The joint Â鶹AV/RSB Zoom webinar will be held on Wednesday 23 April 2025 from 18.30 til 19.30. Tickets can be booked using the booking link, with the login details sent in the confirmation email.
An abstract for the talk follows:
Understanding the light induced chemical pathways of Riboflavin (Vitamin B2)
Sarah A. Wilson,1 Ruby Spratt,1 Aljawharah Alsalem,1 Giel Berden,2 Jos Oomens,2 Ian J. S. Fairlamb,1 and Caroline E. H. Dessent1
1University of York, York, U.K.; 2Radboud University, Nijmegen, The Netherlands
Flavin compounds play a crucial role in biochemistry. They have a variety of different structures and functions in catalytic and photochemical processes where they serve as light-sensitive components in photoreceptors. Riboflavin, also known as vitamin B2, is a type of flavin found in foods such as meat and dairy. It helps maintain healthy skin, eyes, the nervous system, and mucous membranes.1,3 Riboflavin has been used as a photocatalyst in various catalytic reactions, so that it has emerged as a powerful and attractive metal-free photocatalyst.4
Riboflavin’s photochemical behavior is complex and depends on the chemical environment, such as pH, solvent and the wavelength of light which it is exposed to. These factors can change the reaction rates and the photoproducts which are formed.2,5
In this study we investigate the effects of UV light on riboflavin and its dimer complex (two molecules) under basic pH conditions. We used advanced instrumental techniques to introduce riboflavin into the gas phase where it can be studied in detail away from the complications of bulk condensed phase interactions. Time-resolved mass spectrometry (TRMS)6 is used to observe the photodecay of deprotonated riboflavin, photoproducts and reaction intermediates. Using gas-phase infrared multiple-photon dissociation IRMPD over the region 700 - 2000 cm−1 at the FELIX free-electron laser facility we are able to obtain the first gas-phase IR spectrum of deprotonated riboflavin, giving key insights to structure and deprotonation.7 Experimental results show that in solutions with near-neutral pH the riboflavin dimer (two molecules) is more stable than the monomer (one molecule), indicating
that it has a substantial role in the photodegradation pathway of a riboflavin solution. Hence the importance that the behavior of the riboflavin dimer is more fully understood. This approach provides novel structural insights into deprotonated RF, its dimers, photofragments, and intermediates, furthering our understanding of these crucial biochemical compounds.
Keywords: Time-resolved mass spectrometry, infrared multiple-photon dissociation, riboflavin, photochemistry, photodegradation, photocatalysis.
References:
(1) Ks, C.; Cc, M.; Br, C. Photochemistry of Flavoprotein Light Sensors. Nat. Chem. Biol. 2014, 10 (10). https://doi.org/10.1038/nchembio.1633.
(2) Knak, A.; Regensburger, J.; Maisch, T.; Bäumler, W. Exposure of Vitamins to UVB and UVA Radiation Generates Singlet Oxygen. Photochem. Photobiol. Sci. 2014, 13 (5), 820–829. https://doi.org/10.1039/c3pp50413a.
(3) O’Callaghan, B.; Bosch, A. M.; Houlden, H. An Update on the Genetics, Clinical Presentation, and Pathomechanisms of Human Riboflavin Transporter Deficiency. J. Inherit. Metab. Dis. 2019, 42 (4), 598–607. https://doi.org/10.1002/jimd.12053.
(4) Wong, N. G. K.; Rhodes, C.; Dessent, C. Photodegradation of Riboflavin under Alkaline Conditions: What Can Gas-Phase Photolysis Tell Us about What Happens in Solution? Mol. Basel Switz. 2021, 26. https://doi.org/10.3390/molecules26196009.
(5) Ahmad, I.; Fasihullah, Q.; Noor, A.; Ansari, I. A.; Ali, Q. N. M. Photolysis of Riboflavin in Aqueous Solution: A Kinetic Study. Int. J. Pharm. 2004, 280 (1), 199–208. https://doi.org/10.1016/j.ijpharm.2004.05.020.
(6) Thomas, G. T.; Donnecke, S.; Chagunda, I. C.; McIndoe, J. S. Pressurized Sample Infusion. Chemistry–Methods 2022, 2 (1), e202100068. https://doi.org/10.1002/cmtd.202100068.
(7) Berden, G.; Derksen, M.; Houthuijs, K. J.; Martens, J.; Oomens, J. An Automatic Variable Laser Attenuator for IRMPD Spectroscopy and Analysis of Power-Dependence in Fragmentation Spectra. Int. J. Mass Spectrom. 2019, 443, 1–8. https://doi.org/10.1016/j.ijms.2019.05.013.
An abstract for the talk follows:
Understanding the light induced chemical pathways of Riboflavin (Vitamin B2)
Sarah A. Wilson,1 Ruby Spratt,1 Aljawharah Alsalem,1 Giel Berden,2 Jos Oomens,2 Ian J. S. Fairlamb,1 and Caroline E. H. Dessent1
1University of York, York, U.K.; 2Radboud University, Nijmegen, The Netherlands
Flavin compounds play a crucial role in biochemistry. They have a variety of different structures and functions in catalytic and photochemical processes where they serve as light-sensitive components in photoreceptors. Riboflavin, also known as vitamin B2, is a type of flavin found in foods such as meat and dairy. It helps maintain healthy skin, eyes, the nervous system, and mucous membranes.1,3 Riboflavin has been used as a photocatalyst in various catalytic reactions, so that it has emerged as a powerful and attractive metal-free photocatalyst.4
Riboflavin’s photochemical behavior is complex and depends on the chemical environment, such as pH, solvent and the wavelength of light which it is exposed to. These factors can change the reaction rates and the photoproducts which are formed.2,5
In this study we investigate the effects of UV light on riboflavin and its dimer complex (two molecules) under basic pH conditions. We used advanced instrumental techniques to introduce riboflavin into the gas phase where it can be studied in detail away from the complications of bulk condensed phase interactions. Time-resolved mass spectrometry (TRMS)6 is used to observe the photodecay of deprotonated riboflavin, photoproducts and reaction intermediates. Using gas-phase infrared multiple-photon dissociation IRMPD over the region 700 - 2000 cm−1 at the FELIX free-electron laser facility we are able to obtain the first gas-phase IR spectrum of deprotonated riboflavin, giving key insights to structure and deprotonation.7 Experimental results show that in solutions with near-neutral pH the riboflavin dimer (two molecules) is more stable than the monomer (one molecule), indicating
that it has a substantial role in the photodegradation pathway of a riboflavin solution. Hence the importance that the behavior of the riboflavin dimer is more fully understood. This approach provides novel structural insights into deprotonated RF, its dimers, photofragments, and intermediates, furthering our understanding of these crucial biochemical compounds.
Keywords: Time-resolved mass spectrometry, infrared multiple-photon dissociation, riboflavin, photochemistry, photodegradation, photocatalysis.
References:
(1) Ks, C.; Cc, M.; Br, C. Photochemistry of Flavoprotein Light Sensors. Nat. Chem. Biol. 2014, 10 (10). https://doi.org/10.1038/nchembio.1633.
(2) Knak, A.; Regensburger, J.; Maisch, T.; Bäumler, W. Exposure of Vitamins to UVB and UVA Radiation Generates Singlet Oxygen. Photochem. Photobiol. Sci. 2014, 13 (5), 820–829. https://doi.org/10.1039/c3pp50413a.
(3) O’Callaghan, B.; Bosch, A. M.; Houlden, H. An Update on the Genetics, Clinical Presentation, and Pathomechanisms of Human Riboflavin Transporter Deficiency. J. Inherit. Metab. Dis. 2019, 42 (4), 598–607. https://doi.org/10.1002/jimd.12053.
(4) Wong, N. G. K.; Rhodes, C.; Dessent, C. Photodegradation of Riboflavin under Alkaline Conditions: What Can Gas-Phase Photolysis Tell Us about What Happens in Solution? Mol. Basel Switz. 2021, 26. https://doi.org/10.3390/molecules26196009.
(5) Ahmad, I.; Fasihullah, Q.; Noor, A.; Ansari, I. A.; Ali, Q. N. M. Photolysis of Riboflavin in Aqueous Solution: A Kinetic Study. Int. J. Pharm. 2004, 280 (1), 199–208. https://doi.org/10.1016/j.ijpharm.2004.05.020.
(6) Thomas, G. T.; Donnecke, S.; Chagunda, I. C.; McIndoe, J. S. Pressurized Sample Infusion. Chemistry–Methods 2022, 2 (1), e202100068. https://doi.org/10.1002/cmtd.202100068.
(7) Berden, G.; Derksen, M.; Houthuijs, K. J.; Martens, J.; Oomens, J. An Automatic Variable Laser Attenuator for IRMPD Spectroscopy and Analysis of Power-Dependence in Fragmentation Spectra. Int. J. Mass Spectrom. 2019, 443, 1–8. https://doi.org/10.1016/j.ijms.2019.05.013.
