Date: 28 April 2021 | Category: News
Here we present our latest application note, Fast Stern-Volmer analysis in flow, prepared by the VilelaLab at Heriot-Watt University. In this work, an E-Series flow chemistry system was set to perform Stern-Volmer analysis in flow. It minimised human errors and improved reproducibility of results.
Stern-Volmer relationship and photoredox chemistry
Stern-Volmer analysis allows study of photochemical intermolecular deactivations. This physical phenomenon is key for a better of understanding photoredox catalysis.
A photoredox catalyst promotes reactions by harnessing the energy of photons and transferring the energy into the reactants. Both catalyst and substrate need to be compatible for a successful energy transfer. Otherwise, the excited catalyst will fluoresce, dissipating that energy. The Stern-Volmer relationship is key to elucidate kinetics of photoredox processes.
Photoredox catalysis has experienced a renaissance with flow chemistry. At Vapourtec, we noticed this surge by the number of publications featuring our UV-150 photochemical reactor. Thanks to its homogeneous irradiation field and precise control of reaction parameters, the UV-150 was key for Professors Dave MacMillan, Peter Seeberger, Steven Ley, Cory Stephenson, Timothy Noël (and many others!) to explore photoredox catalysis in flow.
Stern-Volmer analysis and difficulties in batch
Stern-Volmer analysis in batch is a labour-intensive process, which requires a methodical approach and care for the results to be quantitative. A few factors account for its difficulty:
- Several solutions need to be made at different concentrations for the calibration range.
- Some solvents, such acetone, are efficient quenching species. Care needs to be exercise when cleaning and drying glassware (flasks, cuvettes, etc.)
- Oxygen is also a potent quencher, which can be difficult to exclude during transfer to a cuvette spectrophotometer.
A flow approach can simplify these experiments, minimising human error and keeping away quenchers such as acetone and oxygen. For that reason, Noël and co-workers developed a continuous‐flow platform for fluorescence quenching studies and Stern–Volmer analysis (Kuijpers et al., 2018). The team at the VilelaLab worked to implement this flow approach into a teaching laboratory session, in which the students would not only do quenching studies but would also learn how to work with a flow set-up.
Prof Filipe Vilela commented: “Stern-Volmer analysis is one of the teaching modules here at Heriot-Watt University. This was an opportunity to implement flow chemistry in one of my modules. It would ease the analytical work-up, as well as exposing our students to work with a flow system. We prepare this application note as a lab guide, so other academic colleagues can implement flow chemistry in their undergraduate teaching labs”.
To read this application note click here
To find out more about the UV-150 photochemical reactor click here