Technology Forum: Capillary Electrophoresis

A powerful separations technique with minimal solvent usage, capillary electrophoresis is garnering increased attention as the ACN-shortage continues to influence the field of analytical chemistry. And with more powerful, automated instruments making this technique more accessible than ever, the future for CE is bright.

Joining us for this discussion are Kevin D. Altria of GlaxoSmithKline R&D; William Ciccone of MicroSolv Technology Corp; and Brian Nunnally of Wyeth.

What are some new trends/developments that you have noticed regarding CE?

Altria:There is a marked drive in pharmaceutical companies towards biopharmaceuticals, which is an area where CE has much to offer in terms of assays and characterizations. CE has become a mainstay analytical technique for biopharmaceuticals, whilst CE has struggled to replace HPLC for analysis of conventional small molecule pharmaceuticals. I would, therefore, expect an increase in CE usage within pharmaceutical companies, who are one of the main purchasers of CE systems.

CE equipment suppliers have recognized the need for improved robustness and reliability. They have built-in equipment improvements in recent upgraded systems based on customer feedback. There is also a trend towards well-controlled and validated chemistry/capillary kits to improve performance, for example, in inorganic anions and metal ion determinations.

Ciccone: CE is being used more and more for the analysis of ions such as Fl, Cl, and Br, etc.

Nunnally:There is a lot of interest in cIEF. At the CEPharm meeting, held every October, there has been an explosion of papers and posters on the use of cIEF. It has become an excellent technique to characterize your biomolecules.

I would have thought some of the miniaturization work would have taken off more than it has. For a while, everyone was talking about chip-based analyses. I have not seen a lot recently, so I can only suspect not much is being done on this.

What is the future of CE?

Altria:The use of CE for small inorganic anion and metal ion analysis will increase significantly and I expect will take over more of the workload of ion-exchange chromatography. Chiral analysis by CE is well established and will be increasingly routinely applied. Improved equipment design will improve robustness and reliability, leading to higher overall uptake of the technique. The use of multiplex (operation of multiple capillaries at the same time) massively increases sample throughput (e.g., 64 determinations per run) and see important utility in screening and characterization activities (e.g., determination of pKa, solubility, etc). Dedicated equipment and associated kits/capillaries will be applied to specific analysis – in particular, protein characterization/assays.

Ciccone:It seems that CE will remain a minor technique that is used largely by protein scientists and for the easy analysis of anions, cations, and chiral compounds by analytical chemists.

Nunnally:With the increasing interest in biotechnology and biologics, CE has a bright future. There are analyses for these molecules, which cannot be done by any other technique. Since the methodology is simple and method development is straight forward, I see more and more people using the technique. There will come a time, quite soon I imagine, where there will be no more SDS-PAGE or IEF gels. CE is far superior to either of these techniques; it boggles the mind why anyone still runs them! For areas where HPLC is possible, I see CE as a complementary or orthogonal technique. I am not one of those folks who thinks CE will (or should) replace HPLC. CE belongs in the toolbox of every scientist who is serious about understanding biologic compounds.

Has the economic climate had a profound effect on the CE market?

Altria:There are inherent cost savings in CE due to the reduced need for sample pretreatment and avoidance of organic solvents compared to HPLC. The use of generic method conditions can also reduce method development times. There is some increased attention being paid to CE due the solvent savings in this current acetonitrile shortage. The cost reductions only really come into reckoning if the equipment is reliable – downtime or need for repeated analysis quickly eliminate any potential cost savings – hopefully the equipment improvements I mentioned will improve this equation.

Ciccone:No, CE is routinely used in QC and R&D and the economic climate has not slowed its use.

Nunnally:I expect it has. I am sure the instrument vendors will tell you it has. I see lots of companies limiting their capital purchases and cutting back on staff. This has to have an effect on the number of instruments being sold and the supplies being purchased. As the economy improves, I expect the CE market to take off with it.

What obstacles do you see for the further development of CE?

Altria:The level of training and operational knowledge is still a primary barrier to CE being more widely utilized. This has improved in recent years as CE is now routinely taught in college courses, but the day-to-day routine operating knowledge and support is often missing within companies. This lack of knowledge can lead to poor methods being developed which are not robust. These methods then perform poorly and give CE a poor reputation in that company. CE equipment vendors and scientists should be encouraged to publish more articles, and include further information on their websites, about routine CE applications and method optimization and control.

Ciccone: The lack of acceptance of scientists who are not aware of the great power, ease-of-use, and reproducibility of CE is an obstacle. As robust interfaces with mass spectrometers are developed, the obstacle of CE not being compatible with MS will be overcome. Other than that, it is simply acceptance.

Nunnally:The biggest obstacles I see are money and outdated thinking. CE is still in need of investment from instrument vendors (to continue to develop better and more robust instrumentation), consumables vendors (to continue to develop kits and reagents), and scientists themselves (develop novel methodologies and applications). The investment is not just money, but also time. The justification for the lack of investment, e.g., the small market size, is a self-fulfilling prophecy (or Catch 22 for the Joseph Heller fans). Without the investment, the technique cannot grow, but without the growth, no one wants to invest.

The outdated thinking is what really frustrates me. The misconceptions about CE still abound. Many people (I refuse to use scientist here since the perceptions are not data-based) still believe CE is a highly variable technique. This is simply not true. Modern instrumentation has eliminated most of the early variability issues. As with any technique, in the right hands, the variability is suitable for most purposes. Additional replication can address any other concerns (fast analysis times make this reasonable).

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