neutral_losses_ESI: neutral_losses_ESI

Description Usage Format Details Source Examples

Description

A data table defining neutral losses in LC-ESI-MS (positive mode).

Usage

1
data("neutral_losses_ESI")

Format

A data frame with 45 observations on the following 3 variables.

Name

a character vector containing the fragment name used for plot annnotation

Formula

a character vector containing chemical formulas

Mass

a numeric vector containing the mass according to Formula

Details

The data frame consists of two character columns ('Name' and 'Formula') and the numeric column 'Mass'. In a mass spectrum peak pairs are analyzed for mass differences similar to the ones defined in neutral_losses. If such a mass difference is observed, we can assume that the according 'Formula' is the true neutral loss observed in this spectrum. In a plot this peak pair would be connected by a grey line and annotated with the information from 'Name'. In formula evaluation this peak pair would be used to limit formula suggestions with respect to plausability, i.e. if mass fragments A and B exist with mass difference 16.0313 than we can assume that the respective sum formulas have to be different by CH4. In consequence we can exlude sum formula suggestions for B which do not have a valid corresponding sum formula in A and vice versa.

Source

This list has been put together mnually by Jan Lisec analyzing multiple LC-ESI-MS (positive mode) data sets.

Examples

1
2

Example output

'data.frame':	45 obs. of  3 variables:
 $ Name   : Factor w/ 45 levels "C2","C2H2","C2H2O",..: 29 32 45 34 43 42 1 2 38 40 ...
 $ Formula: Factor w/ 45 levels "C1H1N1","C1H1N1O1",..: 3 6 45 8 43 42 14 16 1 12 ...
 $ Mass   : num  14 15 16 16 17 ...

InterpretMSSpectrum documentation built on May 2, 2019, 11:05 a.m.