Please, cite this online document as:
Vasini E.M., Sykora S., Cobas C.
PcBc - Novel Automatic Phase & Baseline Correction Algorithm,
Poster at 6th PANIC, La Jolla (CA), March 3-8, 2018,
Manually, phase (PC) and baseline (BC) corrections in 1D NMR spectra were always done sequentially one after another. In addition, the Bc was always done only on the "real" part of the spectrum and not on the imaginary part. However, one often notices that there is a mutual interference between the two corrections, causing uncertainty about the best correction in the vicinity of an acceptable solution. In addition, the fact that baseline correction is not done on the imaginary part implies that when one tries to iterate the whole process, any change in phase parameters brings back into the displayed real part the uncorrected baseline artifacts present in the imaginary part. Consequently, though a lot of work on the two (separate) corrections has been done over the years, further investigation is still called for.
The problem becomes particularly imperative when one needs a fully automatic and very robust algorithm to apply in industrial applications of NMR spectroscopy, particularly those characterized by a very high sample throughput and/or a continuous or pseudo-continuous sampling characteristic, for example, of a process-control setup.
Here we present a new iterative algorithm in which the 'quality function' is based on the amplitude histograms (real and imaginary) of the spectrum and of its numerical first derivative and anti-derivative. Apart from some convenient features of histograms, the fully automatic algorithm handles BOTH corrections simultaneously (PcBc rather than Pc + Bc), and it applies the baseline correction to BOTH the real and the imaginary parts of the spectrum.