Mass Spectra of Natural Sterols

POSITIVE AND NEGATIVE ION MASS SPECTRA OF RING - SUBSTITUTED NITROBENZENES

The 70 ev positive and negative ion mass spectra of ring-substituted nitrobenzenes were studied. The influence of the substituent group on the fragmentation modes of the molecular ions is discussed. The effect of pressure in the formation of negative ions was also studied. As expected, the ratio of fragment ions to negative molecular ions decreased with increasing pressure in ion source.

Length Spectra of Natural Numbers

Two numbers are spectral equivalent if they have the same length spectrum. We show how to compute the equivalence classes of this relation. Moreover, we show that these classes can only have either 1, 2 or infinitely many elements.

Modelling CDA mass spectra

We present the initial results from a simulation of ion behaviour within Cassini’s cosmic dust analyser (CDA) instrument, using an inhouse ion dynamics code. This work is to enable and enhance the detailed interpretation of dust impact ionisation mass spectra returned from the Saturnian system. Early work has already provided insights into the properties of the impact plasma in both lowand high...

accurate-mass spectra

Dereplication of peptidic natural products through database search of mass spectra

Peptidic natural products (PNPs) are widely used compounds that include many antibiotics and a variety of other bioactive peptides. Although recent breakthroughs in PNP discovery raised the challenge of developing new algorithms for their analysis, identification of PNPs via database search of tandem mass spectra remains an open problem. To address this problem, natural product researchers use ...