Principal components scores and loadings plots for visualisation of the electrospray ionisation liquid chromatography mass spectra of a mixture of chlorophyll degradation products at different cone voltages

Positive ion electrospray liquid chromatography mass spectrometry was perfo rmed on a mixture of allomers obtained from the degradation of chlorophyll a, at three cone voltages. An approach is described for obtaining principal components loadings and scores plots, involving mass selection, normalisat ion and standardisation of the data, principal components analysis and thre e dimensional projections. The loadings plots group ions which are assigned to five major compounds in the mixture by reference to the scores, At high er cone voltage fragmentation and differentiation between compounds with id entical molecular weights is observed. Copyright (C) 1999 John Wiley & Sons , Ltd.