Figure 3.
Evaluation of the proposed “Add to Subtract” approach on sample set 2. (a) Pre-sat spectrum of the protein-precipitated human blood serum; (b) Spectrum after removing the glucose background by “Add to Subtract”; (c) Spectrum after removing the glucose background by subtraction of the spectrum of a pure glucose solution; (d) Spectrum after removing the glucose background by semi-automatic curve-fitting using Chenomx NMR 5.1 professional; (e) CPMG spectrum of an intact serum sample without protein preciptation; (f)–(h): results of background subtraction, as in (b)–(d), but applied to the spectrum in (e); (i): a magnified view of (b) with peak assignments. Subtraction using Chenomx NMR Suite 7.1 evaluation resulted in spectra similar to (d) and (h), but with higher residual glucose signals.