Abstract: Methods of identification of at least one most likely elemental composition of at least one species of molecules contained in a sample and/or originated from a sample by at least one ionisation process are provided. The method includes measuring a mass spectrum of the sample and may include reducing the measured mass spectrum to a neutral mass spectrum. The method further includes determining for a peak of interest a set of candidate species of molecules which have an expected peak with a peak position within a peak position tolerance range in the corresponding measured mass spectrum or neutral mass spectrum. An identification mass spectrum is identified for each candidate species and a range of peak positions is determined of all peaks of the identification mass spectrum. Two subscores of candidate species are determined by comparing the identification spectra with the measured or neutral mass spectrum and final scores are calculated from the subscores.

Abstract: Methods of identification of at least one most likely elemental composition of at least one species of molecules contained in a sample and/or originated from a sample by at least one ionisation process are provided. The method includes measuring a mass spectrum of the sample and may include reducing the measured mass spectrum to a neutral mass spectrum. The method further includes determining for a peak of interest a set of candidate species of molecules which have an expected peak with a peak position within a peak position tolerance range in the corresponding measured mass spectrum or neutral mass spectrum. An identification mass spectrum is identified for each candidate species and a range of peak positions is determined of all peaks of the identification mass spectrum. Two subscores of candidate species are determined by comparing the identification spectra with the measured or neutral mass spectrum and final scores are calculated from the subscores.

Abstract: A method and system for identification of microorganisms in a sample. The method includes processing the sample to produce at least one group of biomarker molecules from at least one microorganism in the sample, tandem mass-analyzing biomarker fragment ions from the at least one group of biomarker molecules to obtain a sample biomarker tandem mass spectrum of the biomarker, and identifying the microorganism in the sample based on a comparison of the sample biomarker tandem mass spectrum to an experimentally-derived reference tandem mass spectrum (stored in the reference library) from a known microorganism. The system includes a sample processing unit configured to process the sample and produce at least one group of biomarker molecules from at least one microorganism in the sample. The system includes a mass-analyzer for tandem mass analysis biomarker fragment ions.