Solid State NMR Capabilities

MRI Imaging

MRI is one of the most recent and exciting developments in NMR and is a logical extension of the basic principles of magnetic resonance. The MR scanner provides a non-invasive method of imaging sensitive to subtle differences in water distribution, structural integrity, local flow and other measurements. Intertek laboratories offer expertise in MRI/NMR, including multi-slice, multi-echo and 3D resconctruction capabilities. Materials characterisation applications include a range of polymeric materials such as plastics, rubbers and composites. Formulations applications include solid dosage form pharmaceuticals such as pills and tablets, and semi solids such as gels and pastes.

NMR MRI principles: According to the Larmor relationship, protons in a strong magnetic field precess faster than those in a weak field. If the magnetic field across an object, e.g. two H2O capillaries, is varied by means of a field gradient applied on top of the main magnetic field, The resonant frequency of the protons in the two sites will be different. Instead of a single NMR peak, two peaks are produced and the image is spatially localised. Application of gradients in orthogonal directions can lead to the reconstruction of 2-D and 3D images using 2-D FT techniques. If the applied field gradient is linear, the frequency spectrum obtained after FT becomes a 1-D profile of proton (water) concentration versus distance in the chosen direction. This is known as 1-D mapping. Intertek NMR MRI expertise includes: 3D Reconstruction Multi-echo Multi-slice

Solid-state NMR:
The solid state NMR service utilises a Bruker DSX 300MHz spectrometer equipped with a micro imaging accessory. The instrument is equipped with various probes for a range of applications:

• 4mm CPMAS probe – Rotation speed up to 12KHz
• 7mm MAS probe – Rotation speed up to 6KHz
• 7mm CRAMPS probe
• X-Diffusion probe
• High power wide line probe
• 1000 Gauss cm-1 diffusion probe
• Micro imaging probe – inserts up to 25mm diameter
• Stray field imaging (STRAFI)

• MRI & Relaxometry
• Pharmaceutical Industry – tablet swelling / cracking /dissolution /drying, diffusion of benefit agents, etc.
• Polymorph studies of APIs both in a raw material and tableted form, gives supporting evidence to XRD analysis. Solid-state 13C CPMAS NMR is utilised to study crystalline polymorphs and the amount of crystalline and amorphous phases of carrier species in pharmaceuticals. Analysis of 13C spectra allows us to obtain data on inert carrier species - drug interactions and also simple polymorph differentiation/identification and amorphous material content
• Agriculture – Seed germination, plant growth under various conditions, cooking processes, fruit traumas, etc.
• General – Kinetics of drying / wetting, diffusion, pore filling, soap bar mushing, ingress and egress of water, oil in porous rocks.
• Solid-liquid ratios of oils and fats – e.g. The margarine industry
• Quantitative determination of phase composition, e.g. solid, liquid crystal, isotropic of soap bars, detergent products
• Plasticisation of polymers.
• Glass transition temperatures of polymers.
• Whereabouts of fluoride species in toothpastes