Gas chromatography (GC) practitioners have traditionally used helium as their carrier gas, but a helium shortage is impacting labs around the world. Labs can no longer expect to get helium as inexpensively or reliably as they once could. As a result, GC and gas chromatography/mass spectrometry (GCMS) applications require an alternative.
Analytical laboratory scientists are increasingly turning to hydrogen, a cost-effective carrier gas that produces equal or superior GC and GC-MS results.
“The cost of helium will inevitably soar as resources diminish,” says Steve Westcott, chairman of Melbourn Scientific. “To avoid the issues around uncertain supply and the significantly increased costs of helium, it is recommended that the move to hydrogen for GC methods take place as soon as possible.”
A dwindling resource
Helium is mined by the petrochemical industry. During oil and gas drilling, prospectors will often find helium gas, which is produced on Earth when radioactive elements decay deep underground. In the early 20th century, the U.S. government sealed up helium caverns in Texas, creating the National Helium Reserve (NHR). The NHR was initially created as a source of helium to fill airships, but by the 1950s, it became apparent that helium would be much more useful for scientific and engineering practices.
In 1996, facing debts incurred by running the NHR, the U.S. ended federal control of the reserve. Helium’s cost dropped to around $40/1000 scf, and availability increased. Demand for helium continued to grow, with scientific and engineering industries using the gas for everything from MRI machines to superconductors. Worldwide consumption rose 3.6 percent per year between 1990 and 2008, from 3.28 billion scf to 6.3 billion scf, according to the National Research Council.
But as demand soars, supply plummets. The Bureau of Land Management—which controls the NHR—estimates that 16.2 billion scf, or around 60 percent of the U.S. national reserves, have now been sold.
Shortages and price volatility
On top of the helium reserve restrictions, modern helium mining is suffering. Natural gas found in shale rock is fast becoming the top fossil fuel source in the U.S., but helium cannot be collected from mining porous shale rock. The more the petrochemical industry collects shale gas, the less it will find and mine helium. Between 2008 and 2012, U.S. helium production fell by more than 6 percent, according to the U.S. Geological Survey.
Increasing demand, dwindling supply, and reduced mining caused helium prices to rise to $170/1000 scf in January 2013, the highest rate since privatizing the reserves. A global helium shortage is in full swing, with gas importers predicting that helium gas prices could now rise by 20 percent per year, every year.
This year the Responsible Helium Administration and Stewardship Act, a bipartisan effort, is making its way through the U.S. House and Senate. The legislation would restrict distributing helium from the national reserve, which makes up about 30 percent of the world’s helium.
Crucial medical and scientific applications that require helium, such as MRI machines, could continue to dip into the NHR under the proposed legislation. But for most labs, a steady helium supply is floating away from their reach.
Price volatility will challenge labs, but reliability of supply may be even more problematic. In testimony to the U.S. House in February 2013, Dr. Samuel Aronson, former director of the Brookhaven National Laboratory and vice president of the American Physical Society, highlighted some of the problems labs face due to erratic helium deliveries.
“Small researchers reliant on federal research grants continue to be subject to severe supply constraints and price shocks, which their research grants cannot accommodate,” noted Dr. Aronson. “They are being forced to either shut down experiments, invest in expensive recycle equipment using their own resources, or continue their work…in less-than-optimal conditions.”
Big laboratories also feel the helium pinch. According to Dr. Aronson, Argonne National Laboratories now receives only 70 percent of its allocation from its supplier, while Oak Ridge National Lab receives only 60 percent. And Sandia National Lab often receives delayed or short orders. “As a result, the laboratories have had to reprioritize some of their projects,” he said.
Hydrogen: the inexpensive choice
GC and GC-MS practitioners are looking for a more reliable solution than helium gas, and they are turning to options such as hydrogen—an abundant, less expensive carrier gas alternative.
In March, Bruker launched a GC system built specifically for hydrogen. “As we saw the supply problem intensifying and cost for helium rising, we knew we needed to step in,” said Meredith Conoley, marketing director for Bruker CAM.
“Our customers are looking at hydrogen carrier as they see benefits from reduced analysis time and now lower operating costs,” noted Conoley. “In some regions customers are reporting helium prices increasing as much as 200 percent while supply reliability decreases substantially.”
Meeting a need for speed
It’s not just about the price or supply. GC and GC-MS practitioners are also discovering that hydrogen yields the fastest results.
The research and development laboratory at International Flavors and Fragrances (IFF) changed its carrier gas from helium to hydrogen in early 2008. “For us it wasn’t all about finances,” said Steve Toth, a research investigator at IFF. “The main reason we made the change was because hydrogen allows us to speed up analysis, as is defined by the van Deemter curve. By replacing our helium carrier gas with hydrogen, we could decrease the analysis time and achieve the same resolution as with helium.”
The van Deemter equation predicts an optimum velocity at which there will be the minimum variance per unit column length and, therefore, a maximum efficiency. This proves that the linear flow rate of hydrogen can be greater than that of helium while offering equal efficiency in the gas’s ability to separate peaks.
This enables GC practitioners to perform more runs in shorter periods of time. “With hydrogen, our columns last longer, and our production times have dramatically improved,” said Bruce Williams, a senior technical advisor at Intertek. “The traditional GC run is 140 to 160 minutes. But by switching to hydrogen and using high-efficiency columns, you can get run times down to 40 minutes. We’ve reduced the time of our GC runs by 25 percent, and that helps production.”
Better resolution, superior results
Practitioners also credit hydrogen for improving GC and GC-MS results. “Hydrogen is well-suited as a replacement for costly helium in a lot of GC and GC/ MS applications as it often offers better chromatographic separation,” said Yassin Hardi, a GC and GC-MS sales engineer with CHROMTECH.
The van Deemter curve shows that using hydrogen provides a longer height equivalent to a theoretical plate (HETP), which leads to a greater number of plates for a column and can provide better resolution than helium. “Because hydrogen has a lower HETP value than any of the other GC carrier gas choices, its use results in the greatest column efficiency, observed as sharper peaks and greater resolution,” said Peter Quinto Tranchida of the Dipartimento Farmaco-chimico at the Università di Messina, Italy.
Easing the changeover
Practitioners looking to switch to hydrogen can turn to numerous guides and software packages to help ease and expedite the changeover.
Steve Toth changed 30 systems in the IFF lab, a switch that took approximately three to four months. While the changeover wasn’t too difficult, properly setting each system took time. “We had to go from GC system to GC system and translate each method from helium to hydrogen. Working in an applications-driven lab means you have a lot of different methods in operation, and we had to change each one, which took some time,” he said.
The benefits of hydrogen gas are clear, but the potential problems of storing cylinders of hydrogen gas can’t be ignored. A single, standard hydrogen cylinder storing 6,300 liters of gas has the explosive potential of 35 lbs. of TNT. Hydrogen is a colorless, odorless gas that can ignite in the presence of a static charge. A laboratory space needs a hydrogen/air mix of only 4 percent for the area to be explosive.
As such, labs that store cylinders of hydrogen gas need to manage storing potentially explosive cylinders and complying with safety regulations that are expensive to implement. Everything from temperature control to ventilation and even protection against seismic activity must be taken into account.
“Safety is of global importance to an institution,” said one safety expert at a leading U.S. academic research institution. He worked on campus in an older building that would have had to undergo a redesign to meet codes to safely store numerous cylinders of hydrogen gas. He noted safety codes were costly to meet, and the risk of injury associated with heavy cylinders would always linger. So he turned to an on-site gas generator for his hydrogen supply.
Unlike helium, hydrogen can be derived in a lab, via electrolysis. Modern generators using solid electrolyte technology, such as proton exchange membrane (PEM), can produce anywhere from 600cc to 60 liters of gas per minute at high pressure. Because a hydrogen generator contains little or no hydrogen at any one time, it is incapable of creating the 4 percent hydrogen/air mix necessary for a space to become explosive.
“Safety concerns led us to install four compact hydrogen generators, and the tangible benefits immediately became clear,” said the safety expert quoted above. “We were able to reduce the flammable gas volume in our building by more than 90 percent. It also freed up precious floor space and reduced physical injury risks associated with moving and connecting heavy cylinders, as well as reduced the time lost handling cylinders and changing regulators.”
He added, “Our campus safety personnel and fire marshal are much happier without hydrogen cylinders on-site.”
On-site hydrogen makes business sense
The long-term financial benefits of switching to hydrogen are clear. According to Siemens’ projections, a lab that converts to hydrogen will, on average, reduce carrier gas costs by 50 percent and make a return on investment within 20 months. For example, a lab running 30 systems will save more than $16,000 each year and make a return on its investment in less than 16 months.
Helium is a finite resource, so the current shortage problems are unlikely to abate in the long run. Hydrogen, on the other hand, is a reliable alternative that offers faster results—and will continue to become the carrier gas of choice for the GC and GC-MS industry.