Theme 1 colloquium: "NMR-based chemosensing via para-hydrogen hyperpolarization: application to the quantitative analysis of complex mixtures" (Lecture)
- Tuesday 6 November 2018Add to my calendar
- from 16:00
dr. Marco Tessari (Biophysical Chemistry)
Nuclear Magnetic Resonance spectroscopy is widely used for identification and quantification of analytes in solution. However, when dealing with complex mixtures such as biofluids or natural extracts, several issues arise that can seriously hamper NMR chemical analysis. In the first place, NMR detection of dilute components (i.e., at low micromolar concentration) is impeded by the low sensitivity of the technique. An additional hurdle is represented by NMR signal overlap: in solutions containing hundreds of components at concentrations ranging from submicromolar to high millimolar, the modest 1H resonances dispersion (typically ∼10 ppm, a few kHz) determines a formidable signal crowding. This represents a serious obstacle to the quantitative determination of any analyte, except for the most concentrated ones. I will present an approach based on the reversible association of specific analytes to an iridium complex which acts as a selecting receptor. This NMR chemosensor allows the selective detection of target compounds while removing the large background originating from the complex matrix. Importantly, this association can also be exploited to generate highly enhanced NMR signals via parahydrogen (p- H2) induced nuclear spin hyperpolarization. We have recently applied this technique to biofluids and natural extracts, in which hundreds SABRE substrates could be simultaneously detected, at concentrations 1000 times lower than by conventional NMR.
dr. Joost Bakker