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Thermo Mass Spec Makes Splash at ASMS; Accessories for PTM Analysis Debut

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SAN ANTONIO — At this year's American Society for Mass Spectrometry conference, held here this week, Thermo Electron made a splash with the introduction of a new hybrid mass spectrometer that uses a novel type of mass analyzer.

Also debuting at the conference were new protein-labeling technologies and mass-spec accessories designed to improve the analysis of post-translationally modified proteins (see New Products table).

Thermo's new LTQ Orbitrap is based on a fundamentally new type of mass analyzer involving an electrostatic ion trap. The instrument is designed to analyze small molecules, including proteins, small drug molecules, and metabolites.

"The Orbitrap is not only for proteomics," said Lestor Taylor, Thermo's global product marketing director in life sciences and mass spectrometry. "It's for anyone doing metabolomics, structural identification — anyone who has a need for accurate mass" measurements.

According to Thermo, the new instrument allows researchers to work flexibly with complex mixtures. Taylor said the instrument is tailored towards pharmaceutical researchers working in drug metabolism, people working in metabolomics, researchers who are identifying post-translational modifications, and people doing bottom-up sequencing.

With a mass resolution of 60,000 at m/z 400 and a one-second cycle, and a maximum resolution of 100,000, the LTQ Orbitrap is not designed for top-down proteomics, Taylor said. The instrument is also not good for the analysis of mixtures, such as crude-oil extracts, that require extremely high resolution.

Priced at $625,000, the LTQ Orbitrap is a cheaper alternative to the LTQ-FT hybrid ion-trap fourier-transform high-resolution mass spectrometer, which costs about $800,000. Researchers who do not require the 400,000 resolution of the LTQ-FT may well consider the LTQ Orbitrap, Taylor said. In terms of speed, the LTQ Orbitrap is faster than the LTQ-FT, with an "extreme throughput" of three high-resolution scans per second.

"It's relatively uncommon to have a fundamentally new mass analyzer introduced to the market and we're really enthusiastic about this new [mass spec]," Taylor said. "The last time there was an introduction of a novel analyzer was 20 years ago."

Asked to comment on the LTQ Orbitrap, Tim Riley, vice president of proteomics business development at Waters, said the new instrument is very innovative, but it will not necessarily answer the questions that customers are investigating.

"The bottom line is, at the end of the day, is it going to give you the answer you need?" said Riley.

For its part, Waters' releases at this year's ASMS meeting included enhancements to its nanoAcquity Ultra Performance LC System that are designed to enhance throughput and ease of use. Riley said that now that Waters has firmly established its Acquity system as a front-end to mass specs, it is in discussions with other mass spec vendors to see if the Aquity system can be made more compatible with other mass-spec brands beyond Waters'.

Protein Labeling Technologies

Gaining popularity among proteomics researchers is a protein-labeling technology called SILAC, or Stable Isotopic Labeling using Amino Acids in Cell Culture [see story, this issue]. The technology, which is licensed by Invitrogen, works by incorporating special amino acids into proteins and peptides during cell growth. However, the technology, which was originally developed in Brian Chait's laboratory at Rockefeller University, was not commercially available until now.

Applied Biosystems and Invitrogen announced this week that they will be co-marketing SILAC reagents, which have been exclusively licensed by Chait to Invitrogen (see Protein Labeling story).

Bruker also introduced a new type of quantitative labeling technology called ICPL, or Isotope Coded Protein Label. The technology works by labeling lysine side chains. It was originally developed by Friedrich Lottspeich and Joseph Kellerman at the Max-Planck Institute, then licensed exclusively to the German consumables and electrophoresis company Serva Electrophoresis, which decided to expand its customer base by collaborating with Bruker.

Mass Spec Accessories

Both Agilent and Bruker introduced Electron Transfer Dissociation, or ETD, modules designed to be used with ion-trap mass specs to enable better analysis of post-translationally modified proteins and proteins sequenced de novo.

"Modern proteomics has moved beyond simple identification, and one of the primary goals of functional proteomics is now the unraveling of the many subtle modifications arising in proteins that are often very important for their biological activity," said Detlev Suckau, the head of proteomics applications development at Bruker Daltonics.

With ETD modules, ions are formed outside of the mass spec's ion trap, allowing the full mass range to be collected, and eliminating the one-third low-mass cutoff restriction typical of traditional Collision Activated Dissocation ion-trap analysis.

"With ETD, proteins are broken apart at about every bond. It's great for de novo sequencing, and it's ideal for post-translational modifications," said Laukien.

Thermo Electron also introduced a new mass spec accessory: a heated electrospray-ionization probe designed to work with the Finnigan TSQ Quantum Ultra triple quadrupole mass spectrometers. The probe increases mass spec sensitivity and selectivity.

— Tien Shun Lee ([email protected])