- SPE Cartridges
- Bulk Adsorbents
- HPLC Columns
- Drinking Water Analysis
- Ion Selective Sensors
Prof Stoll and United Science’s founder, Jon Thompson, have been collaborating for over a decade. Prof. Stoll works with United Science on surface chemistry, materials characterization, and novel materials. As an expert in liquid liquid separations science, Prof. Stoll is a leading researcher in the field of two dimensional liquid chromatography. Prof Stoll’s research interests extend to pharmaceutical, environmental, and clinical analysis.
Fast, comprehensive two-dimensional liquid chromatography
DR Stoll, X Li, X Wang, PW Carr, SEG Porter, SC Rutan
Journal of Chromatography A 1168 (1-2), 3-4
Fast, comprehensive two-dimensional HPLC separation of tryptic peptides based on high-temperature HPLC
DR Stoll, PW Carr
Journal of the American Chemical Society 127 (14), 5034-5035
Graphical method for understanding the kinetics of peak capacity production in gradient elution liquid chromatography
X Wang, DR Stoll, PW Carr, PJ Schoenmakers
Journal of Chromatography A 1125 (2), 177-18
Prof Bulhmann is the inventor of fluorous ion selective sensors and is a key advisor and consultant to United Science. Prof Buhlmann’s research group develops chemical sensors, with a particular view to environmental monitoring and implantation into the human body. Our research falls at the interface of analytical chemistry, materials sciences, and host-guest chemistry. While we collaborate with organic chemists whenever possible, my group has a history of organic synthesis when needed; as a result, we published also in journals such as Tetrahedron Letters, Tetrahedron, and Journal of Organic Chemistry. An emphasis of ongoing research direction is the development of potentiometric sensors based on ionophore-doped fluorous sensing membranes. My group pioneered fluorous ISE membranes in 2005 and has since shown that fluorous ISE membranes exhibit not only benefits in terms of biofouling but are also exceptionally selective, which has allowed us work with nano- and picomolar detection limits. Ongoing work uses such electrodes to study the toxicity of nanoparticles and to push detection limits to the attomole level. This work also benefits from my longstanding interest in quantitative ISE theory. My contributions to this field include the expansion of existing theory of (i) the optimum ratio of electrically charged ionophores and ionic sites, (ii) the lifetime of ISE based on electrically charged receptors, and (iii) a quantitative understanding of non-Nernstian responses of ISEs. A key interest lies in the selectivity optimization of sensors based on receptors that may form complexes of multiple stoichiometries.
Dr. Smith is Engineering manager for sorbents and sorbent materials. Trained as an inorganic synthetic chemist, Dr. Smith is well versed in unique sensor materials for oxygen. He is an expert in surface modification and bulk sorbent properties. Dr. Smith also has significant experience with systems integration and builds fully integrated reactors and fluidics systems.
1. Oxygen gas sensing by luminescence quenching in crystals of Cu (xantphos)(phen)+ complexes
CS Smith, CW Branham, BJ Marquardt, KR Mann
Journal of the American Chemical Society 132 (40), 14079-14085
CS Smith, KR Mann
Chemistry of Materials 21 (21), 5042-5049
3. Exceptionally Long-Lived Luminescence from [Cu (I)(isocyanide) 2 (phen)]+ Complexes in Nanoporous Crystals Enables Remarkable Oxygen Gas Sensing
CS Smith, KR Mann
Journal of the American Chemical Society 134 (21), 8786-8789
4. Molecular oxygen sensing utilizing crystalline copper (I) complexes
UNIVERSITY OF MINNESOTA
Dr. Chen is the lead applications manager for United Science. She is the world leading expert and inventor of novel carbonate/bicarbonate/ CO2 sensing materials and sensor systems. She holds a Ph.D. degree from the University of Minnesota and is a key driver in our ion selective electrodes and sensor program. Other areas of expertise include synthetic organic chemistry, novel transduction materials and devices, and membrane host guest chemistry. She is co-author of several publications including this introductory white paper on Ion Sensing technology:
Ion-Selective Electrodes With Ionophore-Doped Sensing Membranes. In Supramolecular Chemistry: From Molecules to Nanomaterials; Steed, A. W., Ed, Gale P., Ed; John Wiley & Sons, Ltd: New York, 2012; Vol. 5, 2539.
1. Chen, L. D., Mandal, D., Pozzi, G., Gladysz, J. A., Buhlmann, P. “Highly CO32–Selective Electrodes Based on Ionophore-Doped Fluorous Membranes” Accepted at JACS.
2. Buhlmann, P., Chen, L. D. In Supramolecular Chemistry: From Molecules to Nanomaterials; Gale, P. A.; Steed, J. W. Eds.; Wiley.
3. Chen, L. D., Mandal, D, Gladysz, J. A., Buhlmann, P. “Chemical Stability and Application of a Fluorophilic Tetraalkylphosphonium Salt in Fluorous Membrane Anion-Selective Electrodes” New. J. Chem.,2010, 34, 1867-1874.
Dr. Lai has spent the last eight years designing, developing, and testing novel sensors. She is an expert in ion selective membrane formulation, host guest chemistry, and data processing. As R&D Manager for United Science, Dr. Lai oversees the entire sensor development process from concept to feasibility. She is also the key leading expert in PFC and silver ion sensing.
1. Lai, C-Z.; Fierke, M. A.; Correa da Costa, R.; Gladysz, J. A.; Stein, A.; Bühlmann, P.;
Highly Selective Detection of Silver in the Low ppt Range with ISEs Based on Ionophore-
Doped Fluorous Membranes. Anal. Chem. 2010, 82, 7634-7640.
2. Lai, C-Z.; Reardon, M. E.; Boswell, P. G.; Bühlmann, P.; Coordinating Properties of
Perfluoro-15-Crown-5. J. Fluorine Chem. 2010, 131, 42-46.
3. Lai, C-Z.; Koseoglu, S. S.; Lugert, E. C.; Boswell, P. G.; Rábai, J.; Lodge, T. P.; Bühlmann,
P.; Fluorous Polymeric Membranes for Ionophore-Based Ion-Selective Potentiometry: How
Inert Is Teflon AF? J. Am. Chem. Soc. 2009, 131, 1598~1606.
4. Lai, C-Z.; Joyer, M. M.; Fierke, M. A.; Petkovich, N.; Stein, A.; Bühlmann, P.;
Subnanomolar Detection Limit Application of Ion-Selective Electrodes with Three-
Dimensionally Ordered Macroporous Carbon Solid Contacts. J. Solid State Electrochem.
2009, 13, 123~128.
5. Lai, C-Z.; Fierke, M. A.; Stein, A.; Bühlmann, P.; Ion-Selective Electrodes with Three-
Dimensionally Ordered Macroporous Carbon as the Solid Contact. Anal. Chem. 2007, 79,
Other Selected Relevant Publications
6. Fierke, M. A.; Lai, C-Z.; Bühlmann, P.; Stein, A.; Detailed Analysis of the Role of 3DOM
Carbon Solid Contacts in Ion-Selective Electrodes. Anal. Chem. 2010, 82, 680-688.
Summary: A strategic marketing professional with a strong technical background and industry experience in analytical instrumentation, in-vitro diagnostics, biotech, mining, and the homeland security markets. Market development experience includes M&A targeting & strategy formulation, and market research & plans. I have significant experience in worldwide business-to-business functions including product management, product development, technical sales, strategic marketing, and business alliance formation. International experience in Europe and Japan.
Areas of Expertise