Pusan National University, S. Korea
Prof. Yoon-Bo Shim has completed his PhD at 1985 from Pusan National University and postdoctoral studies from University of New Mexico (USA). His major is analytical chemistry and electrochemistry. He is a professor of chemistry department and the director of Institute of BioPhysio Sensor Technology at Pusan National University. He has published more than 280 papers in reputed journals and has been serving as editorial board members of Electroanalysis, Sensor, Chemosensor.
An on-chip preconcentration, separation, and electrochemical detection method was developed for the simultaneous determination of endocrine disruptor (ED), phthalate esters using a microfluidic channel device. The electrochemical analysis of phthalate esters in aqueous media is difficult using conventional methods due to the extremely negative potential for the reduction of them. Thus, the sensor probe layer was assembled with dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) and toluidine blue O (TBO) on the conductive polymer layer to capture and reduce the EDs on the probe through the control of the surface charge and hydrophobic properties. Terthiophene benzoic acid was synthesized and electrochemically polymerized, then a DOPE and TBO were chemically bonded together on polyTTBA. The modified sensor probe shows the reduction peak of phthalate esters around -1.6 V in 0.1 M buffer solution (pH 10.0), while the bare electrode doesn’t show any redox peak of them. The sensor probe was firstly examined for the electrochemical detection of five phthalate esters using voltammetry and chronoamperometry. Then, the microfluidic channel coupled with the sensor probe was used for the simultaneous analysis of them. Experimental parameters affecting the analytical performance were assessed and optimized in terms of ratio of DOPE:TBO (v/v%), detection potential, pH, and running buffer concentration. The dynamic linear range and detection limits were 0.15 nM - 1.0 µM and 12.5 ± 1.5 pM with relative standard deviations of <5%. The reliability of the proposed method was evaluated with real environmental samples that show excellent performance for the analysis of a phthalate ester family, one of major EDs.