请教：H－NMR

wuningshi

对油品而言，核磁共振测的是什么？

celan

以下是引用wuningshi在2007-12-6 15:12:35的发言：

对油品而言，核磁共振测的是什么？

可以测定成分的类型，比例。。。

celan

Quantitative analysis of complex mixtures by NMR is often hampered by heavily overlapping signals
in 1D 1H or 13C spectra. To resolve the overlap problem, we have been looking at the possibilities of
using heteronuclear correlated 2D NMR methods for quantification. In this work, we applied 2D INEPT to
analyze mixtures of tetradecane and squalane, which represent typical substructures of lube oil fractions.
The factors affecting correlation peak volumes, namely the polarization transfer delays within pulse
sequence, multiplicity of CHn group and the magnitude of 1J.C,H/ couplings were taken into account by
product operator formalism calculations. The results indicate that if absolute precision in quantification is
not essential, the current approach can be used for the quantitative analysis of the molecular composition
of complex mixtures when conventional 1D NMR methods fail.

celan

INTRODUCTION
As one of the most commonly applied structural elucidation
methods for organic compounds, NMR spectroscopy
is an excellent tool for studying hydrocarbon-based oil
products. The average molecular composition of the mixture
can be readily estimated from structural parameters
gained from one-dimensional (1D) NMR measurements.
The structural parameters, e.g. aromatic, olefin,
paraffin and naphthene contents, characterize conventional
lube oils fairly well, and help to predict product properties.
However, the exact molecular characterization of
these mixtures is not so straightforward as with pure
compounds.