Dale D. Russell

Mercury selective electrode

The present invention is an apparatus for laboratory and field use in detecting and measuring Hg+ and Hg2+ in sample. A selective mercury binding agent, such as a chelating agent or clathrating agent, is covalently bound in a copolymer and deposited as an electrode layer. To prepare the preferred apparatus of the invention, thiophene, or other, similar monomer, is derivatized by covalent attachment thereto of Kryptofix-21™ (1,4,10-trioxa-7,13-diazacyclopentadecane) in the 3-position. The thiophene monomer and Kryptofix-21™ are co-polymerized and electrodeposited by known techniques onto a conductive substrate, such as platinum or glassy carbon, to obtain a multi-layer polymer coating of desired thickness. The resulting coated electrode has selective coordination sites for mercury of the order of Kf=1016, compared to Kf=103 for cadmium, Kf=105 for lead and Kf=105 for silver. Therefore, the resulting probe is very selective for mercury, compared to cadmium, lead and silver.

Separation of Charged Latex Particles by Electrical Field-Flow Fractionation

Abstract The retention of both underivatized and carboxylated polystyrene latex beads by electrical field-flow fractionation (EIFFF) was investigated using a 2 mM aqueous solution of quinonehydroquinone as the carrier liquid. The quninone-hydroquinone redox couple passes current with less polarization of the electrodes than carrier liquids previously employed. Underivatized beads, ranging in diameter from 0.15 to 0.74 μm eluted in the normal mode, while carboxylated beads larger than 1 μm eluted in the steric mode. Normal mode retention increases with flow rate, probably due to shearing of the polarization layer, which increases the working field. At a constant field and flow rate, normal-mode retention is inversely related to the product of a particles size and electrophoretic mobility, in accordance with retention theory. Thus, ElFFF can be used to obtain both the size and electrophoretic mobility of particle suspensions.

Modeling and design of polythiophene gate electrode ChemFETs for environmental pollutant sensing

Water-borne pollutants such as volatile organic compounds are a serious environmental concern, which has increased the demand for chemical sensing elements. Solid-state sensors based on catalytic gate devices are a subject of current research, however they are restricted in practical applications because of their inability to operate at room temperature. Conducting polymer FETs, which employ a conducting gate polymer, have received much attention due to their unique electronic and optical properties. Polythiophene is chosen as the semi-conductive gate polymer in this work. A functional group attached to the polythiophene is used to detect analytes (i.e., mercury in this work) of interest. The selectivity of the derivitized polythiophene to mercury can be rationalized based on the size of the ring, presence of oxygen and nitrogen donor atoms. In this paper, the modeling and design of a polythiophene gate electrode ChemFET will be discussed. Specifically the model development and resultant device simulations using Silvaco TCAD will be presented. Using this model various current-voltage characteristics of the ChemFET corresponding to parameters such as substrate doping, gate oxide thickness, various gate stacks, and device geometries are presented.

Undergraduate research opportunities in microelectronics at Boise State University

Several opportunities exist for undergraduates in the microelectronics area at Boise State University. This paper describes the Research Experience for Undergraduates (REU) program funded by the National Science Foundation and other opportunities that have resulted for undergraduates due to external support. BSU became a NSF REU site for microelectronics research in 1999. Each year, 10 students are recruited nationwide from various engineering and science disciplines to come to BSU for 8 weeks. The students work intensively with various faculty advisors and graduate student mentors. Another unique feature of our program is the tie to local industry. In 1999-2001, three students have and will benefit from an interaction with a local company, SCP Global Technologies, and this is described.