Nuclear magnetic resonance (NMR) spectroscopy is one of the most powerful analytical tools used to probe details of molecular structure and dynamics. It requires very high magnetic fields and, hence, generally uses extremely large, powerful magnets. The advent of small, powerful magnets has allowed much less expensive low resolution NMR instrumentation to be designed, making it feasible to measure commercially important characteristics of dispersion behaviour and performance, including the wetted surface area of particulate suspensions and emulsion droplet size. An important additional practical application is the ability to determine competitive adsorption and/or displacement of polymers and surfactants at interfaces. This article presents a brief overview of these new approaches together with an example of each measurement.
1H NMR spectra are usually interpreted by hand, which is very time consuming, and can become a process bottleneck in fields such as high-throughput NMR. Greater automation of the spectral analysis process has become essential if NMR is to be of value as a high-throughput analytical method in the future.
Dirk Lachenmeier, Marina Gary, Yulia Monakhova, Thomas Kuballa and Gerd Mildau describe “Rapid NMR screening of total aldehydes to detect oxidative rancidity in vegetable oils and decorative cosmetics”. Lipid oxidation produces rancid products, which are both unpleasant and potentially toxic. The authors describe the use of NMR to screen food and cosmetic products. Whilst, vegetable oils were generally found to be in good condition, German women may wish to be careful of their lipstick, especially if they have had kept it for a while!
An NMR tour of Mediterranean anise-flavoured alcoholic beverages.
This article outlines the use of the DOSY NMR method applied to drug analysis and screening for counterfeit drugs or fake herbal medicines
A brief history and personal recollection of the development of magnetic resonance imaging (MRI).
There has been much debate about which program can predict NMR spectra the best. It is well known within the NMR community that spectra prediction strongly depends on the “quality” of the starting data sets for those systems which use real data as a knowledge base. It has become a hot topic in some blogs, although disappointingly most of the authors tend to have affiliations to one software vendor or another.
The purpose of this short review article is to highlight some capabilities of qNMR spectroscopic methods in drug quality evaluation, indicating that qNMR spectroscopy should be more often applied when chromatographic methods are not working effectively.
Our focus here is analytical procedures and the role of nuclear magnetic resonance (NMR) in particular. These have, until now, largely relied on conventional chromatography, and vibrational spectroscopy—infrared (IR), Raman and near infrared (NIR) spectroscopy. In spite of inherent difficulties with peak assignment and reliable quantification, vibrational spectroscopy has been used to derive information on reaction progression to impart fundamental understanding. This article sets out a wider scope to show how NMR can play a key role. Furthermore, NMR integrates well with established procedures to provide a suite of useful technologies that make the PAT challenge tractable.
Helen Williams and Mike Claybourn
AstraZeneca, Silk Road Business Park, Macclesfield, Cheshire, SK10 2NA, UK
Raymond J. Abraham and Mehdi Mobli
Chemistry Department, The University of Liverpool, PO Box 147, Liverpool L69 3BX, UK
HD Science Limited, 16 Petworth Avenue, Toton, Nottingham NG9 6JF, UK
Luisa Mannina,a,b Anatoli P. Sobolevb and Annalaura Segreb
aUniversity of Molise, Faculty of Agriculture, 86100 Campobasso, Italy
bInstitute of Chemical Methodologies, CNR, 00016 Monterotondo Staz., Rome, Italy
Technical Director, Oxford Instruments Superconductivity
It is now more than fifty years ago that Felix Bloch and Edward Mills Purcell independently discovered a phenomenon called nuclear magnetic resonance (NMR). Only a few years later, in 1952, both received the Nobel Laureate Physics award for this discovery. Purcell and Bloch were the first to “listen” to the whisperings of hydrogen. They eventually obtained an NMR spectrum representing the different “pitches” of the nuclei, a property, which reflects the physico–chemical (electronic) neighbourhood of the nucleus.
A stage in the ever-increasing magnetic field strengths in NMR spectroscopy.