The DUMATHERM® N-Pro Combustion Analyzer uses all of the advantages of the Dumas combustion method and enables labs to analyze a wide range of samples. DUMATHERM® reduces analysis time to 3 minutes or less and 98% time savings compared to Kjeldahl. Learn more about our fully-automated combustion analyzer, that can deliver results within 3 minutes!

1. DUMATHERM®
Nitrogen Determination Made Easy

2. 2
1. Nitrogen Determination According to Dumas / Kjeldahl
2. Sample Preparation
3. Liquid Sample?
4. Sample Handling (Autosampler)
5. Advantages of Dumatherm
6. Results
7. Methods and Reference
8. Consumables
9. Summary – Features & Benefits
Table of contents

3. 3
1. Nitrogen Determination
According to Dumas / Kjeldahl

4. 4
CnHmNx + H2SO4
400 °C
Oxidation with boiling sulphuric acid:
Johan Kjeldahl, 1883:
n CO2 + 1/2 m H2O + x (NH4)2SO4(solv)
Oxidation with pure oxygen:
Jean Dumas, 1833:
1030 °C
[catalyst]
CnHmNx + a O2 n CO2 + ½ m H2O + x N-Oxides
How can we determine the nitrogen?

5. 5
Kjeldahl
sample digestion
ammonium sulphate
(NH4)2SO4
NH4H2BO3
steam
distillation
ammonium
NH3
titration
ammonium chloride
NH4CI
• 60-80 samples can be
measured, in 8 hours
Required equipment:
• Digestion
(KJELDATHERM®)
• Distillation (VAPODEST®)
• Titrator
Optional:
• Turbosog / Vacusog

6. 6
• ~150 samples can be
measured, in 8 hours
Required equipment:
• DUMATHERM®
• Computer
Dumas
sample
sample
preparation
sample + tin
nitrogen (N2)
DUMATHERM®
(combustion)

7. 7
Presence time on the instrument for 20 samples
Weighing &
Startup
System
Weighing &
Startup
System
Analysis
5 min./ 1s
Digestion
2h/ 20s
Distillation Titra-
tion
Operator can do other work
presence time free time
60 min. 180 min. 280 min. 300 min.
60 min. 150 min.
Kjeldahl
Dumas

8. 8
Dumas method
Dumas, 1833: Oxidation with pure oxygen:
1030 °C
[catalyst]
CnHmNk + a O2 n CO2 + ½ m H2O + k NOx
NOx N2
800 °C
[catalyst]
combustion
(oxidation)
(reduction)
Jean-Baptiste Dumas
(1800-1884)

9. 9
Dumas method
carrier gas
(CO2)
sample+(CuO)
(CnHmNk)
copper oxide (CuO)
CO + 2CuO  CO2
CH4 + 4CuO  CO2 +2H2O
potassium hydroxide solution (KOH 50%)
KOH + CO2  K2CO3 + H2O
copper wire/mesh (Cu)
2NOx + Cu N2 + CuO
nitrogen (N2)
H2O, CO2,
CO, CH4,
NOX, N2,
H2O, CO2,
NOX, N2
H2O, N2,
CO2

10. 10
 No release of toxic gases and usage
of masses of chemicals e.g. sulphuric
acid or sodium hydroxide)
 No expensive fume cabinet necessary
Advantages of Dumas:
Work safety
Saves work space

11. 11
 No additional space requirement.
 No canister necessary
 Fast analysis of samples in just 3-5 minutes
Advantages of Dumas:
Small footprint
Good waste management
Saves time and money

12. 12
2. Sample Preparation

13. 13
 As a difference to Kjeldahl we have to wrap the sample
 This is typically done with tin foil
 Airtight packing
Sample preparation and weighing

14. 14
Preparing the sample:
Ash insert with combustion residues.
Shape of the encapsulated samples refers to the diameter of the ash insert
in order to fully use its capacity. Especially when working with big sample
sizes, the ash insert has not to be changed as often as with irregularly
shaped samples.
Encapsulating device for samples

15. 15
 New weighing tool allows easy handling of samples weights at from
10mg to 500mg without problem with only one foil. Working by hand you
need usually two foils
 More capacity in ash insert due to better stack ability
 Standardization of weighing process
contains air
(78% nitrogen in air)
Reduce costs with sample preparation
no contamination
with air

16. 17
3. Liquid Sample?

17. 18
Superabsorbent for liquid sample
Suitable for nearly all liquid sample types:
water, beer, juice, starch milk, wastewater, soya
sauce, milk, liquid fertilizer, oil, mayonnaise, ketchup,
…
H2O
Superabsorbent polymer
Hydrogel
(Superabsorbent + water)

18. 19
• Extremely economical with nearly ash free combustion. Up to 80% price
saving.
• Up to 50% Absorber saving compered with Dumasorb.
• Liquids like water, beer, juice, milk, soya, liquid fertilizer, oil, mayonnaise,
ketchup can be with weighing tool and measured.
Sample preparation for liquid sample

19. 20
4. Sample Handling
(Autosampler)

20. 21
Sample handling
• Weighing of samples in Transfer Plate
• Error free transfer of 64 samples
• Simultaneous transfer of all samples just by gravity without manual handling

21. 22
• Robust Construction due to gliding rails
• No bent tubing possible
• Better protection from hot combustion tube
• Easy to lift and connect – no possibility to drop the sampler
Sampler 64+ concept + handling

22. 23
• Effective and fast purge of sampler by Helium supply
• Low and stable blanks
• 64-Position standard sampler (100 and 144 also
available)
Flexible sampler configuration

23. 24
Sample Sample tablet
O-Rings, 3 x
How the autosampler works

24. 25
carrier gas
How the autosampler works

25. 26
 X-Y-movement of sample tray
Easy to load and easy to follow up
 add further samples easily possible
 Emergency samples at any time in „special samples
 easy handling of the samples through the transfer plate
Advantages of XY Autosampler (DUMATHERM® N
Pro)
No confusion of samples
Continuous work
Not resorting necessary
No transfer errors

26. 27
5. Advantages of DUMATHERM®

27. 28
Sample (CnHmNk)
CO2, H2O,
N2, NOx
N2N2, CO2N2, CO2, H2O
1
2
3
-H2O
1. Condensation trap
2. Membrane system
(Permapure™)
3. Absorption trap
-CO2
Self
regenerating
adsorption trap
TCD
Thermal
Conductivity
Detector
adsorption
AS
AI
CF
AS Autosampler
AI Ash insert
CF Combustion furnace
RF Reduction furnace
RF
carrier gas
O2
H2O
HeN2
Purge gas N2
outer tubingInner tubing
permeable to water
H2O
H2ON2 He
Purge gas N2
Nitrogen determination with DUMATHERM
®
Gas in
Gas out
U
U out
R I

28. 29
Troubleshooting Leak test
• Fast leak test within 2 min.
• One Test for whole system
• Easy diagnosis 6 positions for possible leaks
• The connections are easily accessible from the
front of the Dumatherm
FC1
FC2
0%
0%
50%
100% dry air/ N2
FC1
FC2
1
2
3
-H2O
1. Condensation trap
2. Membrane system
(Permapure™)
3. Absorption trap
-CO2
Self
regenerating
adsorption
trap
TCD
Thermal
Conductivity
Detector

29. 30
 Rapid start up (30 min.) (Heating, system test, leak test)
 Less calibration work due to the innovative design and
advanced TCD detector
 No reference gas stream for the Detector is necessary.
 Reliable results within 3-5 minutes
Advantages of DUMATHERM®
Quickly ready for use
Calibration stable over years
Use of helium is minimized
Fast Analysis

30. 31
Lower operating costs than any other Dumas solution:
 The unique three-stage water separation ensures a much
longer lifetime of the water separators.
 The software allows precise combustion - for low oxygen
consumption.(with an oxygen bottle more than 32000 samples)
 The tested quality catalysts are sufficient for more than 1000
tests (depending on the sample)
Advantages of DUMATHERM®
No problems with aqueous samples
Oxygen is not wasted
Saves money

31. 32
6. Results

32. 33
Sample Results with Argon
Type Target % N % N % SD
Flour 2722 (150 mg = 2,6 mg N) 1,75 1,76 0,01
Milk powder 2868 (150 mg = 6,2 mg N) 4,14 4,15 0,01
Rapeseed 4336 (150 mg = 6,5 mg N) 3,30 3,27 0,02
starch 3288 (150 mg = 0,04 mg N) 0,019 0,036 0,02
starch 3288 (300 mg = 0,08 mg N) 0,019 0,019 0,004
starch 3289 (150mg = 0,06 mg N) 0,034 0,037 0,005
starch 3289 (300 mg = 0,12 mg N) 0,034 0,037 0,002
for N Standard Deviation
RSD [%] 0,56
Time
Weight
[mg]
Sample name
149,860
09.12.2014 11:14:06
09.12.2014 11:05:13
Moisture
[%]
04-12-14_EDTA (L-L-Q ) EDTA
Flour 2722 149,808
Flour 2722 150,361 5,71 8,451E+02
0,06
Date
10:56:24 8,490E+02
Protein
[%]
Nitrogen
[%]
Calibration number
and standard name :
09.12.2014 5,71Flour 2722
N Weight
[mg]
0,010
0,557
10,05
Nitrogen
Peak Area
[mV*s]
Protein
factor
10,11
Average
1,7712,654
1,760
5,71 8,365E+02 2,615 1,746 9,97
09.12.2014 11:00:47 Flour 2722 150,263 5,71 8,490E+02 2,654 1,766 10,09
2,642 1,757 10,03
09.12.2014 11:09:42 Flour 2722 149,683 5,71 8,431E+02 2,636 1,761 10,06

33. 34
Participation in the ringtest (Helium)
VDLUFA, MUVA, GAFTA
Sample
Dumatherm Ø Kjeldahl Ø Δ Dumas-Kjeldahl
[%] N[%] N [%] SD [%] Protein [%] N [%] SD [%] Protein
VDLUFA
Feed 2,650 0,018 16,565 2,638 0,006 16,485 0,013
Feed 5,600 0,017 35,003 5,617 0,027 35,108 0,017
MUVA
yoghurt 0,770 0,002 4,916 0,770 0,003 4,914 0,000
UHT milk 0,540 0,003 3,443 0,531 0,002 3,385 0,009
GAFTA
Basmati Rice 1,380 0,008 8,62 1,350 0,004 8,43 0,030
soya meal 7,699 0,020 48,119 7,691 0,096 48,067 0,008

34. 35
Starch – Low Nitrogen Application
• Starch has only remaining traces of
nitrogen/protein
• Nitrogen/Protein determination is for quality
control of starch
• The lower the better
• Fast stability and good repeatability is a Must
• Stable blanks values mandatory
• Calibration strategy

35. 36
Results with Potato Starch
• Excellent repeatability close to true detection limit of 0.003 mg Nitrogen absolute
• No combustion additives needed for high carbon content samples
• Reference results in less than 4 minutes

36. 37
Topic: MEAT
• Salty/Fatty samples in DUMAS analysis
 Special handling?
 Possible Problems
 Solutions and easy workarounds
• Challenge for Sample preparation
• After homogenization samples can be weight in with 300-500mg

37. 38
Results FAPAS Canned Meat
11.05.2012 14:26:54 3336 220,140 16,10
1,543E+04 4,053 2,557 15,98
6,25
1,533E+04 4,026 2,558
2,153E+04 5,671 2,576
11.05.2012 14:22:16 3336 158,480 6,25
6,2511.05.2012 14:17:51 3336 157,394
3,873 2,553 15,9611.05.2012 14:04:34 3336 151,730 6,25
Nitrogen
[%]
Protein
[%]
16,01
0,06
0,40
2,561
0,010
0,403
15,99
Serial Number :
Software Version:
Time
159
DUMATHERM MANAGER V4.09
Weight
[mg]
Sample name
THAM lowN (L-L-L )Calibration mumber:
und standard name :
Standard Deviation
RSD [%]
Average
EDTA; THAM 1; THAM 2
Method :
Series Name :
B 1.4
FAPAS
Dumatherm Nitrogen / Protein Analyser
Operator :
N Weight
[mg]
Serviceman
Submitter :
Protein
factor
1,475E+04
Date
Nitrogen
Peak Area
[mV*s]
für N

38. 39
Milk
• Milk and Milk Products
 DIN/ EU norm for milk and milk products on Dumas
 Special requirements on milk on repeatability
• Liquid handling
• Requirement repeatability Protein (Kjeldahl): 3,591 ± 0,011 g/100g

39. 40
Excellent Milk Repeatability
Flow Rates:
o
C s
o
C s
o
C
3,775E+03 0,984 0,611 3,90
10.10.2013 10:45:43 Milch 3794 141,989 6,38 3,327E+03 0,866 0,610 3,89
10.10.2013 10:40:42 Milch 3794 160,960 6,38
Nitrogen
[%]
0,614
Protein
[%]
10.10.2013 10:35:31 Milch 3794 150,010 6,38 3,524E+03 0,918 0,612 3,90
3,90
0,01
0,29
0,612
3,92Milch 3794
Weight
[mg]
Sample name
Protein
factor
6,38
Serial Number :
Software Version:
Time
159
DUMATHERM MANAGER V4.11
for N Milchkalibration (L-L-L 0,002
0,286
Standard Deviation
RSD [%]
Average
sccm199,0
THAM; THAM 1; THAM 2
Times:
Sample Delay
sccm
Method :
Series Name :
C 1,6
Okt 13
Dumatherm Nitrogen / Protein Analyser
650Reduction Reactor
Combustion Reactor He I
Date
He II
141,893
980 9
Sample Stop 13
Operator :
N Weidht
[mg]
0,871
Nitrogen
Peak Area
[mV*s]
Degassing Oven
10.10.2013
Serviceman
Submitter :
Temperatures:
10:30:23
194,0 sccm
Calibration number
and standard name :
200,0 Run Time Auto298
3,347E+03
O2

40. 41
Repeatability Test with different weights

41. 42
7. Methods and Reference

42. 43
Official approvals of the Dumas Method
 AOAC 992.15
 AOAC 928.08
 § 64 LFGB 06.00-20
 AOAC 993.13
 DIN EN 13654-2
 DIN ISO 13878
 OIV-MA-AS323-02A
 AOAC 920.53
 AOAC 950.09
 AOAC 997.09
 MEBAK 2.6.1.2
Meat
Agriculture /
Fertilizer
Beer
Wine

43. 44
Official approvals of the Dumas Method
 DIN EN ISO 16634
 AOCS Ba 4e-93
 AOAC 992.15
 ISO 14891
 IDF 185
 § 64 LFGB 01.00.60
 § 64 LFGB 02.00.24
 § 64 LFGB 03.00.27
 AOAC 976.05
 AOAC 968.06
 AOAC 990.02
 AOAC 990.03
 AACC 46-30
 GAFTA Method 4:2
 European
Pharmacopoeia 5
method 7
Oilseeds
Milk and
Milkproducts
Pharmacy
Feed

44. 45
Official approvals of the Dumas Method
 DIN EN ISO 19051
 ISO 24698-1
 AOAC 992.23
 AACC 46-30
 GAFTA Method 4:2
 ICC Standard No. 167
 ISO 16634-1
 ISO TS 16634-2
 AOCS Ba 4f-00
 § 64 LFGB, methods
17.00-18; 18.00-18;
22.00.2; 48.01-26
 DIN EN 16168 (N)
 DIN EN 10694 (C)
Environment
Foods
Rubber
Grain

45. 47
8. Consumables

46. 48
Exchange of reactor tubes
 LR approx. 1000 Measurements
 RR approx. 500 Measurements
 Exchange of ash insert
Replacement depending on application.
Typical approx. 120 - 150 measurements
 Cleaning of reactor connection at the bottom
(recommended every 1000 combustions)
 Cleaning sample feeder
Standard operations by user
DUMATHERM® Principle

47. 49
Exchange of reactor tubes
 LR approx. 1000 Measurements
 RR approx. 500 Measurements
 Exchange of ash insert
Replacement depending on application.
Typical approx. 120 - 150 measurements
 Cleaning of reactor connection at the bottom
(recommended every 1000 combustions)
 Cleaning sample feeder
Standard operations by user

48. 50
Combustion: Fast, Clean and Catalytic
CnHmNx + a O2 n CO2 + ½ m H2O + x N-
Oxides
1030 °C
[Catalyst]
Oxidation:
 Heavy metal free catalyst (good for the
health)
 Catalyst for full conversion without excess
oxygen
 Side reaction pyrolysis is suppressed
 Catalyst reduces the activation energy up to
400 °C. saving oxygen!

49. 51
Reduction with highly efficient DUMACop®
• Copper reacts 1 : 1, i.e.
stoechiometric reaction to copper
oxide
• Oxidations of the copper to black
copper(IV)oxide
N-Oxide N2
800 °C
[copper]

50. 52
Principle Adsorption + Desorption
• Molecular sieves based on zeolithes with
pre-defined poursize
• Adsorption based on the molecule size
• Temperature controlled equilibrium process
• Complete desorption at 350 °C which gives
a 100 % regeneration
• No need for chemical absorption with
NaOH

51. 53
Separation of Carbon Dioxide
• Chemical absorption materials like Ca(OH)2
Disadvantage: a lot maintenance
• Usage of CO2 as carrier gas, i.e.
separation not needed
Disadvantage: Drastically reduced
precision
• Adsorption/Desorption with suitable
adsorbents based on zeolithes
Disadvantage: None

52. 54
Easy and Automated Water Drainage
 Expansion and drainage, fully automized
 Software controlled drainage times
 Maintenance free Permapure gas dryer
 Regeneratable Water Absorber, easy refill
 Non-hazardous materials, no quartz wool for
packing
WetDry

53. 55
Reduce Costs with liquid samples
 New chemical free way of weighing in liquid
samples
 Total non-hazardous materials (no mask
necessary during weighing, easy storage,
non-moisture sensitive, cheap, …)
 Superabsorber burns without residue to CO2

54. 56
Reduce Running Costs
 Predictable Costs with Consumables Packages
 One-Box-Design with all necessary items
 High Quality, long lifetime, certified consumables in Packages DUMASet ®

55. 57
9. Summary – Features & Benefits

56. 58
Summary – Features & Benefits:
F: Catalytic combustion
B: Complete oxidation of all combustion gas components
F: Total combustion gas is analysed
B: Maximum precision
F: Reduced number of wear parts because of easy construction
B: Lower maintenance and service costs

57. 59
Summary – Features & Benefits:
F: Autosampler with high capacity of up to 144 samples
B: High productivity
F: Unattended operation possible: DUMATHERM N – 12 hours
B: Saving working hours and costs
F: Innovative detector - no reference gas necessary
B: Highest precision available and save helium

58. 60
Learn more at
www.oico.com/dumatherm