Resolution definitions

The chemical world is often divided into measurers and makers of molecules. This division has deep historic roots, but it artificially impedes taking advantage of both aspects of the chemical sciences. Of key importance to all forms of chemistry are instruments and techniques that allow examination, in space and in time, of the composition and characterization of a chemical system under study. To achieve this end in a practical manner, these instruments will need to multiplex several analytical methods. They will need to meet one or more of the requirements for characterization of the products of combinatorial chemical synthesis, correlation of molecular structure with dynamic processes, high-resolution definition of three-dimensional structures and the dynamics of then-formation, and remote detection and telemetry. 

In quadmpole and ion trap spectrometers, it is customary to use the unit resolution definition, which means that each mass can be separated from the next integer mass (500 from 501, 2000 from 2001, etc.). The comparison and conversion between the different resolution definitions is not trivial, considering that they are strongly dependent on peak shape (Gaussian, triangular, trapezoidal, Lorent-zian, etc.).9... 

The side chain dihedral angle Xi is important for high-resolution definition of protein structures as it determines the angle at which each amino acid side chain branches out from the protein backbone. Moreover, in combination with certain types of NOEs, it can allow stereospecific assignment of prochiral /3-methylene protons, which improves the precision of NMR structures by obviating the need to include pseudoatom distance corrections.140-142... 

FWHM Full width (at) half maximum (height) (resolution definition)... 

Improving the mass resolution (definition is covered in Section 5.1.1.1.1) reduces this m/q spread, thereby allowing for the separation of secondary ion signals of similar (nominal) m/q ratios. Minimal spread is noted in the FT-ICR mass spectra shown in Figure 5.2(c) where an extremely High Mass Resolution (HMR) was used (Smith et al. 2013). 

Figure 5.3 Mass resolution definitions referred to as the (a) single-ion method and (b) the double-ion method for flat-top peaks. The same definitions apply to round topped peaks.

ISO 12233 2014 photography—electronic still picture imaging—resolution and spatial frequency responses Definition and measurement of spatial frequency response, visual resolution, definition of MTF parameter... 

The resolution (MTF) and sharpness measurement in a CMS has to be evaluated as an integral performance of the whole CMS system. And the requirements are defined according to the orientation of interest and not necessarily referencing to the actual full image height as is the case of ISO 12233 2014 definition. Therefore, when the [LW/PH] unit is used, there are several aspects in which the definition had to be modified compared to the resolution definition under ISO 12233 2014. 

Figure 2.172 (a-c) Comparison of different mass resolution definitions 10% valley (equal to 5% peak height) and FWHM (Munster and Taylor, 2009). 

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