Resolution and Resolving Power

It is important to understand how resolution and resolving power are used in reporting mass spectrometric data. The terms resolution and resolving power are defined in some pubhshed lists as they are above, while in others the definitions are reversed. On occasion, the two terms are used interchangeably. Having multiple definitions can be confusing. 

GC-MS of the fluid inclusion oils can be performed on benchtop quadrupole, triple quadrupole, or sector instruments. The main criterion is sensitivity because such low amounts of oil are recovered from fluid inclusions, sometime lower-sensitivity instruments such as benchtop quadrupole instruments do not give sufficient quality data to be reliably interpreted. Further subordinate criteria are mass resolution and resolving power it helps to separate certain compounds using better than unit mass resolution and/or tandem mass spectrometry... 

Resolving Power and Resolution In Mass Spectrometry The resolving power of a mass spectrometer describes the smallest mass differences which can be separated by the mass analyser (Webb, 2004b). Resolution and resolving power in MS today are defined differently depending on the analyser or instrument type, and is often stated without the indication of the definition employed. The new fUPAC definitions of terms used in MS provide a precise definition. 

Mass Resolution and Resolving Power. Thermo Fisher Scientific,... 

Resolution or resolving power is the ability of a mass spectrometer, and in particular of its analyzer system, to separate ions with different m/z ratios. An example of mass spectra obtained at different resolutions is reported in Figure 2.1 by increasing the resolution the peak shape becomes more and more narrow thus allowing the separation of ions with their m/z values differing in decimals (10 1—10 3). 

Resolution (or resolving power) plays an important role in mass spectrometry for applications requiring the characterization of very similar chemical species. The ability to detect and accurately measure the m/z ratio of a particular ion depends directly on the resolving power of the mass analyzer. For example, if a sample contains two isobaric compounds (i.e., having the same nominal molecular mass but different elemental formulae) the difference in the exact masses of the molecular ions will be much less than 1 m/z unit. Any mass analyzer possessing a nominal resolving power (e.g., RP< 1000) will register only one peak in the mass spectrum of such a binary mixture. Attempts to measure the... 

Although the above mass spectrometric tools have mass ranges and resolving powers adequate for chemical analysis, mass spectral characterization and structural analysis of biopolymers generally demand efficient detection of ions over a wide mass range, accurate mass measurements, and high mass resolution. The FT-ICR analyzer is able to combine high resolution and MS" capabilities. ... 

The critical operational assumption that makes it possible to draw conclusions in a given comparison situation about the effect of plate and pore amount is that a constant volume and a constant absolute amount of solute was injected per column to normalize comparisons. If pore amount per column is constant, then increase in resolution with several columns of the same kind in series is due only to the increased amount of plates. Conversely, if plates of a column bank are the same, then differences in resolution are due to differences in the amount of pores of appropriate size. Also, all the other appropriate operating parameters are constant for each comparison. The following group of comparisons will illustrate different issues involving the interplay of pores, plates, and resolving power. The times on the figures are maximum values for total permeation volumes at a flow rate of 1 ml/min. 

It is important to realize the difference between accurate mass determination and resolving power. Accurate mass can be determined at a quite low resolution but requires an isolated peak, and thus applies safely only on a high-quality spectrum of one pure compound. Risks of having mixed peaks, that is peaks of compounds having the same nominal mass but different elemental compositions, with pure compounds still exist for the... 

Figure 3.3-17 Relation between the optimal spectral band width Ai>o = t /Rp and the line width AC i/2, Rq is the resolving power of the spectrometer. For a the sensitivity is low since the spectral band width is larger than the line width, also the background contributes to the noise, for b the resolution of the spectrometer is sufficient to yield a high sensitivity, c Relation between bandwidth and resolving power.

In summary, the sensitivity and resolving power of flow-driven planar FAIMS at moderate ion current scale as the inverse exponent and square root of separation time ties, respectively. These laws allow predicting many aspects of analyses without simulations and permit their validation when simulations are needed. The variation of ties via adjustment of flow rate is an effective practical approach to control of planar FAIMS resolution. In strongly curved gaps, ties is less important and other instmmental parameters make a greater difference (4.3). 

Resolution. The resolving power of the device, although comparable with that of some published drift ceU results, falls short of that obtained with specialized in-house developed DCIMS instruments and, in particular, atmospheric pressure devices. 

Figure 5.2 Comparison of linear and reflectron time-of-flight MALDI-MS for the analysis of oligonucleotides of length up to 60 nucleotides. For shorter oligonucleotides up to 25mer length (ca. 8000 Da), higher resolution (mass resolving power of 15 000) and mass accuracy (10-50ppm) can be achieved with reflectron TOF. At higher...

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