NMR Workshops

Practical Applications of Water Suppression (PAWS)

Solvent resonances tend to present a challenge to an NMR spectroscopist as they introduce radiation damping artifacts, overflow the analog-to-digital conversion, and significantly attenuate the dynamic range of the receiver, not to mention their tendency to obscure desired resonances of the solute. The use of deuterated solvents is one way to address this issue. However, there are numerous NMR applications where this approach cannot be used for a variety of reasons, such as time & resource considerations, sample integrity concerns, or the need to preserve exchangeable 1H resonances of analyte molecules. Water, of course, is the most common solvent that a spectroscopist would need to suppress. Infamously, an effective concentration of 1H nuclei in water is ~110 M, which could be 8 or more orders of magnitude greater than the solute concentration. Fortunately, significant advances have been made in the field of water suppression in the past few decades, with a dizzying plethora of water suppression schemes and variants thereof available to the practicing spectroscopist, each with their own strengths, weaknesses, and suitability for specific applications.

This IVAN session focused on practical applications of water suppression. We reviewed the basic types of water suppression schemes and their underlying physical principles, important experimental aspects to consider when choosing a suppression scheme for a given application and a type of sample.

The invited panelists each delivered a short presentation that highlights how the application of various water suppression schemes enables their workflows in their respective fields of expertise – namely NMR of nucleic acids with exchangeable protons, detection and identification of trace small molecule process impurities by NMR in biopharmaceutical development and manufacturing, and NMR of complex mixtures such as those encountered in metabolomics and food authenticity investigations. As usual, the floor will be open to all attendees to ask questions and engage in a lively discussion after the presentations.

Hosts: Gennady Khirich & Misha Reibarkh – Merck & Co.

Panelists: Kaitlyn Doolittle Catlin (Genentech), Emmanuel Hatzakis (Ohio State University), & Mihajlo Novakovic (ETH Zurich)



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