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extract. (B) is the computer reconstructed mass chromatogram of the ion at an m/z value of 568, which
corresponds to lutein. (C) is the computer reconstructed mass chromatogram of the ion at an m/z value
of 552, showing the isomers of ß-cryptoxanthin. (D) is the chromatogram provided by the output of the
diode array UV detector at 450 nm, recorded during the analysis shown in (A). (E) is the chromatogram
provided by the output of the diode array UV detector at 450 nm, recorded during the separation of 2 µg
of sweet potato extract.
It is clear from the results obtained that the addition of 2,2,3,3,4,4,4-heptafluoro-l-butanol, post-column,
as an ionizing enhancer when using an electrospray interface, can increase the overall sensitivity of the
tandem instrument to carotenoids by about two orders of magnitude.
Figure 9.37
Positive Ion Electrospray LC/MS Analysis of an
Extract of Heat Processed Canned Sweet Potatoes
Reprinted with permission from R. B. van Breeman, Anal. Chem.,
67(13)(1995)2004., Copyright 1995 American Chemical Society.
The use of sodium replacement ions can also be used to help identify the charged state of the molecular
ion. This possibility was investigated by Neubauer and Anderegg [31] to determine the charged states
of peptide
