Technology Forum: Gas Chromatography

From environmental monitoring and petrochemical research to food safety testing, gas chromatography has held its own as a prominent analytical technique.

Janet Kelsey, Electronic Editor, LCGC Europe approached a couple of experts in GC and asked them for their thoughts on the current status of the technique and how they perceive its future. Joining us for this forum are Margit Geissler, product manager of GC/GC–MS from Shimadzu and Bob Wiedemer, technical service chemist from Thermo Fisher Scientific.

What are the current trends in gas chromatography?

Geissler: Analytical methods are continuously improved to ensure optimal consumer safety as well as environmental protection and continuous increase in product quality. In particular, we see speed, automation and higher separation efficiency as trends in GC. Two-dimensional GC, including Comprehensive GC is, indeed, an important topic. There is also a trend towards reduction of the ecological footprint e.g., reduction of power consumption and carrier gas.

Wiedemer: The major current trend within gas chromatography is the move towards increased throughput, using faster methods of analysis. In terms of consumables, one way of achieving this is through the use of Ultrafast GC capillary columns, which deliver high speed analysis by combining short, narrow bore columns with extremely high temperature ramp rates. Direct column heating permits temperature ramp rates as high as 1200 °C per minute. Many analysts use unnecessarily long GC columns, which is inefficient in terms of both cost and analysis time. Correct sizing not only optimizes resulting data, but also increases the lifespan of the column.

What are some areas or applications in which gas chromatography will become increasingly important?

Geissler:Analysis of biofuels is a growing field for GC analysis as well as human healthcare, and consumer safety and security.Due to the recent acetonitrile crisis a lot of labs have considered changing their routine analysis from LC to GC. Compared with LC, gas chromatography usually provides better separation efficiency, on the condition that the compounds show enough volatility or can be derivatized to achieve higher volatility. Additionally, more methods for fast GC are being developed.

Wiedemer:In light of recent contamination issues with imported products, GC will be increasingly employed as a technique for the testing of imported food and consumer goods for safety reasons. With pesticides being commonly used to deter insects from various crops, it is important that high concentrations of these are not ingested, since they can prove harmful. As such, new applications within pesticide analysis are also being developed, and GC consumables and instruments are increasingly being used to accurately assess safety for consumption. Since food samples cannot be injected directly onto a column, there is a greater requirement for sample preparation techniques and equipment.The recent oil spill in the Gulf of Mexico has also kick-started researchers to apply GC techniques to applications within environmental testing. One such application involves the identification of polynuclear aromatic hydrocarbons in fish.

Are there any improvements that you would like to see in the gas chromatography industry over the next few years?

Geissler:In general, we expect the further improvement of multidimensional GC methods and new software concepts. In particular, more automation, ease of operation, precision, sensitivity and even easier software handling are required.

Wiedemer:One issue that has been highlighted by our sales team is the lack of standardization across vendor products. Standardizing consumables and accessories globally would not only benefit the industry in terms of growth, but also provide the customer with an additional level of flexibility to mix and match across manufacturers, as they choose. The design of instrumentation to use the same size/type of autosampler vials, injector liners and syringes, for example, would make processes much easier for each customer, especially since multiple researchers may use the same instruments.

Have you seen any major breakthroughs in GC technology at shows such as Pittcon and analytica this year?

Geissler:In the big picture, we did not see sensational breakthroughs in the sense of technological world premieres. But we have seen interesting innovations and novelties. From our point of view as a technological leader in GC, Shimadzu launched the new GC-2010 Plus providing excellent reproducibility and being equipped for fast GC. Last week we introduced the new quadrupole series GCMS-QP2010 Ultra and SE, by far the fastest and most sensitive systems in their classes.

What does the future hold for gas chromatography?

Geissler:The future is to deliver fast instruments and column technology, higher grade of automation and easier-to-use software, and high quality results through sensitive detectors, multidimensional and comprehensive GC as well as coupling techniques.

Wiedemer:As the requirements for increasingly sensitive experimental procedures increases, the manufacturers of instrumentation for gas chromatography have responded by increasing the sensitivity and selectivity of mass spectrometers. In order to facilitate this, lower bleed GC columns are being developed. Column-to-column reproducibility is equally important for consistent, reliable data from run-to-run. Furthermore, new columns are being manufactured which are extremely chemically inert, ensuring that the best peak shapes are obtained, even for highly active or difficult compounds that often cause peak tailing.Looking further into the future, we feel that sample introduction techniques will be re-addressed. Split/splitless injection is still the most commonly used technique and it has changed very little in the past 25 years. The more recent development of programmed temperature vaporizing (PTV) injection has provided a versatile alternative, being functional for more traditional modes of injection including split and splitless, but also permitting other techniques such as large volume injections with venting of solvent. Future developments will continue to expand on alternative injection procedures.We also predict an increasing trend towards the use of multidimensional GC. Although this is a more complicated technique, it enables the separation of very complex samples.

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