Application of 31P NMR

McLaughlin AC, Cullis PR, Hemminga MA, Hoult DI, Radda GK, Ritchie GA, Seeley PJ, Richards RE (1975) Application of 31P NMR to model and biological membrane systems. FEBS Lett 57 213-218... 

Phosphorus -31. NMR spectroscopy using 31P, the ordinary isotope of phosphorus, also has many uses.466 Application of 31P NMR to living tissues has been extraordinarily informative467 and is dealt with in Chapter 6. The many phosphorus nuclei in nucleotides, coenzymes, and phosphorylated metabolites and proteins are all suitable objects of investigation by NMR techniques. 

An interesting application of 31P-NMR is the study of the transmembrane transport of drugs. 

Abstract In this chapter, progress in methodology and new applications of 31P NMR... 

It is of interest to examine the development of the analytical toolbox for rubber deformulation over the last two decades and the role of emerging technologies (Table 2.9). Bayer technology (1981) for the qualitative and quantitative analysis of rubbers and elastomers consisted of a multitechnique approach comprising extraction (Soxhlet, DIN 53 553), wet chemistry (colour reactions, photometry), electrochemistry (polarography, conductometry), various forms of chromatography (PC, GC, off-line PyGC, TLC), spectroscopy (UV, IR, off-line PylR), and microscopy (OM, SEM, TEM, fluorescence) [10]. Reported applications concerned the identification of plasticisers, fatty acids, stabilisers, antioxidants, vulcanisation accelerators, free/total/bound sulfur, minerals and CB. Monsanto (1983) used direct-probe MS for in situ quantitative analysis of additives and rubber and made use of 31P NMR [69]. 

Heteronuclear correlation (HETCOR) spectroscopy is a standard two-dimensional NMR technique. The resolution of 31P 1H CPMAS spectra is generally not sufficient to unequivocally detect the HP042 ions and the apatitic OH- ions in bone or dentin samples.15 In this regard, the breakthrough came from the first application of 31P 1H HETCOR to HAp and bone samples,24 where the correlation peak at 0.2 and 3 ppm of the 1H and 31P dimensions, respectively, has been established as the spectral marker of apatitic OH- ions. To enhance the spectral resolution in the XH dimension, 1H homonuclear decoupling was employed during the fi... 

D MAS NMR techniques In the previous section, we reported applications of ID NMR spectroscopy, which enables the determination and quantitative characterisation of different phosphorus groups Q" via deconvolution of 31P resonances. Unfortunately, such an approach has at least two limitations. First, the 31P MAS NMR spectra suffer from broad and overlapping signals, and these methods fail when more complicated systems are to be analysed. Second, the structural information is significantly limited, for example the connectivities of Q group or through-space interactions cannot be established from only ID spectra. To overcome these limitations, it is necessary to apply more advanced 2D NMR techniques. 

Like H and 13C, the 31P nucleus has a spin of Vi. It is also the only stable isotope of phosphorus. Furthermore, the 31P chemical shift is highly sensitive to chemical structure and its chemical shift range is broad. As a consequence of these features, 31P NMR spectroscopy has had broad applications in the study of complexes of phosphines and other phosphorus-containing ligands. A recent review provides a variety of examples, including spectral analyses, of applications of 31P and 13C NMR to transition metal complexes with phosphorus-containing ligands.44... 

A very similar application of the modified Bloch equations was based in the work of Adams and Connelly.4 ESR spectra (Figure 5.8) of [Mo P(0 Me)3 2(MeC = CMc)Cp] show the expected triplet (two equivalent 31P nuclei) at 280 K, but only a doublet at 160 K. At intermediate temperatures, the lines broaden. The interpretation is that the alkyne undergoes a pendulum oscillation, which in the extrema diverts spin density from one or the other phosphite. Interestingly, the diamagnetic cation undergoes a similar motion on the NMR time scale, but then the alkyne undergoes a complete rotation. Thus, analysis of the effect leads to a measure of the rate of the oscillation. The... 

Because the application of NMR spectroscopy to environmental samples is relatively new, we focused our studies on the identification and characterization of DOP by 31P FT-NMR spectroscopy. Ultrafiltration and reverse osmosis concentration techniques were employed to increase the dissolved organic phosphorus concentrations to the detection level of 31P FT-NMR techniques (approximately 10-20 mg of P/L). With these concentration methods a DOP concentration factor of up to 2000 is obtainable. This chapter reports the use of 31P FT-NMR spectroscopy in the analysis of DOP. In... 

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