asm 2016:针对质谱Tools for the Masses

Vicki Glaser

An overarching theme echoed by leading manufacturers of the instruments introduced at this year’s annual meeting of the American Society of Mass Spectrometry (ASMS) was notable for the dichotomy it represented: the evolution toward increasingly easy to use, hands-off MS systems that also continue to increase in technological complexity.

From June 5-9, in San Antonio, Texas, oral sessions, workshops, and poster presentations highlighted the expanding application range of MS in life sciences, food, energy, and health sciences research. The rapid adoption of MS in biomedical research has focused largely in the area of proteomics and metabolomics, biomarker identification, and drug discovery and development. Even as the leading vendors touted the sophisticated and unique capabilities of their newest technologies and products, and the novel types of applications they are enabling, their comments at ASMS underscored a shared goal:

MS should be a mainstream analytical research (and, in the not-too-distant future, routine clinical) tool that requires little to no special skills to perform.

The big picture that emerged from the scope of presentations was clear: the samples being analyzed, the questions being asked, the MS techniques being applied, and the ionization, detection, data acquisition, and other technology housed in the sleek boxes are all becoming more complex. In parallel, however, advanced software is being developed to create more user-friendly, fully integrated, and automated systems. The software is having an impact across the MS workflow – upstream to automate system set-up and calibration, sample preparation, and method development; and downstream to simplify data analysis and interpretation and results reporting.

“In the last 5-10 years, we have seen rapid acceleration of accurate mass technology, in the form of both GC-MS and LC-MS. Over the last 2-3 years the software, the workflow, is starting to catch up,” and “to unlock the power of the data,” Jim Yano, vice president of marketing, Mass Spectrometry Division at Agilent Technologies, tells us.

It’s About the Mass and the Masses

Ease of use and simplicity, combined with improved precision, reliability, robustness, and cost efficiency were common descriptors used by companies at ASMS. Whether they are developing integrated chromatography-MS systems for high throughput routine applications in analytical laboratories or meeting the growing need for high resolution accurate mass (HRAM) instruments in the research sector. Mark Roberts, product manager for Waters’ new Xevo® TQ-XS mass spectrometer, notes that more and more MS users have little experience with the technology. They tend to be technicians with Bachelor’s or Master’s degrees rather than Ph.D.’s with MS training. Thus, in designing the Xevo TQ-XS, Waters emphasized greater ease of use, combined with high throughput and features that would minimize downtime to improve productivity.

Thermo Fisher Scientific set out to make its Orbitrap MS technology more user-friendly for biotherapeutics applications, so it added a third scan mode and BioPharma software to create the all-in-one Q Exactive™ BioPharma MS/MS Hybrid Quadrupole-Orbitrap MS system. The Q Exactive BioPharma combines three protein characterization workflows in one instrument, says Jonathan Josephs, Ph.D., director of Marketing, Pharma/BioPharma, Life Sciences MS. These are intact protein analysis (e.g., for profiling antibody glycoforms in their native state); subunit and top-down analysis, with isotopic resolution; and peptide mapping of trypsin digests. Thermo Fisher extended the mass range of the new Q Exactive, enabling native MS analysis of therapeutic antibodies. The ability to perform structural analysis and monitor glycan changes is becoming increasingly important from a regulatory perspective to demonstrate consistent processes and products over time, according to Dr. Josephs.

Native MS allows greater m/z separation of charge states of complex co-eluting species such as ADCs.

Thermo Fisher also showcased 908 Devices’ ZipChip™ microfluidic capillary electrophoresis-based separation device that attaches to the front of its Orbitrap mass spectrometers. With no sample prep required, operators can load sub-microliter sample volumes into the chip-based device, which uses electrospray ionization (ESI) to deliver the sample directly off the chip into the mass spectrometer.

Mobilizing Ions

离子迁移技术的进步display at ASMS. Bruker launched the timsTOF™ MS, featuring Trapped Ion Mobility Spectrometry (TIMS) coupled to the company’s high performance QTOF instrument. TIMS provides ion mobility resolution >200 to improve the separation of isomeric compounds and the accuracy of collisional cross section (CCS) data, and to support studies of protein conformation and aggregation. TIMS can resolve two species that differ by <1.0% in mobility. It controls ion movement through two mechanisms: gas flow that pushes ions in one direction; and an electric field that acts in the opposite direction, trapping the ions.

Frank Laukien, PhD, President and CEO of Bruker, called attention to the Ion Mobility Expansion (imeX™) feature of TIMS and its value for analyzing complex mixtures, such as in metabolomics research. This feature allows users to adjust the ion mobility resolving power to meet research or analytical needs.

Christian Bleiholder, Ph.D., Assistant Professor, Florida State University, referred to TIMS as “more of a structural elucidation technique than a separation technique.” He described its use to screen Alzheimer’s disease drug candidates for their ability to eliminate the fibrillar oligomers that comprise amyloid lesions in brain tissue.

Dietrich Hauffe, Ph.D., executive vice president, Business Area Life Science Mass Spectrometry, at Bruker told us that TIMS evolved out of the company’s research group based on the needs of customers working in diverse areas, including polymer analysis, therapeutic drug development, and high throughput proteomics. The emphasis was on combining acquisition of accurate mass measurements and CCS values to obtain structural information, and capturing all of the ions generated.

“We’re already taking the technology to the next level,” says Hauffe, and looking at “how we can manipulate ions going through TIMS.” Bruker is also exploring the use of TIMS with whole cells as well as potential clinical applications.

The ion mobility technology within Waters’ Xevo TQ-XS instrument gives it the ability to resolve co-eluting isomeric metabolites. The Xevo TQ-XS uses Waters’ T-wave technology to move ions through the system and incorporates the newly designed StepWave™ XS technology, which generates a smaller, more focused ion beam that yields 2x-10x increased sensitivity depending on the analyte. The addition of horizontal plates to the StepWave design creates a shallower voltage gradient, promoting broader ion capture from the gas flow into the mass analyzer. Waters also extended the dynamic range of the XDR detector used in the Xevo TQ-XS to avoid saturation with high concentration analytes, and added tool-free probes on the ESI and APCI ion sources. Finally, this new member of the Xevo product family has a faster analysis speed at 500 transitions per second.

UniSpray provides improved sensitivity for 10 μg/kg fenpropimorph in green tea allowing for increased flexibility to dilute matrix without impacting analyte detection.

Introduced as an option for the Xevo TQ-XS was Waters’ new UniSpray™ ion source. The UniSpray unit can be mounted onto the mass spec in place of the standard ion source, providing multiple ionization mechanisms suitable for different MS methods without having to change ion sources. You want to “ionize as much as possible in a single pass” to ensure you are seeing everything, says Ed Sprake; to “expand chemical space” and “cover more polarity.”