Structure elucidation of unknown pollutants in environmental samples by coupling of HPLC to NMR and MS
HPLC coupled simultaneously to NMR and MS is particularly suited to the identification of unknown polar, non-volatile compounds in complex environmental samples, i.e. to non-target analysis of such samples, if pollutants are present in the ppb range. Both methods give complementary structural information. Optimum information on unknowns is gained if both techniques are coupled on-line. This review discusses the fundamental aspects of on.line HPLC-NMR, HPLC-MS and HPLC-NMR-MS and compares the advantages and disadvantages of these methods for target and non-target analysis with emphasis on their potential for the structure elucidation of unknowns. The application of these hyphenated techniques to environmental samples is illustrated with contaminated ground water from a former ammunition plant, leachate from industrial waste disposal sites, waste water from a textile company and soil polluted with polycyclic aromatic hydrocarbons as examples.