Fig. 6.

Re-referencing of spectral datasets. a and c show an example of an STD SpectrumHit and its best-matched reference before and after applying a re-referencing pipe. b and d illustrate peak shift distributions of experimental STD spectra to their reference spectra before and after a re-referencing pipe was applied. The maximum of the distribution, ~ 0.0075 ppm, (from Fig. 6b), was used to calculate the total adjustment needed to re-reference the STD spectra to their references. d New distribution after the adjustment was applied, with a maximum centred around ~ 0.000 ppm