Sample

CHEMICAL DETAILS SAMPLE ORIGIN SAMPLE PREP./SIZE PYROL. CONDITIONS TOTAL ION COUNTS

RIBONUCLEIC ACID (RNA) (from baker's yeast)

Aldrich Chem. Corp. Inc., Milwaukee, USA suspension in methanol; 10 ng standard 3.5 X 104

remarks - As discussed in Part I, Section 3.3, Curie-point pyrolysis mass spectra of RNA are completely dominated by ribose moiety fragments (compare also with Spectrum C.2 (DNA)). Signals which can be ascribed to complete base moieties or base moiety fragments are absent due to the loss of more or less intact base moieties by condensation on the wall of the reaction tube with an exception of the peak at m/z 17 which may result from deamination of base moieties. Such base fragments become more prominent when the entire pyrolysate transfer line is heated (ref. 205) indicating that in the present spectrum the absence of such fragments is due to condensation losses. The marked peaks at m/z 110, 126 and 128 point to the presence of residual hexose impurities in this sample.

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