Application of immobilized free radicals in supercritical fluid chromatography hyphenated with proton nuclear magnetic resonance spectroscopy

Quantitative1H NMR: Development and Potential of a Method for Natural Products Analysis

“…Fischer et al 160 proposed the hyphenation of supercritical fluid chromatography (SFC) with qHNMR. Due to the lack of disturbing proton signals, supercritical CO 2 is an excellent solvent for 1 H NMR spectroscopy.…”

Supercritical Fluid and Unified Chromatography

“…We mentioned several NMR applications earlier (Mobile Phases and (Achiral) Stationary Phases section) in our discussion of superheated D 2 O. Albert included SFC/NMR in a review of NMR coupled to chromatographic separation methods (64). Fischer et al overcame one limitation of SFC/NMR: long spin-lattice relaxation time (65). They synthesized and immobilized free radicals within the interface to reduce these relaxation times.…”

Water soluble, chiral, verdazyl radicals derived from aldoses

“…In addition to the identification of radicals in a diamagnetic background by EPR, radicals can be spatially located through ESR imaging, 1-2 and can be indirectly detected through their ability as efficient fluorescence quenchers. [3][4][5][6][7][8][9][10][11] and through NMR spin relaxation techniques [12][13][14][15][16] In particular, the return of fluorescence combined with loss of an ESR signal when a free radical is destroyed is a powerful method for the detection of various species; recent examples include urushiols, 17 ascorbic acid [18][19][20] and nicotine. 21 Attachment of radicals to a dendrimer core has been recently used to provide a novel, gadolinium free MRI contrast agent.…”