Compositional Analysis via Magnetic Resonance Relaxation Correlation with a Desktop Permanent Magnet

点击翻译按钮获取中文摘要

This RTI grant supports the purchase of a desktop magnetic resonance (MR) instrument for usage with a new MR relaxation correlation measurement, developed by the applicants, that permits facile compositional analysis of solid and semi-solid materials. The instrument is based on a low-field permanent magnet while the measurement relies on the determination of 1H MR signal lifetimes. This system will be a platform for continued development of the new methodology, T1-T2* and T1rho-T2* relaxation correlation, and will permit the earliest and most advantageous application to five research areas of contemporary interest.    Traditional time domain MR signal lifetime measurements excel for liquid analysis but fail when confronted with solids and solid-like mixtures. Time domain instruments require minimal or no sample preparation and are `whole sample' measurements due to facile RF electromagnetic penetration in non-metallic samples. Conventional methods for solid mixture analysis are either surface limited, for example near-infrared, or they are substantially limited to crystalline materials, for example powder x-ray diffraction (PXRD). Our new relaxation correlation methodologies dramatically expand the range of samples and processes which will be probed by this economical low-field time domain instrument.    MR signal lifetimes are very sensitive to molecular dynamics and environment. The new method permits observation and discrimination of a wide range of solid-like species and will discriminate between crystalline and amorphous species (unlike PXRD) in addition to measuring mobile small molecules, for example water or oil, in mixtures of solids. This new instrument, coupled with our methodology, will be employed to analyze five initial classes of solid mixtures/materials. (1) Solid state chemical reactions where solid species are co-mixed as reagents leading to solid products. (2) Composition of solid mixtures of industrial importance. Verification of solid mixing, quality control of commodity chemicals, including phase of natural biopolymers and determination of small molecule content (such as hydrates) are all practical analytical problems in industry. (3) Shale composition, specifically the water and oil content. Direct observation of kerogen signal will permit grading shale maturity. Shale is the source rock for traditional petroleum reservoirs and exploitation of shale resources has revolutionized the petroleum industry. (4) Water, oil and plant fibre mass content in wood materials, and high-value plants like cannabis. Liquids in the plant fibre matrix are straight forward to identify via 1H MR signal lifetime. Observation of the 1H solid plant fibre signal, with appropriate conversion to mass via an average molecular weight, will permit direct determination of component mass percentage without weighing. (5) Battery Studies. MR signal lifetime analyses will permit characterization of electrolyte decomposition during battery operation.