Abstract: Solvent signal suppression is essential for biological NMR spectroscopy. For applications using reversed-phase HPLC-NMR or studies of natural product extracts with mixed solvents, simultaneous suppression of the signals from multiple solvents is often required in order to get high quality NMR spectrum. There are a number of approaches developed for solvent signal suppression. Although most of these approaches can be used for multiple solvent signals suppression, simple methods with high suppression efficiency are still needed. In this article, double WATERGATE approach was extended for such purpose. Two simple extensions, DSSW5 (Double Solvent Suppression WATERGATE) and GASP-W5 (GASP-based WATERGATE), were established and used to acquire one- and two-dimensional (1D & 2D) NMR spectra in HPLC-NMR and from natural product extracts, respectively. The results demonstrated that the new methods are easy to implement and applicable for routine NMR spectroscopy.

Key words: NMR, solvent signal suppression, WATERGATE, HPLC-NMR, natural product analysis