Nitrogen cannot be used as carrier gas for GC. How sure are you about that? In this presentation we tackle what we call the “van Deemter indoctrination”. Take a look at our recent accomplishments and convince yourself to give it at try. Particularly now when more and more laboratories are suffering from inconsistent supplies of helium.

1. THE VAN DEEMTER
INDOCTRINATION
Nitrogen as Carrier Gas for GC?
Are you kidding!
www.is-x.be

2. This is a funny story…

3. This is a funny story…
about carrier gases in GC…

4. This is a funny story…
about carrier gases in GC…
and how we all got fooled.

5. Are you ready?

6. Keep staring in the center

7. Keep staring in the center

8. Keep staring in the center

9. You are suffering from
inconsistent helium supply

10. You have problems
implementing hydrogen

11. There is
NO ALTERNATIVE
!!!!!

12. We all know this story,
don’t we?

13. However…

14. Have you ever considered
nitrogen?

15. Probably not…

16. That’s because we all suffer from
the “van Deemter indoctrination”
Don’t worry, I’ve been a victim myself too…

17. Take a look at our experiences
and try to cure yourself too!

18. J. J. van Deemter was a briljant Dutch physicist.
He worked for the Royal Dutch Shell laboratory
In Amsterdam (The Netherlands) in the 1950s.
He was employed as chemical engineer and only
had little direct interest in chromatography.

19. In those days, the mathematical description of
the chromatography process was rather complex.

20. In those days, the mathematical description of
the chromatography process was rather complex.
This was mainly due to improper modelling.

21. However, after much experimentation and plotting,
a very simple equation could be derived.
van Deemter J. J., Zuiderweg F. J. & Klinkenberg A.
“Longitudinal diffusion and resistance to mass transfer as causes of nonideality in chromatography.”
Chem. Eng. Sci. 5:271-89, 1956.

22. This equation, which is known as the van Deemter
equation, was the first to describe the chromato-
graphic process correctly.

23. H = A + B/u + Cu
H = height of one theoretical plate, cm
u = average linear velocity, cm/s

24. H = A + B/u + Cu
In order to work under optimal conditions,
plate height H has to be minimal.

25. THE A TERM = EDDY DIFFUSION
Peak broadening due to path lenghts differences in packed
GC columns. A = 0 for capillary columns.

26. THE A TERM = EDDY DIFFUSION
Peak broadening due to path lenghts differences in packed
GC columns. A = 0 for capillary columns.

27. THE A TERM = EDDY DIFFUSION
Peak broadening due to path lenghts differences in packed
GC columns. A = 0 for capillary columns.

28. THE A TERM = EDDY DIFFUSION
Peak broadening due to path lenghts differences in packed
GC columns. A = 0 for capillary columns.

29. THE A TERM = EDDY DIFFUSION
Peak broadening due to path lenghts differences in packed
GC columns. A = 0 for capillary columns.

30. THE B TERM = LONGITUDINAL DIFFUSION
Peak broadening due to multidirectional diffusion.
Indirectly proportional to flowrate.

31. THE B TERM = LONGITUDINAL DIFFUSION
Peak broadening due to multidirectional diffusion.
Indirectly proportional to flowrate.

32. THE B TERM = LONGITUDINAL DIFFUSION
Peak broadening due to multidirectional diffusion.
Indirectly proportional to flowrate.

33. THE B TERM = LONGITUDINAL DIFFUSION
Peak broadening due to multidirectional diffusion.
Indirectly proportional to flowrate.

34. THE C TERM = RESISTANCE TO MASS TRANSFER
Peak broadening due to equilibrium kinetics in mobile and
stationary phase. Directly proportional to flowrate!
flowrate!
Stationary phase

35. THE C TERM = RESISTANCE TO MASS TRANSFER
Peak broadening due to equilibrium kinetics in mobile and
stationary phase. Directly proportional to flowrate!
flowrate!
Stationary phase

36. THE C TERM = RESISTANCE TO MASS TRANSFER
Peak broadening due to equilibrium kinetics in mobile and
stationary phase. Directly proportional to flowrate!
flowrate!
Stationary phase

37. THE C TERM = RESISTANCE TO MASS TRANSFER
Peak broadening due to equilibrium kinetics in mobile and
stationary phase. Directly proportional to flowrate!
flowrate!
Stationary phase

38. Both B and C terms react opposite to flowrate
changes.

39. Both B and C terms react opposite to flowrate
changes.
There is an optimal flow!

40. This is how a typical van Deemter curve looks like.
3,5
3
2,5
2
H, cm
1,5
1
0,5
0
0 0,5 1 1,5 2 2,5
Flow rate, mL/min

41. And this is the optimal flow region.
3,5
3 Optimal flow region
2,5
2
H, cm
1,5
1
0,5
0
0 0,5 1 1,5 2 2,5
Flow rate, mL/min

42. Key variables that determine curve shape and optimal
flow region are column ID and carrier gas type.

43. Key variables that determine curve shape and optimal
flow region are column ID and carrier gas type.

44. Key variables that determine curve shape and optimal
flow region are column ID and carrier gas type.

45. Influence of carrier gas type.
3,0
Nitrogen
2,5
2,0
H, cm
1,5
Helium
1,0 Hydrogen
0,5
0,0
0 0,5 1 1,5 2 2,5
Flow rate, mL/min

46. Experimental details.
3,0
Test compound: 2-ethyl hexanoic acid Nitrogen
2,5 Column: 20 m x 0.18 mm I.D. x 0.18 µm df
Phase: Rxi-5 Sil MS
Manufacturer: Restek (# 43602)
2,0
H, cm
1,5
Helium
1,0 Hydrogen
0,5
0,0
0 0,5 1 1,5 2 2,5
Flow rate, mL/min

47. Van Deemter tells us: “helium is acceptable”.

48. Van Deemter tells us: “helium is acceptable”.
We advise to use helium for all MS applications,
but do we really need it for GC/FID work ?

49. Van Deemter tells us: “hydrogen is best”.

50. Van Deemter tells us: “hydrogen is best”.
We advise to use hydrogen for fast(er) GC
applications. In combination with MS you have to
cope with a loss in sensitivity and a risk of activity.

51. Approach when keeping the same column:

52. Approach when keeping the same column:
Divide the isothermal stages of your oven program
by two and double all the programming rates (head
pressure stays the same).

53. Approach when keeping the same column:
Divide the isothermal stages of your oven program
by two and double all the programming rates (head
pressure stays the same).
Thus:
30C (2 min) to 250C at 10C/min (Helium)
=
30C (1 min) to 250C at 20C/min (Hydrogen)

54. Example 1: Solvent impurity analysis.

55. Example 1: Solvent impurity analysis.
TRACE GC-F ID A
Un kn own
Helium: 30 minutes
120000 120000
110000 110000
100000 100000
90000 90000
80000
70000
80000
70000
Column: 20 m x 0.18 mm I.D.
60000 60000
A
A
p
p
50000 50000
40000 40000
30000 30000
20000 20000
10000 10000
0 0
-10000 -10000
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34
Minutes

56. Example 1: Solvent impurity analysis.
TRACE GC-F ID A
Un kn own
Helium: 30 minutes
120000 120000
110000 110000
100000 100000
90000 90000
80000
70000
80000
70000
Column: 20 m x 0.18 mm I.D.
60000 60000
A
A
p
p
50000 50000
40000 40000
30000 30000
20000 20000
10000 10000
0 0
-10000 -10000
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34
Minutes
160000 TRACE GC-F ID A 160000
Hydrogen: 15 minutes
Un kn own
150000 150000
140000 140000
130000 130000
120000 120000
110000
100000
90000
110000
100000
90000
Column: 20 m x 0.18 mm I.D.
80000 80000
A
A
p
p
70000 70000
60000 60000
50000 50000
40000 40000
30000 30000
20000 20000
10000 10000
0 0
-10000 -10000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
Minutes

57. A little bit more in detail.

58. A little bit more in detail.
12 14 16
Minut es
Helium

59. A little bit more in detail.
12 14 16 6 7 8
Minut es
Helium Hydrogen

60. Example 2: Process analysis.

61. Example 2: Process analysis.
FID1 A, (1603JV04.D)
FID2 B, (1603JV04.D)
0.898
pA
7
6.5
6
5.5
5
4.5
4
3.5
0 2 4 6 8 10 12 min

62. Example 2: Process analysis.
FID1 A, (1603JV04.D)
FID2 B, (1603JV04.D)
0.898
pA
7
6.5
6
5.5
5
4.5
4
3.5
0 2 4 6 8 10 12 min
Helium: 44 minutes
Hydrogen: 14 minutes!
MXT column: 10 m x 0.53 mm I.D.

63. Example 3: Environmental analysis

64. Example 3: Environmental analysis
TRACE GC-FID-ar
SV MegaMix
42.5 42.5
40.0 40.0
37.5 37.5
35.0 35.0
32.5 32.5
30.0 30.0
27.5 27.5
pA
pA
25.0 25.0
22.5 22.5
20.0 20.0
17.5 17.5
15.0 15.0
12.5 12.5
10.0 10.0
7.5 7.5
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
Minutes

65. Example 3: Environmental analysis
TRACE GC-FID-ar
SV MegaMix
42.5 42.5
40.0 40.0
37.5 37.5
35.0 35.0
32.5 32.5
30.0 30.0
27.5 27.5
pA
pA
25.0 25.0
22.5 22.5
20.0 20.0
17.5 17.5
15.0 15.0
12.5 12.5
10.0
7.5
10.0
7.5
Helium: 25 minutes
0.0 0.5 1.0 1.5 2.0 2.5 3.0
Minutes
3.5 4.0 4.5 5.0 5.5 6.0
Column: 20 m x 0.18 mm I.D.
Hydrogen: 6 minutes!
Column: 10 m x 0.10 mm I.D.

66. But beware,

67. But beware,
It’s a struggle to convice company safety officers.

68. But beware,
It’s a struggle to convice company safety officers.
You need to invest in sensors.

69. But beware,
It’s a struggle to convice company safety officers.
You need to invest in sensors.
You need to invest in generators.

70. But beware,
It’s a struggle to convice company safety officers.
You need to invest in sensors.
You need to invest in generators.
And sometimes it simply does not work!

71. Example 1: Loss in capacity.
TRACE GC-FID-AR TRACE GC-FID-AR TRACE GC-FID-AR
28 cumeen cumeen cumeen 28
5-10-2009 13-35-40 CP5CB H2 cumeen.dat 24-09-2009 10-11-54 CC656 H2 cumeen.dat 29-09-2009 12-36-21 CC657 H2 cumeen.dat
Retention Time
Name
3,682
26 26
24 0.15 mm ID, 24
22
0.6 µm df (H2) 22
20 20
18 18
3,443
0.15 mm ID,
pA
pA
16 16
1.2 µm df (H2)
14 14
12 12
10 10
3,588
8 8
4,000
3,797
6 6
3,380
4
3,2 3,3 3,4
Reference:
3,5 3,6 3,7 3,8 3,9 4,0 4,1 4,2
4
Minutes
0.32 mm ID,
1.2 µm df (H2)

72. Example 2: Impurities in styrene.
Styrene Ethylbenzene

73. Example 2: Impurities in styrene.
Styrene Ethylbenzene

74. Results overview.
Ethylbenzene (He) Ethylbenzene (H2) Indane (He) Indane (H2)
1000
900
800
700
Conc, ppm
600
500
400
300
200
100
0
250 230 210 190 170 150
Injection temp, C

75. Results overview.
Ethylbenzene (He) Ethylbenzene (H2) Indane (He) Indane (H2)
1000
900
800
700
Conc, ppm
Internal standard 600
500
400
300
200
100
0
250 230 210 190 170 150
Injection temp, C

76. Results overview.
Ethylbenzene (He) Ethylbenzene (H2) Indane (He) Indane (H2)
1000
900
800
700
Conc, ppm
600
500
Ethylbenzene 400
300
200
100
0
250 230 210 190 170 150
Injection temp, C

77. And finally…

78. Last but not least…

79. Nitrogen…

80. Van Deemter tells us: “nitrogen cannot be used”.

81. Van Deemter tells us: “nitrogen cannot be used”.
Is this where it ends?

82. Van Deemter tells us: “nitrogen cannot be used”.
Is this where it ends?

83. We have implemented several nitrogen methods
successfully the last year.

84. We have implemented several nitrogen methods
successfully the last year.
We primarely aim at GC/FID methods.

85. We have implemented several nitrogen methods
successfully the last year.
We primarely aim at GC/FID methods.

86. We have implemented several nitrogen methods
successfully the last year.
We primarely aim at GC/FID methods.
7/10
instruments!

87. Approach when keeping the same column:

88. Approach when keeping the same column:
Just leave everything as it is
(including head pressure)!

89. Approach when keeping the same column:
Just leave everything as it is
(including head pressure)!
Thus:
30C (2 min) to 250C at 10C/min (Helium)
=
30C (2 min) to 250C at 10C/min (Nitrogen)

90. Example 1: Test mix.

91. Example 1: Test mix.
Carrier N2 1.5 mL #3 XIL-350_Mix He Front_FID2
15.00
Helium
pA
14.00
11 - 4.063
12 - 4.147 14 - 4.785
16 - 4.873
13.00 13 - 4.505
15 - 4.827 Column: 20 m x 0.18 mm I.D.
12.00
10 - 3.263
11.00
8 - 9 - 2.867
2.815
10.00
min
9.00
2.00 2.20 2.40 2.60 2.80 3.00 3.20 3.40 3.60 3.80 4.00 4.20 4.40 4.60 4.80 5.00

92. Example 1: Test mix.
Carrier N2 1.5 mL #3 XIL-350_Mix He Front_FID2
15.00
Helium
pA
14.00
11 - 4.063
12 - 4.147 14 - 4.785
16 - 4.873
13.00 13 - 4.505
15 - 4.827 Column: 20 m x 0.18 mm I.D.
12.00
10 - 3.263
11.00
8 - 9 - 2.867
2.815
10.00
min
9.00
2.00 2.20 2.40 2.60 2.80 3.00 3.20 3.40 3.60 3.80 4.00 4.20 4.40 4.60 4.80 5.00
Carrier N2 1.5 mL #3 XIL-350_Mix He Front_FID2
15.00
Nitrogen
pA
14.00
11 - 4.063
12 - 4.147 14 - 4.785
16 - 4.873
13.00 13 - 4.505
15 - 4.827 Column: 20 m x 0.18 mm I.D.
12.00
10 - 3.263
11.00
8 - 9 - 2.867
2.815
10.00
min
9.00
2.00 2.20 2.40 2.60 2.80 3.00 3.20 3.40 3.60 3.80 4.00 4.20 4.40 4.60 4.80 5.00

93. Example 2: Butyl acrylate.

94. Example 2: Butyl acrylate.
Helium
Column: 60 m x 0.32 mm I.D.

95. Example 2: Butyl acrylate.
Helium
Column: 60 m x 0.32 mm I.D.
Nitrogen
Column: 60 m x 0.32 mm I.D.

96. A little bit more in detail.

97. A little bit more in detail.
Helium

98. A little bit more in detail.
Helium Nitrogen

99. A little bit more in detail.
Helium Nitrogen

100. Example 3: Narrow bore column

101. Example 3: Narrow bore column
Nitrogen
Column: 10 m x 0.1 mm I.D.
2.00 min

102. Why does it work?

103. Why does it work?
Van Deemter is measured under isothermal conditions

104. Why does it work?
Van Deemter is measured under isothermal conditions
Van Deemter is valid for optimal conditions

105. Why does it work?
Van Deemter is measured under isothermal conditions
Van Deemter is valid for optimal conditions

106. Why does it work?
Van Deemter is measured under isothermal conditions
Van Deemter is valid for optimal conditions
Injection
Septum
Liner
Column

107. Why does it work?
Van Deemter is measured under isothermal conditions
Van Deemter is valid for optimal conditions
Injection
Septum
Liner
Column

108. Other methods:
Acrylates
Di- and triamines
BTEX
Non-aromatics
Primary aryl alcohols
Ethylacetate
Ethanolamines
Alcohols
Acetic acid
Light hydrocarbons

109. Don’t be afraid to challenge
van Deemter!

110. More information?
Dr. Joeri Vercammen
IS-
Managing Expert IS-X
www.is-x.be
j.vercammen@is-x.be
http://www.linkedin.com/in/joerivercammen
Also check out our other presentations!

111. Acknowledgements:
C. De Weerdt
E. Van Brussel
A. De Caluwé
R. Heus
P. Ryckaert
M. Van Lancker