Molecular secondary ion mass spectra of kanamycins.
نویسندگان
چکیده
منابع مشابه
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...
متن کاملPOSITIVE 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.
متن کاملQuantitative Secondary Ion Mass Spectrometry
mental standards, and by statistical and systematic errors in the measurement of x-ray lines and in the separation of line intensity from spectral background. The errors in estimating the characteristics of the detector system, with exception of deadtime effects, cancel when the emission from the specimen is divided by that from the standard. The estimate of achievable accuracy of EPMA and the ...
متن کاملLiquid Secondary Ion Mass Spectrometry
Liquid secondary-ion mass spectrometry (liquid SIMS) is an obsolescent ionization technique that revolutionized the analyses of large biological molecules in the 1980s. The term includes fast atom bombardment mass spectrometry (FAB-MS). The technique has been largely superseded by electrospray ionization. This account will cover the history of the technique, the principles of the operation, and...
متن کاملReduction 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 +...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: The Journal of Antibiotics
سال: 1982
ISSN: 0021-8820,1881-1469
DOI: 10.7164/antibiotics.35.102