Hi all,
I don't know if anyone of you have ever observed the helpful message "Lock anomaly during acquisition" when running 1D protons on a Bruker system?
Our is a Bruker Avance III 400 with an L-TRX lock system. This happens somewhere in the region of 1 in 25-100 samples, and it doesn't seem to be restricted to a particular solvent. Because it happens so rarely I've only seen it happen in when running in automation, so I haven't been able to catch it and try out some of the BSMS Service Web diagnostics (the self-test runs fine). Most of the time the "lock anomaly" error to appear for the proton spectra, but not for any subsequent experiments. On occasion the proton will run just fine, but then the following COSY and/or HSQC experiments will also give the "lock anomaly" error, although for those there is no apparent effect on the spectra, and it is not immediately obvious if any of the increments have been affected by the lock issues.
Sometimes the proton spectrum will just be noise, presumably because the lock has effectively moved the offset into the wrong place, but most of the time for e.g. a 16 scan spectrum you'll see 16 separate peaks for TMS. I've also seen it give e.g. 1 big peak from 5 co-added scans, and 11 smaller peaks, so for whatever reason the lock can also start malfunctioning midway through acquisition. On occasion these symptoms even happen without the benefit of the lock anomaly error.
Any ideas?
Thanks!
Geoff
Dr. Geoffrey Akien
g.akien_at_lancaster.ac.uk
NMR Technician
Department of Chemistry
C07 (office) and A073/4/5/6 (lab), Faraday Building
Lancaster University
LA1 4YB
Office: 01524 593790
Received on Thu Oct 29 2015 - 23:41:33 MST