-Techniques-

Nuclear Magnetic Resonance (NMR) Spectroscopy

Nuclear Magnetic Resonance (NMR) spectroscopy is an analytical technique used to determine the chemical molecular structure of a compound. NMR Testing provides both quantitative and qualitative data on the composition of a sample. Nuclear Magnetic Resonance spectroscopy can be used for quality control, for research, to identify an unknown, or to determine the content and purity of a sample.

A simplified description of NMR Analysis is that the sample, usually dissolved in a liquid, is placed into the instrument, which contains a magnetic field. A radio frequency pulse is then sent through the sample solution in order to orient the magnetic moments of the nuclei in the solution. As the magnetic moments relax, they exhibit a free induction decay. The free induction decay is Fourier transformed into an NMR spectrum. The NMR spectrum displays chemical shifts for the individual nuclei; and from these chemical shifts, the chemical molecular structures of the compound can be determined.

Capabilities

Element Midland currently has a Varian 400MHz NMR System spectrometer, equipped with a broadband Pulse-Field Gradient (PFG) probe for the analysis of low frequency X nuclei (15N – 31P).

Typical NMR analyses include:

Proton and Carbon-13
Silicon-29 and Fluorine-19

NMR Testing is capable of analyzing a wide range of nuclei. Notables include phosphorus, boron, carbon, silicon, and nitrogen. Some Applications for liquid NMR Analysis includes the following (there are some limitations in terms of sample types, most organics are suitable):

Identity confirmation.
Purity Assay.
Identification of unknowns.
Structure elucidation.
Emulsion droplet size measurement.
Measurement of diffusion coefficients.

Available Types of Sequences:

1D with the option of pre-saturation to suppress strong signals.
2D Homonuclear correlations.

Nuclear Magnetic Resonance spectroscopy also has variable temperature (-25 to 130 C) capabilities, suitable for analyzing polymers and other materials at high temperatures or monitoring chemical reactions at low temperatures. Advanced one and two-dimensional experiments are available and necessary tools for the deconvolution of complex mixtures and materials, especially for pharmaceutical characterization.

These include: