| Nuclear Magnetic Resonance?NMR?technology has been extensively applied in fundamental scientific research,medical diagnosis,manufacturing quality control and analysis,and other fields,with its advantages of convenient,straightforward and non-destructive to samples.However,in some case of complex samples,the NMR signals are overlapped and interacting with each other,therefore it leads to more complicated while less efficient data analysis,due to similar compositions and close structures of major components in the samples.In this paper,various novel methods of NMR,including nuclear spin singlet preparation and filtering technology,as well as NMR fingerprint technology,are explored to solve some practical problems in different applications of NMR.Application and manipulation of proton nuclear spin singlet states are studied for specifically observation of biomolecules in a complicated sample system.In our first project,three different nuclear spin singlet preparation sequences,including SLIC,M2S and optimal control pulses are used,using one of the two-spin system in tripeptide AGG as example,and their efficiency are compared and mechanisms behind this are discussed.Then we use SLIC pulse to further study the efficiency of observation for a three-spin system in dopamine molecule either for samples at different concentrations,or more complicated samples with other biomolecules.In the case of edible oils,which are composed of fatty acids with similar components and properties.We develop a magnetic resonance fingerprint spectroscopic with a set of new pulse sequence.With this method,NMR relaxation differences among different edible oils are amplified.Their T2 distribution fingerprint regions and T1-T2correlation fingerprint regions have been used for identification of different oil samples.It has been demonstrated that this method is efficient in identification of oil samples of different types,or samples adulterated with either water,fried oil,lard or butter. |
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