Page 382 - Tandem Techniques
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The micro-electrospray interface was used to monitor the separation of a number of polypeptides and an
example of the separation obtained from 2 pmol of sample is shown in Figure 9.26.
It is seen that very similar chromatograms are obtained, and little or no loss of chromatographic
resolution takes place in the micro-electrospray interface. The sample size was 2 pmol which, if a mean
molecular weight of 1000 is assumed, will represent a sample mass of about 2 ng. However, a better
example of the sensitivity obtainable from the system is afforded by the reconstructed chromatograms
shown in Figure 9.27. The sample size was only 40 fmole, which, again assuming a mean molecular
weight of about 1000, would be equivalent to a sample mass of 40 pg.
Figure 9.27
Selected Mass Chromatograms for Three of the Peptides
from a Sample of Lys C Digest of Cytochrome
Reprinted with permission from J. Via and L. T. Taylor, Anal.
Chem., 66(9)(1994)1385, Copyright 1994 American Chemical Society
It is seen that the combination of the microbore column and the microelectrospray provides a very high
sensitivity without compromising the performance of either the liquid chromatograph or the mass
spectrometer.
