Fig. 6: IRIS spectrum of the m/z 159 MS2 ion from [citrulline + H]+. | Communications Chemistry

Fig. 6: IRIS spectrum of the m/z 159 MS2 ion from [citrulline + H]+.

From: A spectroscopic test suggests that fragment ion structure annotations in MS/MS libraries are frequently incorrect

Fig. 6

The measured spectrum is shown as the black trace in a–c. The spectrum predicted for the annotation in mzCloud deviates substantially from the measured spectrum (a). The non-cyclized isomer provides a reasonable match for most bands observed experimentally (b). To account for the experimental intensity near 1550–1700 cm−1 and at 3600 cm−1, a minor contribution of the 7-membered ring structure is invoked (c). Proposed reaction mechanisms leading to these fragment structures (d).

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