LC-NMR – Who in Their Right Mind Would Even Consider it?

Bernie Monaghan (BM): Could you tell us a little about the group in which you work in Sunderland?

Nicolas Haroune (NH): Chemispec was established in 2000 when the University obtained a grant from the ERDF (European Research Development Fund) to purchase analytical equipment with the aim of helping small and medium enterprises in the North East of England. 2 NMR spectrometers (500 and 300MHz), 1 mass spectrometer (Apex II FT/MS) were purchased. More particularly, the 500MHz spectrometer was equipped with a flow probe for LC-NMR applications. We have now been offering LC-NMR analysis services nationwide for nearly 10 years to industries in the pharmaceutical and chemical sector. We have now been offering LC-NMR analysis services nationwide for nearly 10 years to industries in the pharmaceutical and chemical sector.

BM: Which manufacturers Instruments do you use currently? Are there any technological reasons for making these choices?

NH: These instruments were purchased from Bruker Ltd, a market leading manufacturer in this area.

BM: Can you give the readers some background into the interest and need for such a technique? What are the practical operating issues that have to be overcome to obtain high quality data?

NH: Our LC-NMR equipment allows the detection of only microgrammes quantities of unknowns. It also allows:

• The detection of all protons containing analytes
• It is a non invasive technique so it is possible to recover the sample after analysis
• It provides detailed structural information which are complementary to mass spectrometry analyses
• It represents a time saving since there is no need to collect fraction and as such the sample preparation minimised

These advantages make the LC-NMR suitable for the analysis of components in complex mixture at low concentrations, where difficult to purify or to unstable for isolation by Silica gel chromatography or preparative HPLC.