InNMR: Direct In Situ Studies of Transport Phenomena Enabled by an Innovative NMR-Tube Insert

A novel discoid insert that can be positioned into a standard NMR tube using an associated plunger tool has been developed. By attaching any type of semipermeable barrier to the bottom of the insert, the detection volume of the tube can be divided into two or more chambers, separated by a barrier of choice. Slice-selective experiments are then utilized to study a plethora of transport phenomena in real time by NMR spectroscopy. The technological device is presented together with a proof of concept for three different applications: permeability studies, diffusion-controlled pH titrations, and diffusion-controlled protein titrations. The developed approach unlocks new tools for scientists working in the fields of drug discovery, organic chemistry, biochemistry, chemical biology, microbiology, or electrochemistry that will enable new types of experiments to be performed by NMR spectroscopy.