Dr Catherine Santai is an Associate Professor of Chemistry & Biochemistry and Program Lead of the Integrative Sciences program at Harrisburg University of Science & Technology. The program utilizes a number of analytical techniques teaching undergraduates about their use, giving them the experience ahead of entering research or industrial roles in later life. So far, the Magritek 60 MHz Spinsolve Benchtop NMR Spectrometer has been used in the Organic Chemistry and Biochemistry laboratory sessions. These provide invaluable hands-on lessons about NMR techniques and analysis of a variety of compounds. NMR is used alongside FTIR (Fourier transfer infrared), AAS (atomic absorption), UV-VIS (ultraviolet – visible) and fluorescence spectroscopies.
The Attached Proton Test (APT) is a very useful experiment that, like DEPT, provides information about how many hydrogens or protons are attached to a particular carbon atom. Both DEPT and APT do this by “editing” the spectrum so that the carbon signals point either up or down depending on the number of attached hydrogens. APT differs from DEPT in several significant ways, though. The first is that quaternary carbons (i.e. carbons that bear no hydrogens) are retained in the APT spectrum, whereas they are absent in DEPT (though there are variants of the traditional DEPT experiment that do retain the quaternary signals). In APT, quaternary and methylene carbons point down by convention, while methyl and methine carbons point up. Figure 1 shows a comparison of a conventional carbon, APT and DEPT-135 spectra of a sample of propyl benzoate.
Fatty acids consist of long carbon chains ending with a carboxylic acid on one side and a methyl group on the other. Most naturally occurring fatty acids have an even number of carbon atoms and can be either saturated or unsaturated. Unsaturated fatty acids have one or more double bonds between carbon atoms. Typical fatty acids found in vegetable oils are saturated palmitic acid (C16:0) and stearic acid (C18:0), as well as oleic acid (C18:1) with a single double bond starting at carbon nine (omega-9), linoleic acid (C18:2) with two double bonds starting at position 6 (omega-6), and alpha-linolenic acid with three double bonds starting at position 3 (omega-3). (more…)
The group of Professor Yoshida at the Department of Synthetic Chemistry and Biological Chemistry of Kyoto University has recently published an article showing how Spinsolve benchtop NMR spectroscopy can be used to optimise the reactions of aminating reagents to achieve an efficient C–N bond formation without using any catalyst.
The permitted hydrocarbon content of discharged water from offshore oil and gas exploration is becoming increasingly limited by more stringent legislation. This creates the demand for measurement methods that are sensitive enough to detect contaminants at ppm level, but also compact and robust to field conditions. The group of Professor Mike Johns at the University of Western Australia in Perth has developed a benchtop NMR method to quantify the hydrocarbon content in water at the ppm level.
Assigning peaks in the NMR spectrum is a fundamental part of structure verification. Depending on a variety of factors including the size and complexity of the molecule, and the field strength the NMR data are collected at, this can be a straightforward exercise or an extremely challenging one! For example, in the case of a fairly simple compound like lidocaine, it is relatively easy to assign all of the peaks directly in the 1H spectrum using a 43 MHz benchtop NMR spectrometer. However, as a compound’s molecular weight increases so the spectra tend to become more complex, with more resonances and, inevitably, more signal overlap. Assigning the peaks thus becomes significantly more challenging, which is where collecting 2D NMR spectra can help with completing the assignments.
Wageningen University & Research (WUR) is formed from the collaboration between Wageningen University and the Wageningen Research foundation. With the mission “to explore the potential of nature to improve the quality of life,” its staff and students work in the domain of healthy foods and living environments. Dr Teris van Beek is a Lecturer in the Department of Agrotechnology & Food Sciences. Among his responsibilities is the coordination of the undergraduate course in analytical chemistry where 220 molecular life sciences and biotechnology students are introduced to practical spectroscopy each year (UV, IR, MS, NMR, structure elucidation).
At the Achema conference this week in Frankfurt we have a joint booth with Corning Advanced Flow Reactors. We are running a live Spinsolve Benchtop NMR reaction monitoring setup in combination with a Corning Advanced Flow Reactor. If you are Achema, please come and visit us at our joint booth with Corning AFR Hall 9.2 / Booth A32 and see the powerful combination of Corning Flow Reactors and Magritek Benchtop NMR.
Due to their high retail value, some edible oils are often blended wilfully with other more inexpensive vegetable oils. Two recent publications by Kim et al. and Krause et al. in international journals were able to demonstrate that Spinsolve 1H benchtop NMR spectroscopy is a possible cost-effective method for discriminating the authenticity of some vegetable oils.
Overlaid 60 MHz 1H‑NMR spectra of genuine patchouli oils spiked with 9 different adulterants at 20%.