Molecular secondary ion mass spectra of bio-organic compounds.

Molecular secondary ion mass spectra of kanamycins.

Sir: In our laboratories two strategies for obtaining mass spectra of involatile and/or thermally unstable natural products have been used. One is an optimization of sample vaporization, which involves rapid sample heating followed by thermal desorption and ionization under chemical ionization (CI) conditions, that is emitter CI mass spectrometry (emitter CIMS). Recently, we have reported a pre...

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.

Reduction in liquid secondary ion mass spectrometry. Comparison of the fission fragment and liquid secondary ion mass spectra of organic dyestuffs.

Mass spectral characterlzatlon of the Intact chromophore of organic dyestuffs, frequently prepared as salts, Is relatlvely faclle wlth desorptlon lonlratlon. The mass spectra obtalned, however, may show the presence of chemlcally altered forms of the chromophore. Comparlson of the flsslon fragment (FF) and llquld secondary Ion mass spectra (Ilquld SIMS) of a serles of dyes reveals enhanced (C +...

ATR spectra database of organic compounds

A spectral database of 100 attenuated total reflectance Fourier transform infrared spectra is created. The software IRSS previously developed in our lab is used to perform spectral search in the database. Despite the slight difference between the absorption and ATR FT-IR spectra, the comprehensive test search sessions of ATR spectra in IR libraries and vice versa (absorption spectra searched in...

Organic and Bio-molecular Chemistry