truncated m/z in mummichog files

March 31, 2016, 02:33:45 PM

Hi,
I am using XCMS online and I noticed that in my downloaded files in the mummichog folder, tsv folder file _tentative_featurematch_mummichog the m/z values are truncated to 4 decimal places. However, when I export the results table from xcms online the mzmed contains 7 decimal places. Therefore, some m/z identities in mummichog correspond to several features in the results table file due to the fact that the mummichog file has truncated m/z. How can I get all 7 decimal places from mummichog?
Thanks

Re: truncated m/z in mummichog files

Reply #1 – May 04, 2016, 12:53:31 PM

Is the data you collected really accurate to 7 decimal places for m/z? I believe 4 is the current standard for the highest resolution instruments (someone correct me if I'm wrong). Everything in mummichog's main reference database, metafish network, is set at 4 decimal places for m/z as well.