GC/GC–MS

From the recent and well-publicized food safety and lead paint scares to the current debate over carrier gas, the field of GC and GC–MS research remains as vital and relevant as ever. Our experts discuss this workhorse technique and its vital role in the separations community.

Joining us for this discussion are Kory Kelly of Phenomenex; Nicholas H. Snow of Seton Hall University; and William Goodman and Adam Patkin of PerkinElmer, Inc.

What trends have you most intrigued in the GC/GC–MS field?

Kelly:The recent economic situation has affected everyone with labs looking to do more with less. The labs we talk to are looking to optimize methods so the same analyses can be done in much less time – and with additional compounds. One answer to this is to convert methods to “fast GC” by using shorter columns with smaller internal diameters that have the same column efficiencies as longer and wider bore columns. To support this trend, we have focused on offering more columns in fast GC dimensions as well as providing application support for switching to these columns.

Snow:I am especially interested in the possibilities for GC, GC–MS, and GCxGC-MS in biological, clinical, and metabolomic analysis. Especially, the unparalleled separation and detection power offered by GCxGC-MS offers great advantages in the analysis of complex samples found in drug and metabolite applications. The possibilities are especially powerful if GC–MS or GCxGC-MS are combined with on-line extraction techniques such as solid phase extraction, micro-traps, or SPME.

Goodman and Patkin:An interesting and important trend is the continued demand for more information from rapid analyses. Laboratories are using multiple detectors, multidimensional separations, and hyphenated techniques to get more data, faster.

Applications which used to be GC only, such as blood alcohol using static headspace/GC/FID are with increasing frequency splitting the effluent to a MS for unambiguous target identification and tentative identification of unknown peaks.

Simple, robust micro-channel front-end technologies for column flow switching are enhancing the separation power of the GC.

Also, GC and GC–MS are being combined with other techniques such as thermogravimetric analysis (TGA) and ICP-MS to provide enhanced resolution and identification capabilities.

What is the GC/GC–MS application area that you see growing the fastest?

Kelly:The two applications areas we see growing the fastest are environmental and food safety applications, especially in emerging markets such as India and China. The recent melamine incidents have drawn a focus to imported goods. Emerging countries are eager for information and techniques to show that products and pollution levels are compliant with existing and evolving regulations.

Snow:Recently, the rise of GCxGC has mostly been fed by petroleum and related environmental analyses. GCxGC-MS opens up many other possibilities. I see GCxGC-MS being applied to analyses traditionally done by GC–MS such as drugs of abuse and clinical analysis and into more complex environmental and food or flavor analysis methods. As I mentioned above, we have really just scratched the surface of possibilities for GC in drug and metabolite analysis. GC remains the technique of choice for nearly all volatile compound analysis. Improvements such as inexpensive PTV inlets, more inert columns and instruments and miniaturization of components should extend the range of compounds considered volatile enough for GC.

Goodman and Patkin:The application area growing fastest for GC and GC–MS is quality and safety testing of food and consumer products on a broad scale. This type of testing includes many different types of samples with a wide variety of potential contaminants or adulterants.

GC–MS is uniquely suited for this type of application as a result of the ability to identify unknowns with the aid of large, trusted mass spectral data libraries. In addition to GC–MS, the sensitivity and specificity of GC detectors such as ECD, NPD, and FPD are often critical in the determination of specific low-level analytes, such as pesticide residues.

What obstacles stand in the way of GC–MS development?

Kelly:The GC market is a relatively mature field and more new methods are being developed on LC–MS-MS because it offers better sensitivity or faster run times than current GC methods. With the increasing budget constraints brought on by the global economic crisis, labs have to make tough decisions about where to spend their money. To remain competitive GC–MS will have to continue to improve the speed and sensitivity of the instruments. To support this, we are focused on developing columns that provide even lower bleed levels to improve quantitation at low levels. We are also working very closely with key customers to design better phases for challenging separations such as drugs of abuse.

Snow:As with most instruments, cost, complexity, inertia of older methods, and education of potential users provide the biggest obstacles to GC, GC–MS and GCxGC-MS. Especially in the current economy, companies will require strong cost-benefit arguments before the capital investment in new GC–MS equipment. A lot of companies continue to get by with older GCs. (I have a 5890 GC that was built in 1987 still running.) To overcome these obstacles, instrument manufacturers should be especially aggressive in promoting research and education that help their potential customers justify new investments. There is a general shortage of skilled GC and GC–MS operators that will need to be overcome through education of more scientists in separation science.

Patkin:The major technological obstacle to GC–MS is noise. There have been significant advancements over the last few years in eliminating background noise through ion optics, electronics, and software. Improving signal-to-noise without a significant cost increase continues to be an area of active research.

Do you expect any major developments to be presented at Pittcon 2010, or other major shows?

Kelly:I don’t expect any major product developments to be presented in the short term as it relates to systems. Although, it will be interesting to see the impact of the Agilent/Varian acquisition on both instrument and software design and capabilities after the merger is approved. It will also be interesting to see if one manufacturer can successfully support four major brands of GC columns. My company will continue to launch new and innovative solutions. We have several new products in the works that will greatly improve some of the current application challenges.

Snow:I expect that there will be various incremental improvements over the next few years. The basic technologies for GC–MS are proven and demonstrated to work very well. Most instruments still need some engineering to make operation and maintenance simpler and to reduce the use of consumables so new devices will continue to be introduced each year. Current users should plan to attend a show and see new developments side-by-side; new users will be impressed with the changes since they last evaluated GC or GC–MS or learned about them in a class.

Goodman:Yes, we expect new developments to be presented at Pittcon and other important conferences such as ASMS. However, this information is unavailable to the public until just prior to the show.

What is the future of GC/GC–MS?

Kelly:The near future of GC/GC-MS will be a focus on optimizing the current analysis for things such as speed, resolution, and method ruggedness. The optimization of current methods will offer time and cost saving benefits that will help to further development in GC. Cost-per-sample and lab productivity will continue to be major drivers until the economic conditions improve.

Labs will also focus on application-driven solutions that provide a complete answer to a specific analysis. These turnkey solutions will include optimized sample preparation, as well as chromatography methods. My company has been actively developing specialized solutions to common problems for established markets like drugs of abuse, pharmaceutical, and environmental testing to emerging industries like food safety and biofuels. We understand the needs of these labs and are doing our best to provide real solutions that can be implemented quickly.

Snow:GC and GC–MS have a very bright future. New development such as ionic liquid columns will make the study of selectivity and tuning of selectivity to specific applications possible. Over the past 20 years an interesting trend in capillary columns emerged. When fused-silica capillary columns were first introduced, selectivity was not a major issue, as there were so many more theoretical plates than in traditional packed columns. Now, with basic column materials well proved, the emphasis has shifted toward selectivity for the most difficult separations. GC will continue to be a strong technique as long as there are relatively small molecules that need to be separated faster, better, and with lower detection limits.

Patkin:The future is very strong as evidenced by increasing demand. The market is demanding more sensitive instruments that are faster, less expensive, and easier to use. The analysts are less experienced in, and have increasing levels of, responsibility for other analyses. GC and GC–MS needs to be “smarter.” Several years ago the concept of “chemist in a box” was popular – an analytical instrument with software smart enough to tell the user when the data meets required QA/QC criteria, coupled with self diagnostics sophisticated enough to work with the customer to resolve most instrumental and method-related problems without having to call in an expert. While not yet implemented, this is still required.

Most quadrupole GC–MS systems can now scan over 10,000 u/s and 50 scans/s for compatibility with “fast GC.” The ongoing challenge is to maintain good mass peak shape and resolution, since the MS is scanning so fast that the ions may not have enough RF cycles in the rods to be well-filtered.

What is one change/improvement you hope to see in the GC/GC–MS industry over the next few years?

Kelly:There are a few changes that would make GC more competitive with alternative techniques. Newer techniques such as GCxGC have sparked new life into GC analysis, but have yet to find a real routine application area. Improvements in system design to support fast GC are important such as: faster scan rates for MS, improved pneumatics to offer better control for at higher pressures or lower flow rates, and faster heating and cooling to offer shorter cycling times. However, in the past several years, it’s been the consumable manufacturers pushing the GC and GC–MS markets forward. It will be interesting to see what the instrument manufacturers develop in the next several years to help launch GC to the next level.

Snow:The biggest challenge in GC, GC–MS, and separation science in general, is the education and training of users. Undergraduate training in separation science still lags far behind its use throughout industry. Postgraduate training is generally on-the-job and is geared toward specific techniques and methods that are used in individual workplaces and not to general and fundamental education for all techniques. There is a clear shortage of broadly and fundamentally trained separation scientists and an even greater shortage of qualified professors to teach them.

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