LAUSR

Abstract Calculation of isotopic distribution is a valuable but challenging task in biological mass spectrometry. An algorithm to simulate both isotope aggregated and fine structure is proposed in this paper. The algorithm generates isotopic distribution of a given molecular formula by vector manipulation and change-making strategy based on the concept of denomination system. Additional feature of the algorithm can provide isotope fine structure within an interested m/z window. The performance of the algorithm is evaluated by a number of testing molecules. It is shown that the algorithm is accurate and efficient, providing an alternative solution to the conundrum of isotopic distribution calculation. The program has been implemented as an interactive Matlab package, an independent GUI software, and an open-source Python package, which can be conveniently downloaded and installed.