By Ben Reiner
Functional polymers are a key feature of complex formulations across a wide class of material science disciplines. However, the presence of small molecule or oligomeric impurities can often convolute spectral analysis. Nuclear magnetic resonance (NMR) spectroscopy is an incredibly information-rich technique which is well poised for analysis of complex mixtures. Polymer and small molecule resonances can often be distinguished by line shape alone in cases where sufficient spectral resolution is present. When spectral resolution is inadequate or not accessible owing to experimental time or budget, techniques which can modulate select signals are of particular interest. Here is presented how tailored non-uniform sampling schedules can selectively enhance small molecule signals in multidimensional spectra in a controlled programmatic fashion. The focus will be on the practical value for real structural characterization campaigns in contrast to alternative conventional strategies. Additionally, the proportional effect of non-uniform sampling schedules over complex formulations will be compared to simple formulations only containing small molecule targets.