Actinide and Lanthanide Chemistry

Room Temperature Ionic Liquids

Room temperature ionic liquids (RTIL) form potentially important solvents in novel nuclear waste reprocessing methods. We use infrared, Raman, and NMR spectroscopies to study the solvation, speciation, and complexation behaviors of actinides and lanthanides in these fascinating solvents. We are particularly interested in the interactions between water and metal ions in imidazolium-based RTIL. We are currently working to characterize uranyl(VI)-amidoxime complexes in aqueous solutions using ATR-FTIR and Raman spectroscopies. 

Mass Spectrometry 

The aquatic chemistry of uranium influences important technological, biological, and geochemical processes, including mobility  and fate in the geologic subsurface, bioavailability  and  carcinogenicity,  nuclear  fuel reprocessing,  and  the migration  of  nuclear  wastes. Ph.D. student Adetayo Mustapha is using electrospray ionization mass spectrometry to study uranium, vanadium, and iron complexes with amidoxime ligands that are used to adsorb uranium from seawater. Adetayo has also investigated the coordination of Ag+ and Cu2+ with phosphorothioate pesticides as a way to improve the detection of these pesticides using ESI-MS. Mustapha, A. M.; Pasilis, S. P.* Gas-Phase Copper and Silver Complexes with Phosphorothioate and Phosphorodithioate Pesticides Investigated using Electrospray Ionization Mass Spectrometry. J. Mass Spectrom. 2015, 50, 145-152. Mustapha, A. M.; Pasilis, S. P.* Probing Uranyl(VI) Speciation in the Presence of Amidoxime Ligands using Electrospray Ionization Mass Spectrometry. Rapid Commun. Mass Spectrom. 2013, 27, 2135-2142. Stark, T. D.*; Matsumoto, T.; Lösch, S.; Boakye, P. A.; Balemba, O. B.; Pasilis, S. P.; Hofman, T. Isolation and Structure Elucidation of Highly Antioxidative 3,8’’- linked Biflavanones and Flavanon-C-glycosides from Garcinia buchananii Bark. J. Agric. Food Chem. 2012, 60, 2053-2062. Boakye, P. A.; Stenkamp-Strahm, C.; Bhattarai, Y; Heckman, M. D.; Brierley, S. M.; Pasilis, S. P.; Balemba, O. B.* 5-HT3 and 5-HT4 Receptors Contribute to the Anti-motility Effects of Garcinia buchananii Bark Extract in the Guinea Pig Distal Colon. Neurogastroenterol. Motil. 2012, 24, e27-e40. Boakye, P. A.; Brierly, S. M.; Pasilis, S. P.; Balemba, O. B.* Garcinia buchananii  bark extract is an effective anti-diarrheal remedy for lactose-induced diarrhea. J. Ethnopharmacology. 2012, 142, 539-547. Pasilis, S. P.*; Blumenfeld, A. Effect of Nitrate, Perchlorate, and Water on Uranyl(VI) Speciation in a Room Temperature Ionic Liquid: A Spectroscopic Investigation. Inorg. Chem. 2011, 50, 8302-8307. Pasilis, S. P.* Desorption Electrospray Ionization Mass Spectrometry. Encyclopedia of Analytical Chemistry. Supplementary Volumes S1-S3. John Wiley & Sons, Ltd: Chichester, 2011. pp 1395-1415. Wai, C. M.*; Liao, Y. J.; Liao W. S.; Tian G. X.; Addleman R. S.; Quach, D.; Pasilis, S. P. Uranium Dioxide in Ionic Liquid with a Tri-n-butylphosphate-HNO3 Complex– Dissolution and Coordination Environment. Dalton Trans. 2011, 40, 5039-5045. Quach, D. L.; Wai, C. M.; Pasilis, S. P.* Characterization of Uranyl(VI) Nitrate Complexes in a Room Temperature Ionic Liquid Using Attenuated Total Reflection- Fourier Transform Infrared Spectrometry. Inorg. Chem. 2010, 49, 8568-8572. Pasilis S. P.*; Van Berkel, G. J.* Atmospheric Pressure Surface Sampling/Ionization Techniques for Direct Coupling of Planar Separations with Mass Spectrometry. J. Chromatogr. A  2010, 1217, 3955–3965. Pasilis S. P.; Van Berkel, G. J.* Modern Atmospheric Pressure Surface Sampling/Ionization Techniques in Mass Spectrometry. Encyclopedia of Spectroscopy and Spectrometry (2nd Ed.) 2010, 1544–1555. Please click here to see a complete list of my publications.

208-885-4014 Office: Renfrew 003 University of Idaho Department of Chemistry P.O. Box 442343 Moscow ID 84844-2343
Contact Information

B. S. Chemistry

San Francisco State


M. S. Hydrology  University of Arizona Ph. D. Chemistry  University of Arizona Postdoctoral Research Oak Ridge National Laboratory
Research Interests Analytical Chemistry Sofie P. Pasilis University of Idaho Department of Chemistry
Current Research Interests
Selected Publications

Fall 2014

Chem 303/307

Physical Chemistry Lab

Spring 2015

Chem 553

Separation Theory and


Chem 454 Instrumental Analysis
Recent Presentations
Mustapha, A. M. and Pasilis, S. P. Gas Phase Complexes formed between Amidoxime Ligands and Vanadium or Iron Investigated using Electrospray Ionization Mass Spectrometry. 63rd ASMS Conference on Mass Spectrometry and Allied Topics. St. Louis, MO, May 31–June 4, 2015. Joshi, R. and Pasilis, S. P. Lanthanum(III) Complexes with Tributylphosphate and Tributylphosphine Oxide in an Imidazolium-based Ionic Liquid. 248th National Meeting of the American Chemical Society, San Francisco, CA, August 10–14, 2014. Joshi, R. and Pasilis, S. P. Interaction of Phosphate Esters and Phosphine Oxides with Imidazolium-based Room Temperature Ionic Liquids. 247th National Meeting of the American Chemical Society, Dallas, TX, March 16–20, 2014. Mustapha, A. M. and Pasilis, S. P. Improved ESI-MS Detection of Phosphorothioate Pesticides through Complexation with Ag+ and Cu2+. Pittsburgh Conference 2014, Chicago, IL, March 2–6, 2014.