When your GC/MS is out of
Breath
Helium and the use of alternative GC
carrier gases
Lee Marotta, Mike Baylerian, Alan Gallaspy, Andy Tipler, Miles Snow
Outline
 Some background to Helium: where it comes from, who uses it, how
much it costs and why we should be concerned about consuming it.
 How to reduce wastage of Helium on a GC: method optimization and
elimination of leaks.
 Using alternative carrier gases. Benefits and trade-offs. Compatibility
with detectors, especially MS.
 Conclusion and questions.
Page 2
Background
Element
Abundance (%)
Hydrogen
73.90
SpaceHelium
(or to give it a more24.00
technical
Oxygen
name, 'The
Universe') is big.1.07
Really Big.
Carbon
Neon
0.46
0.13
Iron
Nitrogen
Silicon
Magnesium
Sulfur
Others
0.11
0.10
0.07
0.06
004
0.07
Douglas Adams, The Hitchhiker’s Guide to the Universe
Page 4
A1689-zD1
Helium is constantly being formed in
stars by thermonuclear fusion of
hydrogen at ~15,000,000K
Page 5
Gas
Abundance (%)
Nitrogen
78.08
Oxygen
The Earth:
20.95
0.93
Argon
Carbon Dioxide
0.04
Neon
0.0018
Mostly Harmless:
a small, blue-green
0.00052
world inHelium
one of the less fashionable
0.00017
sectorsMethane
of the galaxy.
Krypton
Hydrogen
0.00011
0.000055
Water
~1
Douglas Adams, The Hitchhiker’s Guide to the Universe
Page 6
NASA
Helium is able to Escape the Confines of Gravity
Helium
goes this
way
Page 7
Helium Formation on Earth
 Produced by the radioactive decay of isotopes of uranium and
thorium
 This is a very slow reaction
 Current natural reserves have been generated over the last 4.5
billion years!
 The earth’s crust contains 0.0008% helium
 Some natural gas contains up to 7% helium
Page 8
Helium Mining






USA (83%)
Algeria (11%)
Canada
Poland
Russia
Qatar
Amarillo, Texas
Page 9
Applications of Helium
Application
Lifting
15.1
Magnetic Resonance Imaging (MRI)
15.0
Welding
14.9
Chromatography
7.6
Heat Transfer
6.4
Leak Detection
5.6
Pressurizing
5.5
Fibre Optics
4.1
Diving Mixtures
4.0
Superconductors
2.9
Inert Atmospheres
2.7
Nuclear Magnetic Resonance (NMR)
1.3
Other
Page 10
Usage
(%)
14.9
The Price of Helium in the USA
United States Bulk Helium Cost vs. Year
14,000
12,000
Price per Metric Ton (U.S. $)
10,000
Price of Helium dramatically
8,000
Increasing every year
Price no longer
controlled by US
government
6,000
4,000
2,000
0
1930
1940
1950
1960
1970
Year
Source: U.S. Geological Survey
Page 11
1980
1990
2000
2010
One Man’s View - Helium will be Exhausted in 8 Years!
"The government had the good vision to store helium, and the question now is:
Will industry have the vision to capture it when extracting natural gas, and
consumers the wisdom to capture and recycle? This takes long-term vision
because present market forces are not sufficient to compel prudent practice.
When they stick that straw into the ground to suck out oil and gas, the helium
comes out, and if it doesn't get captured it drifts into the atmosphere and is lost.
Helium production is a side industry to oil and natural gas, an endeavor that
nobody wants to lose money on."
Lee Sobotka, Ph.D., professor of chemistry and physics in Arts & Sciences
at Washington University in St. Louis, December 2007
Government not funding the mining of Helium leaving it to industry
A lot of helium is not capture during drilling for oil, etc.
Page 12
Helium Balloons
Balloon retailers, which use about 7 percent of the (USA)
national supply, are already promoting conservation.
The International Balloon Association, a Wichita, Kan.based group of balloon manufacturers and distributors, is
asking its members to consider alternatives to helium, such
as good, old-fashioned air, particularly for balloons that don't
have to float. It's also promoting products that can extend
the float time of a balloon and decrease helium use by
about 25 percent.
Helium drifting away
St.Louis Post, January 2008
Page 13
Helium in Gas Chromatography
 Despite conflicting opinions and statistics, there is growing
concern about the availability and cost of helium
 Chromatography consumes 7.6% of the world’s helium supply
 As chromatographers, we can make a significant impact on the
total amount of helium consumed by:
• Eliminating wastage
• Using alternative gases such as hydrogen and nitrogen
 As instrument vendors we can design and provide tools and
techniques to assist users in this enterprise
Page 14
Saving Helium
Causes of Helium Waste
 Deliberate (e.g. from injector split settings in GC method)
 Non-Deliberate (e.g. from leaks)
Both of which can be easily addressed by the user
Page 16
What Lifetime is Expected from a Standard 8000L Cylinder?
Mode
Column
Flow Rate,
mL/min
Split flow
Rate,
mL/min
Septum
Purge Flow
Rate,
mL/min
Estimated
Cylinder Lifetime
with 1 GC, days
On-column
capillary (POC)
2
-
-
2771
On-Column
Capillary (PSS)
2
10*
3
369
Packed column
20
-
-
277
Packed Column
50
-
-
111
Splitless injection
2
25**
3
180
Split injection
2
25
3
185
Split injection
2
50
3
101
Split injection
2
100
3
53
Split injection
2
200
3
27
Split injection
2
500
3
11
* A small split flow is recommended to help keep the injector swept and clean
** The split vent is closed during injection so total usage is slightly reduced
Page 17
Cost of a Cylinder Containing 8000L 5N-Grade Helium
Page 18
Country
Example Cost (€)
USA
35
Taiwan
117
Germany
146
France
150
Italy
160
China
299
Brazil
507
The PerkinElmer Clarus Gas Chromatographs with PPC Pneumatics
Clarus 600
All these have support for
automated leak limitation
and detection
Clarus 500
Page 19
Conserve Helium by Turning Down the Split Flow Whenever Possible!
 Use a simple timed event
on the Clarus 500 or 600
GCs to reduce the split flow
rate after the injection is
complete
 For a lab of 5 GCs running
with 200mL/min split flows,
this single action, that
takes just a moment to
enter, will:
•
•
•
Page 20
Save up to €10,000/year in
helium costs
Eliminate up to 60 cylinder
exchanges/year
Contribute significantly to
helium conservation
Sources of Leaks
 Tank regulator
 Laboratory plumbing
 Connections to the GC
 Internal plumbing in the GC
 Injector septa and o-rings
 Column ferrules
 Column breakage
Page 21
Buy a Helium Sniffer – it will Save You Thousands of Euros!
Never use soap solution to locate leaks!
Page 22
Clarus GC PPC Split Pneumatics – Split Mode
Controller
Controller
Pressure
Sensor
Flow SensorProportional
Valve
Proportional
Valve
Injector
Column
Solenoid
Valve
• Leaks are detected by a sudden loss in pressure and the system is subsequently shutdown
after 2 minutes
• An automatic system leak-check may be performed at the start of each run – again the system
is shutdown after 2 minutes if a fault is detected
• In split mode, the PPC controller regulates the gas-flow into the injector so leakage will never
exceed this rate.
PPC Split Pneumatics – Splitless and Leak-Check Mode
Controller
Flow Sensor
Pressure
Sensor
Proportional
Valve
Injector
Monitored Output
Column
Page 24
Solenoid
Valve
Automatic Leak Checking with PPC
 Flow rate into injector
checked as a pre-run event
 If flow rate exceeds limit,
GC will shutdown
 Prevents major loss of
carrier gas
 Also reduces explosion risk
with hydrogen carrier gas
Page 25
Summary of Options to Reduce Helium Wastage
 Reduce or eliminate split flows when not needed
 Detect and eliminate leaks
Page 26
A Proposed Charter for Chromatographers
 Chromatographers
• Know how much helium you use (your Helium Footprint)
• Use instrument features to reduce splitting when it Is not
necessary
• Be mindful about detecting and eliminating leaks
• Consider using alternative carrier gases
 Vendors
• Provide tools for reducing and tracking helium usage
• Optimize injectors and detectors for use with other carrier gases
• Develop example applications and proof statements with other
carrier gases
• Encourage end users to reduce helium usage
Page 27
Using Alternative Carrier
Gases
Content
 Review of available gases
 Advantages and tradeoffs
 Compatibility with injectors, columns and detectors
 Mitigating the risks in using hydrogen
 Effect on performance
 Special considerations for MS
 Options for ATD and HS
Page 29
Review of Carrier Gases
Gas
Cost
Speed of
chromatography
Chromatographic
efficiency
Flow permeability
Supply
Safety concerns
Helium
Hydrogen
Nitrogen
Expensive
Medium
Low cost
Fast
Low cost
Slow
Low
Medium
High
Low
High
Low
Pressurized
tank
Pressurized tank or Pressurized tank
electrolytic hydrogen
or nitrogen
generator
generator
Highly explosive
Hydrogen cylinders
Pros
 Can keep up with substantial
demand if necessary
 Can usually get spare
cylinder quickly
Cons
 Safety concerns with
flammability especially with
large leaks or catastrophic
failures
 Inconvenient (and can be
dangerous) to move and
exchange
Hydrogen generator
Pros
 No heavy high pressure
cylinders to lug around
 Low internal volumes at low
pressure means small
hazard potential
 Intelligent shutdown in the
event of a fault
Cons
 High initial cost
 May not have spare
generator on hand for
backup
 Need to assess demand
accurately
Injector and Column Compatibility
 Injector Considerations
• Hydrogen – Very low viscosity requires low inlet pressure.
– Potential problems with short (30 m or less), wide bore columns (530
μm).
– MS further limits column dimensions
– Potential Problems with splitless and pressure pulse injections.
• Nitrogen - Optimal linear velocity requires low inlet pressure.
– Potential problems with short (30 m or less), wide bore columns (530
μm).
– MS further limits column dimensions
– Potential Problems with splitless and pressure pulse injections.
Injection Method Considerations with MS
Detector Compatibility
 Combustion Detectors (i.e. FID, FPD)
• Constant flow mode is preferable
• Baseline may change in constant pressure or velocity type
operation.
• Remember to combine carrier flow for total hydrogen for
combustion
 NPD
• Requires constant flow of hydrogen at ~1 mL/min
• Hydrogen is not a good choice for a carrier gas
 Single Quad MS
• Hydrogen potential reduces sensitivity by 2x
• High vacuum column outlet may constrain injector pressure
settings
MS System Performance
GC Sample Handling Devices
 Hydrogen is not an acceptable carrier gas for thermal
desorption type sample introduction.
 Hydrogen is not an acceptable carrier gas for pyrolysis sample
introduction, since a heated wire glows red hot in the injector.
 Hydrogen is an acceptable carrier gas for headspace sample
introduction when using appropriate safety measures
(including a special hydrogen needle).
Detailed Hydrocarbon Analysis using Helium and Hydrogen
Helium
160+ Minutes
Hydrogen
70 Minutes
More
Available
Time
Column Efficiency
Column efficiency
(hence peak shape
and resolution) is very
similar in this region
for all three gases
Clarus GC PPC Systems Support Velocity Control and Display
 Capillary column carrier
gas may be controlled by
setting the pressure, flow
or velocity.
 In each mode of control,
the current values of all
three are displayed in real
time
Method migration with carrier gas velocity control
30cm/s at 20°C/min
Helium
Same separation with the
same method with all
three gases!
Hydrogen
Nitrogen
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
10.5
11.0
11.5
12.0
Can I migrate methods with flow or pressure carrier gas control?
Constant Pressure at
10°C/min with Initial
Velocity of 30cm/s
Helium
Same separation if the
initial velocity is the
same!
Hydrogen
Nitrogen
7.0 7.5
8.0 8.5
9.0
9.5 10.0 10.5 11.0 11.5 12.0 12.5 13.0 13.5 14.0 14.5 15.0 15.5 16.0 16.5 17.0 17.5 18.0 18.5 19.0 19.5 20.0 20.5 21.0 21.5
Clarus GC PPC Split Pneumatics – Split Mode
Controller
Controller
Pressure
Sensor
Flow SensorProportional
Valve
Proportional
Valve
Injector
Column
Solenoid
Valve
• Leaks are detected by a sudden loss in pressure and the system is subsequently shutdown
after 2 minutes
• An automatic system leak-check may be performed at the start of each run – again the system
is shutdown after 2 minutes if a fault is detected
• In split mode, the PPC controller regulates the gas-flow into the injector so leakage will never
exceed this rate.
Automatic Leak Checking with PPC
 Flow rate into injector
checked as a pre-run event
 If flow rate exceeds limit,
GC will shutdown
 Prevents major loss of
carrier gas
 Also reduces explosion risk
with hydrogen carrier gas
Things the user can do to minimize risks in using hydrogen
 Ensure systems are leak free (and
re-check them periodically)
 Use an in-line snubber if you are
using high pressure cylinders
 Use a hydrogen generator rather
than a high pressure cylinder
 Route gas vents away from the
instrument
 Use PPC pneumatic systems to
limit and detect leakage and to
shutdown the system if necessary
 Install capillary columns so that
they don’t rub against other
surfaces
Special considerations for GC/MS
 Use caution when venting
• Shut down carrier gas before MS pumps
 Use extra caution after a power failure or unexpected failure of
vacuum system
•
•
•
•
Page 46
Shut down carrier flow
Do not turn MS system on immediately
Allow hydrogen to dissipate
Use a nitrogen purge accessory
GC/MS Drinking Water Tuning
Mass
51
68
69
70
127
197
525.1
10-80% of base peak
<2% of 69
n/a
<2% of 69
10-80% of base peak
<2% of 198
525.2
10-80% of base peak
<2% of 69
n/a
<2% of 69
10-80% of base peak
<2% of 198
525.3
n/a
<2% of 69
present
<2% of 69
n/a
<2% of 198
Helium
DFTPP
Helium
46.6
1.3
52.0
0.1
56.6
0.2
Hydrogen
DFTPP
Hydrogen
43.9
1.6
45.6
0.5
47.1
0.7
198
199
275
365
441
base peak or >50% of 442 base peak or >50% of 442
5-9% of 198
5-9% of 198
10-60% of base peak
10-60% of base peak
>1% of base peak
>1% of base peak
Present and < 443
Present and < 443
present
5-9% of 198
n/a
>1% of base peak
<150% of 443
100.0
5.4
23.2
1.9
79.5
100.0
6.3
24.3
2.5
78.8
442
443
base peak or >50% of 198 base peak or >50% of 198
15-24% of 442
15-24% of 442
present
15-24% of 442
64.7
19.7
75.3
17.7
Summary
 There is a compelling need to switch GC methods away from using helium
•
•
•
Cost
Sustained supply
Free up helium supplies for ‘more important’ purposes (e.g. MRI)
 There are feasible alternative carrier gases
•
•
Hydrogen
Nitrogen
 Chromatography equivalent to that obtained with helium carrier is possible
with hydrogen or nitrogen on GC systems that control and monitor gas velocity
through the GC column.
 Although there is risk of an explosion when using hydrogen, this will be very
small if the following are followed:
•
•
•
•
•
Hydrogen generator
Use PPC pneumatic controllers
Ensure that systems are leak-free
Route split vents etc. to the instrument exterior
Use a hydrogen sensor in the GC oven
Thank you!!!!!