Publications de Christophe Roussel

Heterogeneous Overhauser-DNP on H-1 dominated by scalar coupling in aqueous solution

Jean-Philippe Ansermet, Christophe Roussel, Felipe Andres Saenz Padilla, Jonas Milani

The Overhauser Dynamic Nuclear Polarization (O-DNP) of H-1 nuclei usually involves a dipolar coupling with the polarizing agent, whereas scalar coupling via hyperfine interactions are more common with C-13 nuclei. Here, we show a scalar-coupling dominated ...

WILEY2022

Blatter-type radicals as polarizing agents for electrochemical overhauser dynamic nuclear polarization

Jean-Philippe Ansermet, Holger Frauenrath, Christophe Roussel, Felipe Andres Saenz Padilla, Jonas Milani, Mika Antero Tamski

Overhauser dynamic nuclear polarization (O-DNP) refers to a microwave-assisted process where an unpaired electron's (e.g. a radical) spin polarization is transferred to surrounding nuclei in solution, thus increasing the nuclear magnetic resonance (NMR) si ...

Royal Society of Chemistry2022

Method for the preparation of a sample comprising highly polarized nuclear spins and uses and devices for such a method

Jean-Philippe Ansermet, Christophe Roussel, Jonas Milani, Mika Antero Tamski

Method for the preparation of a sample comprising highly polarized nuclear spins, comprising at least the following steps: a) bringing a polarization system, which using an electrochemical reaction can be converted into an EPR-active radical form thereof, ...

2021

Spin-dependent charge transfer at chiral electrodes probed by magnetic resonance

Jean-Philippe Ansermet, Christophe Roussel, Felix Blumenschein, Mika Antero Tamski

Chirality-induced spin selectivity is evidenced by exciting the spin resonance of radicals in an electrochemical cell where the working electrode is covered with a chiral self-assembled monolayer. Because the electron transfer to and from the paramagnetic ...

ROYAL SOC CHEMISTRY2020

Stabilization of p-GaAs electrode surfaces in organic solvent by bi-phenyl rings for spin dependent electron transfer studies

Jean-Philippe Ansermet, Christophe Roussel, Mika Antero Tamski

Biphenyl-4-thiol (B4t) functionalised p-GaAs photocathodes were compared to non-functionalised p-GaAs ones in the presence of methyl viologen cation radical (MV+•) as a redox mediator. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS ...

2020

Optimization of a Py-GC/MS method for silicone -based lubricants analysis

Christophe Roussel, Céline Burnier

Condom evidence can be analysed using several analytical techniques, such as FTIR, MALDI-MS or DART-TOF-MS, but the only one that was used on real samples for transfer and persistence studies in the context of sexual assault or rape cases was Py-GC/MS. How ...

2020

Electrochemical Overhauser dynamic nuclear polarization

Jean-Philippe Ansermet, Christophe Roussel, Jonas Milani, Mika Antero Tamski

Nuclear Magnetic Resonance (NMR) spectroscopy suffers from low sensitivity due to the low nuclear spin polarization obtained within practically achievable external magnetic fields. Dynamic Nuclear Polarization (DNP) refers to techniques that increase the N ...

2020

Quantification of THC in Cannabis plants by fast-HPLC-DAD: A promising method for routine analyses

Christophe Roussel, Céline Burnier

Nowadays, Gas Chromatography Mass Spectrometry (GC-MS) is mainly used in forensic sciences but suffers from limitations when the analysed compounds are thermally instable as it is the case for THC-A (Tetrahydrocannabinolic Acid) which is converted into Del ...

ELSEVIER SCIENCE BV2019

Probing charge transfer processes at p-GaAs electrodes under weak optical excitation

Jean-Philippe Ansermet, Christophe Roussel, Felix Blumenschein, Mika Antero Tamski

The p-GaAs photocathode/acetonitrile interface was characterised in the dark and with tens of mu W/cm(2) laser powers at 830 nm wavelength, using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Two redox mediators were used that p ...

2019

Thermal annihilation of photo-induced radicals following dynamic nuclear polarization to produce transportable frozen hyperpolarized 13C-substrates

Giovanni Boero, Andrea Capozzi, Christophe Roussel, Tian Cheng, Arnaud Comment

Hyperpolarization via dynamic nuclear polarization (DNP) is pivotal for boosting magnetic resonance imaging (MRI) sensitivity and dissolution DNP can be used to perform in vivo real-time 13C MRI. The type of applications is however limited by the relativel ...

Nature Publishing Group2017