Subtraction algorithms provide users with a greater flexibility to select between multiple subtraction methods based on the mass accuracy of their data and the stability of their mass spectrometer
Advanced Chemistry Development (ACD/Labs) is introducing extended features for processing mass spectra in MS Manager, including a number of spectral subtraction, mirroring, and normalisation capabilities that it says will allow users to compare and contrast mass spectra in an precise, yet flexible manner.
Three main types of quantitative subtraction methods have been added to the MS Manager processing environment to help ensure more accurate results, including m/z, intensity, and interpolation-based subtraction.
Mark Bayliss, director of analytical informatics for ACD/Labs, states: "Spectral subtraction techniques have been available for many years in different software platforms.
"In line with the heterogeneous data types that MS Manager is compatible with, the necessity for flexible algorithms for subtraction is a must and provides capabilities to suit an extremely wide range of applications for which this functionality may be used.
"Its application to top-down proteomics has been one such example of its usage".
While previous versions of MS Manager allowed users to subtract one mass spectrum from another, the new spectral subtraction algorithms introduced in version 8.2 and later provide users with a greater flexibility to select between multiple subtraction methods based on the mass accuracy of their data and the stability of their mass spectrometer.
In addition, users may apply a qualitative Boolean subtraction option to remove all common peaks between spectra, or a single peak option to remove all major peaks in the mass spectrum.
These enhanced subtraction capabilities were recently used by researchers at the US Food and Drug Administration to quickly and objectively identify potential protein biomarkers between two closely related strains of E coli.
This application showed a significant time saving over other manual and computational approaches, says the company.
It also says that new spectral mirroring and normalisation functions in MS Manager, when used in conjunction with the enhanced subtraction capabilities, make it even easier to find differences between mass spectra.
The spectral mirror format displays one mass spectrum as a reflection of another, along the same X-axis, for easy visual comparison, especially in the determination of low intensity spectral differences.
Mirrored spectra can then be normalised to the intensity of one selected peak so that viewing small peaks in the spectrum can be achieved swiftly and with ease.
Bayliss adds: "Spectral mirroring and normalisation capabilities within MS Manager provide clear and easy to use visualisation tools for the detailed assessment of spectra, for example, after a series of spectral subtraction approaches.
"These additions further complement the tools that are typically used during spectral analysis and spectral elucidation studies using mass spectrometry, bringing value through time saving and flexibility of data analysis".
MS Manager is part of SpecManager, the overall spectroscopic processing and data management system that consolidates structure, spectra, and other analytical data from any technique into a single platform for unified analysis and dissemination throughout the enterprise.
This system facilitates the interlinkage of chromatographic and spectral data, providing a consolidated way to store work-in-progress analytical data and compound reference information.
