Hi everyone, What range of mass error do natural product journals generally accept. Is a 31 ppm mass error run in a Bruker q-TOF MS acceptable for natural products journal?
The journals scope of natural products does not accept errors greater than 6 ppm. But it is only required the error indication in the new compounds. Often elemental analysis replaces the mass data of high resolution. Sorry but 31 ppm mass error is excessive.
Does the mass error tend to change with multiple runs? If so how much ppm can it change?I mean to say if I do multiple injections can I get results that may have less mass error than this. I have no doubts on the molecular formula of the molecule. Could this large mass error be a result of false internal calibration before the use of the instrument?
If you are sure of the compound formula, you may try to purify the compound, analyzes it in different conditions such as: switch to positive / negative mode or increase/ decrease the cone energy. Of course I'm from the principle that it is calibrated correctly.
Thank you Ana. I will try the cone energy. The molecular ion peak shows up in negative ionization mode only cause it has two ester linkages in it. As the compound was isolated using prep TLC plates (gave very good spectra in NMR), I think I can purify it more running a HPLC and do a HRMS again. Hope it works.
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