Irek Janik Technical University of Lodz, Poland, M.Sc.Eng. ('95) Technical University of Lodz, Poland, Ph.D. ('01) Tel. (574) 631-5464 e-mail: ijanik@nd.edu Radiation Initiated Processes in Aqueous Media

Scientific Interests


Kinetics and mechanisms of radical reactions ― experimental characterization of medium effects on radiolytic rates and yields.

Spectroscopy in extreme environments― Optical spectroscopy of water and transients in sub- and supercritical water.

Surface structure characterization of proteins by pused oxidation ― Hydroxyl radical footprinting is a valuable technique for studying protein structure, but care must be taken to ensure that the protein does not unfold during the labeling process due to oxidative damage.

Radiation chemistry of water soluble polymers ―
Characterization of radiation induced crosslinking and scission of polymers in aqueous media.

Recent Accomplishments | Top |

Primary radical rates in high temperature water ― The rates of several key reactions of primary transients in water have been determined up to supercritical temperatures.

VUV spectroscopy in high temperature water and aqueous solutions ― Setup for studies of electronic absorption of liquid water has been developed. We are interested in  investigation of the nature of the blue shift in highly compressible supercritical water (SCW) where the water density can be continuously tuned from vapor to high density fluid.

Protein footprinting ― Novel method for sub-microsecond hydroxyl radical protein footprinting has been developed. This method uses a pulsed electron beam to generate a high concentration of hydroxyl radicals by radiolysis of water. The results with ubiquitin and β-lactoglobulin A, demonstrate that one sub-microsecond electron beam pulse produces extensive protein surface modifications.  Highly reactive residues that are buried within the protein structure are not oxidized, indicating that the protein retains its folded structure during the labeling process. Our ability to heavily oxidize the protein without concern for oxidation-induced unfolding allows us to detect a much greater amount of oxidation than previously-reported results of the same protein, allowing for higher resolution hydroxyl radical protein footprinting data.

C. Watson, I. Janik, T. Zhuang, O. Charvatova, R. Woods and J. Sharp
Pulsed electron beam water radiolysis for sub-microsecond hydroxyl radical protein footprinting
Anal. Chem. 2009 81 2496-505 link

I. Janik, D.M. Bartels and C.D. Jonah
Hydroxyl radical self-recombination reaction and absorption spectrum in water up to 350 °C
J. Phys. Chem. A 2007 111 1835-43 link

D. Janik, I. Janik and D.M. Bartels
Neutron and beta/gamma radiolysis of water up to supercritical conditions.  1. Beta/gamma yields for H₂, H atoms, and hydrated electrons
J. Phys. Chem. A 2007 111, 7777-86 link

I. Janik, D.M. Bartels, T.W. Marin and C.D. Jonah
Reaction of O₂ with hydrogen atom in water up to 350 °C
J. Phys. Chem. A 2007 111 79-88

J. Bonin, I. Janik, D. Janik and D.M. Bartels
Reaction of the hydroxyl radical with phenol in water up to supercritical conditions
J. Phys. Chem. A 2007 111 1869-78

T. Schmidt, I. Janik, S. Kadlubowski, P. Ulanski, J.M. Rosiak, R. Reichelt and K.-F. Arndt
Pulsed electron beam irradiation of dilute aqueous poly(vinyl methyl ether) solutions
Polymer 2005 46 9908-18

I. Janik, E. Kasprzak, A. Al-Zier and J.M. Rosiak
Radiation crosslinking and scission parameters for poly(vinyl methyl ether) in aqueous solution
Nucl. Instr. and Meth. B 2003 208 374-9

Supported by the Division of
Chemical Sciences
Office of
Basic Energy Sciences
at the
U.S. Department of Energy

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Last Modified: 07/31/2009