Applying benchtop NMR spectroscopy in the pharma lab
About the blogger: John Paul Cerroti is director of sales, EMEA, at Magritek GmbH, a nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) solutions provider. Cerroti has worked in analytical instrumentation for nearly thirty years. With a background in materials science, he has held senior sales and marketing roles for many of the leading innovators in spectroscopy tools, including PerkinElmer, Renishaw and Oxford Instruments.
The latest analytical technology to move to the benchtop is nuclear magnetic resonance (NMR) spectroscopy. High-end, high-cost instrumentation has dominated the NMR sector for many years, with both the initial purchase price and annual running costs putting the technique beyond the reach of almost all individual laboratories. Specialist is the word that would come to mind. A special room with special supplies and, not least, a specialist to run and interpret the data produced.
This might be compared with how mass spectrometry was twenty years ago, but look where it is today — buyers have a choice of many benchtop footprint instruments from multiple suppliers. The last twelve months has seen the world of NMR make similar strides, with the arrival of several new instruments and suppliers.
The world of organic chemistry is the principal beneficiary from the advent of benchtop NMR spectrometers. Whether the user is in academia or in research, in the chemical or pharmaceutical industry, a key goal of any synthetic chemist is to be able to quickly and reliably identify exactly what has been made at each stage of the process. NMR is the ultimate technique for this. While mass spectrometry, infrared (IR) and ultraviolet (UV) spectroscopies are widely used, organic chemists agree that NMR provides the most definitive information about the structure of an organic compound.
In academia, benchtop NMR is now being used for both teaching and research at institutes including the group of Professor Magid Abou-Gharbia at the Temple University School of Pharmacy and in the NMR labs of Professor Joseph Hornak at the Rochester Institute of Technology.
For organic chemists, proton (1H) and carbon-13 (13C) NMR form the backbone of routine molecular analysis. For the first time, 1D and 2D proton-carbon NMR is available in a benchtop instrument — Magritek’s Spinsolve Carbon spectrometer — that meets the needs of synthetic chemists, academics focused on organic chemistry education, pharmaceutical and medicinal chemists and researchers working on the structure elucidation of organic molecules, without the use of cryogens or special facilities.
Users of benchtop systems have found them to be particularly convenient and robust to use. Ease of operation makes them perfect for bench chemists and analysts who need immediate results. To get answers in the lab in a couple of minutes beats sending samples away for analysis.
A long-held aspiration of synthetic chemists and chemical engineers is an NMR instrument that can both monitor reactions and be deployed to synthetic laboratories and pilot plants. Now it is possible to bring the NMR to the synthesis instead of having to bring the synthesis to the NMR. The key ability to monitor reactions by tracking reactants, products, intermediates and by-products and to determine end-points is now available. Such work has recently been reported at the BAM Institute in Berlin where the process analytical technology group works on the development and validation of analytical online and at-line methods.
A simple acetalisation reaction above, using a flow cell passing through the spectrometer, illustrates this reaction monitoring capability.
In the photo, the software has been configured to take a 1D proton NMR spectrum every 30 seconds, and the reaction is followed for just over one hour. This application takes advantage of the inherently quantitative nature of NMR, enabling chemists to follow the reaction as it is occurring, without the need for chemometrics or other complex analysis methods that are so often necessary when monitoring reactions using other analytical techniques.
In conclusion, it has been demonstrated that benchtop NMR is suited to both teaching and use in an industrial laboratory environment. It will continue to grow as a technique, creating new opportunities for timely and cost-effective analysis.