Using LC-MS & GC-MS to Decode Photoredox Catalyst Stability скачать в хорошем качестве

Using LC-MS & GC-MS to Decode Photoredox Catalyst Stability

In this episode of Concentrating on Chromatography, we sit down with Lindsay Repka to discuss how LC-MS and GC-MS transformed her lab’s approach to photoredox chemistry. What began as a project to develop a visible-light photocrosslinking handle unexpectedly led to a major discovery: the solvent (DMF) was reacting with the photocatalyst itself. Using high-resolution LC-MS, Lindsay’s team observed multiple solvent adducts forming — sometimes with complete catalyst consumption. That discovery reshaped their research direction. Drawing from her ACS Northeast presentation and this in-depth conversation, Lindsay explains: 🔬 How photoredox catalysts become activated under visible light 📊 Why LC-MS was essential when NMR couldn’t resolve complex mixtures 📈 How to design reproducible calibration curves for percent catalyst remaining 📉 Why extracted ion chromatograms (EIC) outperform total ion chromatograms (TIC) at low concentrations ⚗️ How solvent activation chemistry led to selective N-demethylation 🧪 Why GC-MS with an internal standard streamlined reaction screening 📐 What relative response factors mean — and why they can’t always be assumed constant 🧑‍🔬 Practical tips for improving reproducibility (microbalances, deoxygenated solvents, temperature control) This episode is a rare deep dive into both LC-MS and GC-MS within the same research project, showing how chromatography-driven insight can turn unexpected degradation into productive new reactivity. If you work in: Photoredox chemistry Reaction optimization Mass spectrometry method development Catalyst screening Academic synthetic chemistry …this conversation will resonate. 🧪 Key Topics Covered Photocatalyst stability in DMF, DCE, and MeCN Demethylation under mild visible-light conditions High-resolution Q-TOF LC-MS quantitation Internal standard methodology in GC-MS Signal-to-noise improvement using extracted ion chromatograms Reaction reproducibility and quality control strategy 🎙 About the Guest Lindsay Repka is a chemistry professor at Middlebury College whose research explores photoredox chemistry, catalyst stability, and visible-light-driven transformations. Her lab emphasizes both mechanistic insight and hands-on student training in advanced analytical instrumentation. If you enjoy conversations at the intersection of chromatography and real-world chemistry research: 👍 Like 💬 Comment with your LC-MS / GC-MS questions 🔔 Subscribe for more episodes of ‪@ChromatographyTalk‬​