromoCresol Green
0.7 ml of Methyl red
Methyl Red: - 100mg in 100ml of methanol
BromoCresol Green :- 100mg in 100ml of methanol

9. Solution Standardization
0.1N Hcl: ml Conc. Hcl in 100ml of Distilled water.
(Titration Solution)
Standardization:-
Prepared 0.1N Hcl titrate against 0.1N Already Standardized NaOH
Phenolphthalein Indicator
(3 to 5 drops)
Appearance of the Pink Colour
Calculation:-
V1 X N1 = V2 X N2

10. Recovery Studies 0.1% Ammonium Sulphate solution:-
By Distillate the above mentioned solution directly – We can get the N% of the compound
N% of Ammonium Sulphate is – 21.09%
Calculation
Recovery % = Value obtained for Ammonium Sulphate
X 100
21.09
Note:-
Recovery Need to be done every day
After preparing fresh solution(Boric acid, Hcl, NaOH)

11. Critical control points in Digestion step
Weighing of the sample
Sample should not stick on to the sides of the tubes.
Adding enough quantity of acid
Digester – Connected to UPS / Stabilizer
After completion check the digestion is fully completed or not.(Green colour indicates completion digestion)
Should run with placing all the 8 tubes.
If digestion not done properly – Place the same to some more time for complete digestion
Vapor outlet need to be connect with water.
Fume hood should always turned on during digestion
Use respective PPE while using acids.

12. Critical control points in Distillation step
Once the tube cooled – use for distillation
Connect the instrument in UPS/ Stabilizer
Check the recovery
Check the NaOH and Distilled water quantity
Use glass pippete for taking the 30ml receiver solution.
Always use automatic mode for distillation
Manual method – Manually the distillation need to be stop down, Otherwise May leads to overflow of the collected solution
If the water cannot able to condense the instrument will show the warning message , Options – OK – The tube will get drained off
- Cancel - Instrument will wait until the normal condense happen
CONTD….

13. Critical control points in Distillation step
Tube drain need to be in off mode – To avoid the drain down before completing of distillation.
Water pipeline need to be connect and the tap on during the analysis for condensation
Fixing the tube should be proper – Otherwise the sample or ammonia will leak from the tube leads to wrong results
Collect 200 ml of the solution
End Point – Change from green color to colorless.

14. Calculation
N% = (T-B) X 14 X N.of Hcl X 100 Sample weight CP = N% X 6.25

15. Problem Faced and Trouble Shooting
1) Catalyst - Potassium Sulphate contains 2% Nitrogen content . 2) Digestion tube thickness 3) Power Fluctuation

16. Finding 1 Catalyst – Nitrogen Contribution
Catalyst used for Protein digestion always should be free from Nitrogen content.
Merck, Sigma contains less than 0.005% of nitrogen
FINAR brand - contains 2% of nitrogen content.
Problem Faced:-
Increased value in CP results in all the samples
Route cause Identification:-
Individual Digestion and distillation on every individual chemical involved in both digestion and distillation.
Found all the others are giving negative and Potassium Sulphate alone is the route cause for the problem.
Preventive actions:-
Branded Company like Merck / Sigma is advised to use for catalyst
Before Preparing catalyst, the Catalyst salt need to be measured on nitrogen content.

17. Findings 2 Impact by Digestion tubes – new findings
Digestion in the Kjeltec Digestion tube – placing for 45 mins at 415ºC
The old tubes are thin and wide and the newly ordered tubes were thick and narrow
Problem Faced:-
Decreased value in CP results in some samples.
Route cause Identification:-
Did the analysis with the same samples in all the slots – Avg of 5 % Difference was found out between the slots
Done the same sample of analysis with thin and narrow tube and Done the same sample of analysis with thick and narrow tubes.
Thin tubes all the results were matching with each others and thick tubes major difference were obtained between the samples.
Due to more thickness the heat is not able to digest the sample properly.
Preventive actions:-
Stopped using the Thick tubes and ordered new tubes with provided clear information to the supplier.

18. Finding 3 Power Fluctuations
Impact on Digestion Unit:-
The Digestion unit consist of
– Power house of the Digestion unit
contactor and the heating cable
Problem Faced:-
The Contactor and heating cable was frequently functioned down.
Route cause Identification:-
It found out by Service person that the output from the plug point is very high and it fluctuates caused the problem in the damage of the parts
Preventive actions:-
Always advices to Connect the Digestion unit in Stabilizer

19. Finding 3 Power Fluctuations
Impact on Distillation unit
Problem Faced:-
The fuse will be always getting down and some time the inner wire got burnes.
Route cause Identification:-
It found out by Service person that the output from the plug point is very high and it fluctuates caused the problem in the damage of the parts
Preventive actions:-
Always advised to Connect the Digestion unit in UPS

20. Conclusion
By Following all the Critical control measures the instrument and analysis will be always perfect and believable.