ASMS 2009 Product of the Show

IBO has selected Thermo Scientific’s LTQ Velos ion trap LC/MS as the best new product at this year’s ASMS meeting. While the exterior design of the new instrument is essentially identical to other LTQ models, Thermo has made some considerable advances in the mass analyzer and other internal components.

At the core of the LTQ Velos is a new ion trap mass-analyzer design that splits the linear ion trap into dual pressure zones. The first ion trap cell is operated at a higher pressure than conventional single-cell mass analyzers, which allows for a more optimal pressure for ion trapping, isolating and fragmenting. The second cell is operated at a lower pressure, which is more optimal for mass analysis. The decoupling of ion manipulation and analysis eliminates the need to operate the mass analyzer at a pressure that is a compromise between optimal pressures for either function.

Thermo claims that this new configuration improves ion trapping efficiency from around 60% to around 90% and can raise Collision Induced Dissociation efficiency from less than 70% to over 80%. The lower pressure of the second cell can improve resolution from 0.7u FWHM to 0.45u FWHM. However, most of this resolution gain has been traded off to provide a doubling of the scan speed to 33,300 u/second, which Thermo engineers believed was more important.

Another improvement in the Velos version of the LTQ is the S-Lens ion optics, which provide yet another improvement in ion transmission efficiency from the ion source to the mass analyzer. Thermo claims this provides an improvement of 5 to 10 times in the sensitivity of previous-generation instruments.

While ion optics tend to be improved on most new MS models, it is the dual-pressure ion trap design that is quite innovative. This could provide a major jump in ion trap performance, as well as providing inspiration for future ion trap mass analyzer designs.

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