What's New in Mass Spectrometry?

Last summer got off to a hot start at the June 2005 American Society for Mass Spectrometry meeting in San Antonio, Texas.

Aileen Constans
Sep 25, 2005
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Courtesy of Waters Corporation

Waters' Quattro Premier XE Mass Spectrometer

Last summer got off to a hot start at the June 2005 American Society for Mass Spectrometry meeting in San Antonio, Texas. With new product releases ranging from labeling reagents for quantitative proteomics to breakthrough hybrid mass spectrometry technology, a variety of companies took advantage of the large gathering of potential customers to introduce their wares. This roundup highlights several new and noteworthy offerings.

BUZZWORTHY MASS SPECTROMETERS

Thermo Electron http://www.thermo.com of Waltham, Mass., released the LTQ Orbitrap, a hybrid tandem instrument combining a linear ion trap mass spectrometer with a new Fourier transform (FT) mass analyzer called an Orbitrap (see related story, page 20). Invented by Alexander Makarov in the late 1990s, the Orbitrap is the first new mass spectrometry technique to be commercialized within the last 20 years, says marketing manager Helmut Muenster.

John Yates of The Scripps Research Institute in La Jolla, Calif., who gave a presentation on the instrument at the conference and plans to purchase two of them, says the product "caught everybody by surprise – a lot of people knew about the technology, but they weren't expecting a commercial product out of it for a couple more years."

Orbitrap technology is similar to that of an ion cyclotron resonance (ICR) mass spectrometer, in which ions move about an electrode and have to move quickly over long distances without bouncing into other molecules, says Yates. "It requires a very high vacuum in order to be successful.... That tends to be kind of tricky technology, [because] you have to interface that with the linear ion trap, which operates at very low vacuum," he explains.

But though its performance is close to that of an FT-ICR mass spectrometer, with a resolution of 60,000 to 100,000 FWHM and a mass accuracy of less than 5 ppm with no internal mass calibration, the Orbitrap has several advantages, he notes. "It's cheaper. You don't have to deal with a high-field magnet, which requires liquid nitrogen and liquid helium," Yates says. According to Muenster, the difference in price between Thermo's Finnigan LTQ-FT mass spectrometer and the LTQ-Orbitrap (list price, $625,000) is about $200,000. It also has lower space requirements because it does not require the high ceiling necessary for housing a magnet.

Waters Corp. http://www.waters.com of Milford, Mass., presented another high-end instrument, the Quattro Premier XE, a tandem quadrupole mass spectrometer designed for use with the company's ACQUITY UPLC technology. Product manager Steve Smith says Waters realized many customers using UPLC for quantitation wanted to look at positive and negative ions at the same time. "[The instrument] allows you to look at both positive and negative ions across a narrow UPLC peak without reinjection as it can rapidly switch polarity, typically 10 times a second," says Smith. Previous instruments would have taken seconds, if they could do the switching at all, he adds.

The Quattro Premier XE has a list price of approximately $330,000–$340,000 for the basic system (without the ACQUITY UPLC).

BIOMARKER BONANZA

Boston-based PerkinElmer Life and Analytical Sciences http://las.perkinelmer.com announced its BioXPRESSION platform for biomarker discovery and screening. According to Mary Lopez, business leader for analytical proteomics, the platform consists of three technologies designed to facilitate the discovery of diagnostic patterns for disease.

The first is a high-throughput sample-preparation method that uses membrane absorbers to capture abundant carrier proteins such as albumin, and a proprietary chemistry (developed by partner Vivascience of Hannover, Germany) to release low-abundance biomarkers that are associated with the carrier proteins directly onto a MALDI plate, leaving the carrier proteins behind.

The platform's other components are PerkinElmer's high-resolution prOTOF mass spectrometer, which can acquire spectra over a broad mass range (700–10,000 daltons) in one acquisition, and new biomarker analysis software developed with partner companies Nonlinear Dynamics and Predictive Diagnostics, to handle the resulting data. Lopez says the company has a paper in press describing the platform's use for the discovery of a diagnostic pattern for Alzheimer disease.

ALTERNATIVE TO ICAT

Bruker Daltonics http://www.bdal.com of Billerica, Mass., introduced kits for ICPL, a stable isotope labeling technique developed by Serva Electrophoresis of Heidelberg, Germany, for quantitative proteomic analysis. ICPL, says Detlev Suckau, head of proteomics at Bruker, is an alternative to ICAT. ICAT is a differential labeling method that allows researchers to directly compare two mass profiles in a single run of the mass spectrometer. Whereas ICAT targets cysteine residues, which are low in abundance, ICPL uses an NHS-ester-based chemistry to label more abundant lysine side chains along with the protein N-terminus with high specificity, he says.

Another advantage, says Suckau, is that ICPL labeling is done at the level of the intact proteome; the two samples to be analyzed are labeled first, combined, fractionated, and then digested. In ICAT, the proteins are digested before the resulting peptides are labeled, potentially introducing errors because the two samples are digested under different conditions, Suckau says.

Bruker Daltonics, which is comarketing ICPL with Serva, offers software to support quantitative proteomic analysis with the ICPL kits.