NCSR

Research Interests:

My current research interests involve studying and development of potentiometric and optical sensors for environmental application. The simple construction, low cost and the possibility of miniaturization and remote control give these groups of sensors very attractive advantage compared to other well-established instrumental methods for routine analysis or in-situ measurements. My involvement in the current route in the development of optical sensors in the Adaptive Sensor Group assumes utilization of a family of organic molecules under the common name of spiropyrans. They undergo a reversible photoinduced transformation from a colorless, so-called ¿closed¿, spiropyran form to a colored, so-called ¿open¿, merocyanine form. When in open form, zwitterionic spiropyran possess ion-coordinating functional groups and is therefore potentially interesting as a ligand for charged species. Thus, light can control the binding but also delivery and transport. This is an attractive property in the means of remote controled chemical sensors or preconcentrators. Potentiometric sensors (Ion-selective electrodes (ISEs)) are a class of sensors that is lately receiving increased attention from the wider analytical chemistry community due to its significant advances in the last decade. From sensors with a mediocre detection limit (micromolar levels) they have been transformed into trace-level-analysis capable devices. Excellent detection limits, wide measurement range, simple construction, low cost and the possibility of miniaturization show great promise for the application of these sensors in the wide variety of fields.

Selected Peer Reviewed Journals

• McGraw Christina, Radu Tanja, Radu Aleksandar, Diamond Dermot;. 2008. Evaluation of liquid- and solid-contact Pb2+-selective polymer membrane electrodes for soil analysis. Electroanalysis, 20, 3, pp340-346.
• Radu, Aleksandar; Peper, Shane; Bakker, Eric; Diamond, Dermot. 2007. Guidelines for Improving the Lower Detection Limit of Ion-Selective Electrodes: A Systematic approach. Electroanalysis, 19, 2-3, pp144-154.
• Radu, Aleksandar; Scarmagnani, Silvia; Byrne, Robert; Slater, Conor; Lau, King-Tong; Diamond, Dermot. 2007. Photonic Modulation of Surface Properties: A Novel Concept In Chemical Sensing. Journal Of Physics D-applied Physics, 40, , pp7238-7244.
• Chumbimuni-Torres, Karin Y.; Rubinova, Nastassia; Radu, Aleksandar; Kubota, Lauro T.; Bakker, Eric. 2006. A Universal Recipe for Solid Contact Potentiometric Sensors with ppb Detection Limits. Analytical Chemistry, 78, 4, pp1318-1322.
• Radu, Aleksandar; Peper, Shane; Gonczy, Chad; Runde, Wolfgang; Diamond, Dermot. 2006. Trace-level Determination of Cs+ Using Membrane-based Ion-Selective Electrodes. Electroanalysis, 18, 13-14, pp1379-1388.
• Radu, Aleksandar, Bakker, Eric. 2005. Shifting the measuring range of chloride selective electrodes and optodes based on the anticrown ionophore [9]mercuracarborand-3 by the addition of 1-decanethiol. Chemia Analytyczna, 50, 1, pp71-83.
• Wygladacz, Katarczina; Radu, Aleksandar; Xu, Chao; Qin, Yu; Bakker, Eric. 2005. Microsensor array for trace analysis of silver. Analytical Chemistry, 77, 15, pp4706-4712.
• Radu Aleksandar; Amnon, J. Meir; Bakker, Eric. 2004. A dynamic diffusion model for tracing the real-time potential response of the polymer-based ion-selective electrodes. Analytical Chemistry, 76, 21, pp6402-6409.
• Sutter, Jolanda; Radu, Aleksandar, Peper, Shane; Bakker, Eric; Pretsch, Erno. 2004. A lead selective solid-contact polymeric membrane electrode with subnanomolar detection limit. Analytica Chimica Acta, 523, 1, pp53-59.
• Malon, Adam; Radu, Aleksandar; Qin, Wei; Qin, Yu; Ceresa, Alan; Maj-Zurawska, Magdalena; Bakker, Eric; Pretsch, Ernoe. 2003. Improving the Detection Limit of Anion-Selective Electrodes: An Iodide-Selective Membrane with a Nanomolar Detection Limit. Analytical Chemistry, 75, 15, pp3865-3871.
• Qin, Yu; Peper, Shane; Radu, Aleksandar; Ceresa, Alan; Bakker, Eric. 2003. Plasticizer-Free Polymer Containing a Covalently Immobilized Ca2+-Selective Ionophore for Potentiometric and Optical Sensors. Analytical Chemistry, 75, 13, pp3038-3045.
• Radu, Aleksandar; Telting-Diaz, Martin; Bakker Eric. 2003. Rotating Disc Potentiometry for Inner Solution Optimization of Low Detection Limit Ion-Selective Electrodes. Analytical Chemistry, 75, 24, pp6922-6931.
• Ceresa, Alan; Radu, Aleksandar; Peper, Shane; Bakker, Eric; Pretsch, Ernoe. 2002. Rational Design of Potentiometric Trace Level Ion Sensors. A Ag+-Selective Electrode with a 100 ppt Detection Limit. Analytical Chemistry, 74, 16, pp4027-4036.
• Micic, Miodrag; Markovic, Dragan; Vukelic, Nikola; Stamatovic, Aleksandar; Milosevic, Boris; Radu, Aleksandar; Polic, Predrag; Markovic, V.; Leblanc, Roger M. 2001. Gaseous and particulate sulfur in Belgrade troposphere. Fresenius Environmental Bulletin, 10, 7, pp629-634.
• Micic, Miodrag; Markovic, Dragan; Vukelic, Nikola; Radu, Aleksandar; Milosevic, Boris; Leblanc, Roger M. 2000. Environmental scanning electron microscopy study of commonly used filters substrates for the active sampling of atmospheric aerosols. Fresenius Environmental Bulletin, 9, 3-4, pp193-200.
• Radu, Aleksandar G.; Novakovic, Jovica M.; Milosevic, Dusanka I.; Miljevic, Nada R. 2000. Heavy metal pollution in the soil of fuel storage sites. Acta Periodica Technologica, 31, Pt B, pp539-545.

Selected Chapters

• Radu, Aleksandar; Diamond, Dermot. 2007. Ion-selective electrodes in trace level analysis of heavy metals: Potentiometry for the XXI century. Comprehensive Analytical Chemistry, Volume 49 Electrochemical Sensor Analysis, pp25-52.
• Radu, Aleksandar; Peper, Shane; Dermot Diamond. 2007. Determination of cesium in natural waters using polymer-based ion-selective electrodes. Comprehensive Analytical Chemistry, Volume 49 Electrochemical Sensor Analysis: Procedures, ppe13-e21.

• Radu, Tanja; Radu, Aleksandar; Diamond, Dermot, Ion-selective Electrodes with Polypyrrole- and Poly(3-octylthiophene)-Mediated Internal Solid Contact in Soil Analysis, In: Manfred Ehlers and Ulrich Michel ed.SPIE Europe, Remote Sensing, 17-SEP-07 - 20-SEP-07, Florence, Italy, 674922-1 - 674922-10
• Radu Aleksandar, Scarmagnani Silvia, Byrne Robert, Slater Conor, Alhashimy Nameer and Diamond Dermot, Photoswitcable surfaces: A new approach to chemical sensing, In: Manfred Ehlers and Ulrich Michel ed.SPIE Europe, Remote Sensing, 17-SEP-07 - 20-SEP-08, Florence, Italy, 67491Z-1 - 67491Z-10
• Radu, Tanja; Radu, Aleksandar; Christina McGraw; Dermot Diamond, Selective Electrodes As Simple And Inexpensive Detectors For Soil Analysis, In: T.D. Lekkas ed.10th International Conference on Environmental Science and Technology, 05-SEP-07 - 07-SEP-07, Cos Island, Greece, A1229 - A1236