Superheated heavy water as the eluent for HPLC-NMR and HPLC-NMR-MS of model drugs

Superheated heavy water can be used as the eluent for reversed-phase chroma tography with on-line HPLC-NMR and HPLC-NMR-MS detection. The method has be en demonstrated for the separation of model drugs (analgesics and caffeine) on a poly(styrene - divinylbenzene) stationary phase in isothermal and tem perature-programmed modes. One- and two-dimensional spectra could be obtain ed with less interference from the mobile phase than with conventional HPLC -NMR eluents. Unlike supercritical fluid chromatography-NMR, the spectra co uld be measured at room temperature and atmospheric pressure. The combinati on of superheated water HPLC-NMR-MS chromatography enables both NMR and MS spectra to be obtained simultaneously for the same sample.