Figure 2. Elution profile of 1 from a 10 1 mm i.d. GP resin SPE
cartridge with methanol-d4 and after direct injection of the compound
dissolved in 6 íL of methanol-d4 into CapNMR probe, obtained by
determination of signal-to-noise ratios in 1H NMR spectra recorded
for each 1-íL increment of the eluting solvent/push solvent volume
(signal region ä 0.50-1.50, noise region ä 6.50-8.50). The SPE
elution profile was corrected for the dead volume of the cartridge and
the clamp (10 íL).