A pH-enhanced resolution in benchtop NMR spectroscopy.

Area of Science:

• Analytical Chemistry
• Spectroscopy

Background:

• Nuclear Magnetic Resonance (NMR) spectroscopy is a powerful analytical technique.
• NMR titration experiments are crucial for determining molecular binding affinities and concentration-dependent effects.
• Traditional NMR titrations involve lengthy series of measurements.

Purpose of the Study:

• To adapt a recent concentration gradient NMR approach for cost-efficient benchtop NMR spectrometers.
• To overcome the limitations of the original chemical shift imaging (CSI) method, which requires high-resolution instruments.
• To provide a more accessible method for studying concentration-dependent phenomena using NMR.

Main Methods:

• A novel method utilizing a vertical tube shifting device was employed instead of CSI.
• This device allows measurement of spectra from different sample volumes along a concentration gradient within the NMR tube.
• The approach was validated using test samples (L-tyrosine, 2,6-lutidine) and real-world samples (infant formula, energy drink).

Main Results:

• The modified method successfully adapted the concentration gradient approach to benchtop NMR machines.
• The technique demonstrated improved spectral resolution compared to the original CSI-based method.
• Broader sampling of pH values was achieved, enhancing the utility of the experiment.

Conclusions:

• The proposed vertical tube shifting method offers a practical and cost-effective alternative for NMR titration experiments on benchtop spectrometers.
• This adaptation democratizes the study of concentration-dependent effects using NMR.
• The method shows significant potential for applications in analytical chemistry, including food industry analysis.