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Edward Zellers

Edward T. Zellers, Ph.D.

Professor, Environmental Health Sciences

Professor, Chemistry

M6543 SPH II      Vcard icon
1415 Washington Heights
Ann Arbor, Michigan 48109-2029

Office: (734) 936-0766; Fax: (734) 763-8095

E-mail: ezellers@umich.edu

Website(s): Research Lab: Integrated Environmental Microsystems

Professional Summary

Professor Zellers' research and teaching programs are concerned with various aspects of characterizing and controlling human exposures to toxic chemicals, including sampling and analytical methods and instrumentation, assessment strategies, and protective equipment. His primary research interests are in the development of microfabricated sensor arrays and integrated microanalytical systems for the direct determination of organic compounds in air and biological media and for characterizing the interfacial interactions of such compounds with various media. Among the applications being pursued for these new chemical sensing technologies are miniaturized, wireless instrumentation for indoor-air quality assessments, personal-exposure monitoring, breath analysis, ambient air pollution mapping, and in-situ assessments of the barrier effectiveness of polymeric chemical protective clothing. Prof. Zellers maintains an active interdisciplinary research group that involves collaborations among students, faculty, and research scientists from several UM departments, national laboratories, and small R&D firms. He teaches lecture and laboratory courses on chemical hazard evaluation, exposure assessment, and chemical microsensors and microsystems. As director of the Occupational Health Program, Dr. Zellers administers the industrial hygiene component of the NIOSH-funded Education and Research Center Training Grant. He is a member of the faculty in the Department of Chemistry and also serves as a Group Leader in the NSF-funded Engineering Research Center for Wireless Integrated MicroSystems (WIMS) headquartered in the Department of Electrical Engineering and Computer Science.

Courses Taught

EHS652: Evaluation of Chemical Hazards
EHS653: Environmental Sampling and Analysis Laboratory

Education

Ph.D., Environmental Health Sciences, University of California, Berkeley, 1987
M.S., Environmental Health Sciences, University of California, Berkeley, 1984
B.A., Chemistry, Rutgers University, 1978

Research Interests & Projects

> > Zellers Lab - Integrated Environmental Microsystems (Leader)

The assessment of human exposure to complex mixtures of natural and anthropogenic chemicals ranks among the most important global environmental health challenges. Our ability to meet evolving needs in this area relies critically on innovations in exposure science and technology. Advances that facilitate accurate, high-resolution measurements are integral to mankind's efforts to unravel the intricate relationships between exposure and the risks of adverse health effects, and to minimize such risks.Professor Zellers' research and teaching interests lies at the ... More >>

Integrated Environmental Microsystems 

> > Reliability of microfabricated GC columns (Principal Investigator)

The aims of this projects are to assess the consistency of chromatographic resolution achievable from multiple microfabricated glass/Si separation columns statically coated with non-polar and polar stationary phases, to develop better polar and non-polar techniquies with surface pre-treatment methods and to evaluate the effect of thermal cycling on an air matrix. A series of 3-meter and 1-meter columns were coated statically with the non-polar polydimethyl-siloxane or the moderately polar trifluoropropylmethyl-siloxane. Golay plots are used to assess column efficiency. Figure 1 ... More >>

Reliability of microfabricated GC columns 

> > Microscale Integrated Sampler-Injector (MISI) for a microGC (Principal Investigator)

The goals of this project are to design, fabricate, and evaluate the performance of a prototype MISI, assess performance relative to theoretical models of diffusional transport and adsorbent capacity for vapors commonly found as contaminants in indoor working environments, and interface the sampler with an array of microsensors to determine the feasibility of incorporating the MISI into a microanalytical system for near-real-time vapor determinations.... More >>

Microscale Integrated Sampler-Injector (MISI) for a microGC 

> > Chemometrics for detection of VOC by a microanalytical system (Principal Investigator)

This project seeks to develop chemometric method to guide the development and allow the implementation of a miniaturized gas chromatography system for the detection of volatile organic chemicals in the workplace or general environment.... More >>

Chemometrics for detection of VOC by a microanalytical system 

> > Thiolate-Monolayer-Protected Gold Nanoparticle Sensor Films for Explosives Detection (Principal Investigator)

Chemiresistor (CR) sensor arrays employing thiolate-monolayer-protected gold nanoparticles (MPNs) as interfacial films are being developed for the selective detection of explosives and tagants. Hexafluoro-alcohol functionalized MPNs (HFA-MPNs) are being incorporated into CR arrays because of their affinity for the nitro-aromatic functionality present in many explosives. Composite films of HFA-MPNs and nitrodiphenylacetylene-functionalized MPNs (NDPA-MPNs) are also being investigated. These films are expected to form a hydrogen-bonding network that would be disrupted selectively when a nitro-aromatic compound partitions into ... More >>

Thiolate-Monolayer-Protected Gold Nanoparticle Sensor Films for Explosives Detection 

> > Breath Biomarker Determinations with a Portable Gas Chromatograph (Principal Investigator)

This project is aimed at adapting a high-performance prototype portable gas chromatograph (GC) to the detection of volatile organic compounds (VOCs) in exhaled human breath. The instrument incorporates a detector consisting of an integrated array of chemiresistors (CR) coated with functionalized nanoparticles that respond differentially to sorbed vapors to produce a response pattern that aids in vapor recognition. Breath VOC profiles can be correlated with an individual's current health status, pre-clinical metabolic abnormalities, prescription drug effectiveness, and/or the presence ... More >>

Breath Biomarker Determinations with a Portable Gas Chromatograph 

> > Designed Materials for an Integrated Vapor Preconcentrator (Principal Investigator)

This project seeks to specify the optimal quantities and types of high-surface-area adsorbent materials for the u-preconcentrator/focuser (uPCF) module of the WIMS uGC, and to define the optimal operating conditions for the uPCF.... More >>

Designed Materials for an Integrated Vapor Preconcentrator 

> > Multi-Transducer Arrays for a uGC Detector (Principal Investigator)

In this project we are exploring alternative detectors for the WIMS uGC that consist of arrays microsensors that operate on different transduction principles. Chemiresistors (CR), thickness-shear mode resonators (TSMR) and film bulk acoustic resonators (FBAR) are being studied. Each is coated with a film of a functionalized thiolate-monolayer-protected gold nanoparticle (MPN), which serves as the partially selective interfacial sensing layer. Each type of sensor responds to different perturbations in the films upon reversible sorption of target vapors ... More >>

Multi-Transducer Arrays for a uGC Detector 

> > Rapid Determination of Environmental Tobacco Smoke Markers at Parts-Per-Trillion Levels (Principal Investigator)

Environmental tobacco smoke (ETS) is a complex mixture of compounds collectively classified by the International Agency for Research on Cancer as a carcinogenic substance. The complexity of ETS and the presence of confounding sources of some ETS constituents in many environments have impeded accurate exposure assessments and have led to efforts to find surrogate measures of ETS contamination levels. Two such markers are 3-ethenylpyridine (3-EP) and 2,5-dimethylfuran (2,5-DMF). In a study completed this past year, selective preconcentration, ... More >>

Rapid Determination of Environmental Tobacco Smoke Markers at Parts-Per-Trillion Levels 

> > Multi-Transducer Arrays Enhance Determinations of Vapor Mixtures (Principal Investigator)

In most applications of microfabricated sensor arrays to multi-vapor analysis, the devices employed operate on the same transduction principle. It stands to reason that arrays incorporating sensors that operate on different transduction principles should enhance response diversity by probing different aspects of the vapor-interface interaction and, thereby, improve vapor discrimination. This study explored and compared capabilities for vapor recognition and quantification with polymer-coated single-transducer (ST) multi-transducer (MT) arrays. The micrograph to the right shows an MT array chip ... More >>

Multi-Transducer Arrays Enhance Determinations of Vapor Mixtures 

> > Limits of Recognition for Multi-Transducer Arrays (Principal Investigator)

In the vast majority of studies of microfabricated sensor arrays for analyses of volatile organic compounds (VOC) the sensors employed in the arrays operate on the same transduction principle. With most of these single-transducer (ST) arrays, a thin interfacial film of a sorptive polymer serves to reversibly concentrate vapors near the surface of each sensor. It stands to reason that arrays of transducers operating on different principles, which we refer to as multi-transducer (MT) arrays, should enhance the capability ... More >>

Limits of Recognition for Multi-Transducer Arrays 

> > Fundamental Studies Impact the Design and Performance of a Multi-Stage Micro-Preconcentrator (Principal Investigator)

Most anticipated applications of micro-analytical systems to environmental monitoring require detection of target compounds in the parts-per-billion or parts-per-trillion concentration range. Since detector technologies are not sensitive enough to achieve limits of detection in this range, it is necessary to employ a preconcentration step prior to separation and detection. The microfabricated adsorbent preconcentrator/focuser (uPCF) we are developing for the WIMS uGC serves this purpose. This year we have completed a project concerned with the modeling and characterization of ... More >>

Fundamental Studies Impact the Design and Performance of a Multi-Stage Micro-Preconcentrator 

> > Reliable and Efficient Separation Columns with Thermally Stable Stationary Phases (Principal Investigator)

Among the most critical factors affecting the performance of the WIMS uGC relate to the DRIE-Si/glass channels used as gas chromatographic (GC) separation microcolumns, specifically, the consistency and uniformity of stationary phase deposition, deactivation of surface-adsorption sites on the microcolumn walls, and the stability of the stationary phase following repeated thermal cycling. This year, we demonstrated that films of PDMS can be reliably and reproducibly deposited in microcolumns 0.5 to 3-m long and cross-linked in situ to provide unprecedented ... More >>

Reliable and Efficient Separation Columns with Thermally Stable Stationary Phases 

> > A Low-Volume Low-Power Preconcentration and Gas Separation System (Principal Investigator)

This project is developing the next-generation gas separation/ analysis system for the WIMS uGC. The three-chip microsystem is being designed to minimize mass to permit high-speed temp-erature programming and is ther-mally-isolated for very low operating power. The chips plug directly together to eliminate any external tubing, avoiding the cold-spots, dead volumes, and band broadening it can cause.... More >>

A Low-Volume Low-Power Preconcentration and Gas Separation System 

> > A MEMS Micro Gas Chromatograph (Principal Investigator)

The determination of complex mixtures of toxic gases and vapors remains a challenging analytical problem of critical importance in human exposure assessments, industrial emission monitoring, biomedical surveillance and diagnosis, and homeland security. To address this problem, we are developing a wireless MEMS micro-GC (uGC) that includes a sample inlet with particulate filter, passive calibration-vapor source, multi-stage preconcentrator/focuser (uPCF), dual-column separation module with pressure- and temperature-programmed separation tuning, an array of microsensors for analyte recognition and quantification, system pressure and temperature ... More >>

 

> > The University of Michigan Education and Research Center (Co-Principal Investigator)

The University of Michigan Center for Occupational Health and Safety Engineering (COHSE), a NIOSH-funded Education and Research Center (ERC), provides comprehensive professional and research training in Industrial Hygiene (IH), Occupational Health Nursing (OHN), Occupational Safety Engineering and Ergonomics (OSE), Hazardous Substances Academic Training (HSAT), Occupational Epidemiology (OE), and Pilot Project Research Training (PPRT). We have functioned as an ERC since 1982. The ERC provide direct funding of Masters and doctoral students, as well as pilot research projects, and generally ... More >>

The University of Michigan Education and Research Center 

Selected Publications

Search PubMed for publications by Edward Zellers >>

Scholten, K., X. Fan and E.T. Zellers (2011). A Microfabricated Opto-fluidic Ring Resonator Applied Physics Letters, Accepted for publication, September, 2011

Kim, S.K., H. Chang and E.T. Zellers (2011). Microfabricated gas chromatograph for the selective determination of trichloroethylene vapor at sub-parts-per-billion concentrations in complex mixtures Analytical Chemistry, Web Publication, August 22, 2011, DOI:10.1021/ac201788q.

Scholten, K. F.I. Bohrer, G. Datoli, W. Lu and E.T. Zellers (2011). Organic Vapor Discrimination with Chemiresistor Arrays of Temperature Modulated Tin-Oxide Nanowires and Thiolate-Monolayer-Protected Gold Nanoparticles Nanotechnology, 22, 125501.

Bohrer, F.I., E. Covington, C. Kurdak and E.T. Zellers (2011). Characterization of Dense Arrays of Chemiresistor Vapor Sensors with Sub-Micron Features and Patterned Nanoparticle Interface Layers, Anaytlical Chemistry, 83(10), 3687-3695.

Sukaew, T., H. Chang, G. Serrano and E.T. Zellers (2011). A Multi-Stage Preconcentrator/ Focuser Module Designed to Enable Trace-Level Determinations of Trichloroethylene in Indoor Air with a Microfabricated Gas Chromatograph Analyst, 136(8), 1664-1674.

Steinecker, W.H., S.K. Kim, F.I. Boher, L. Farina, C. Kurdak and E.T. Zellers (2011). Electron-Beam Patterned Monolayer-Protected Gold Nanoparticle Interface Layers on a Chemiresistor Vapor Sensor Array 469-480, IEEE Sensors Journal, 11(2).

Kim, S.J., G. Serrano, K. Kirabayashi and E.T. Zellers (2011). Characterization of a microfabricated thermal modulator for comprehensive two-dimensional gas chromatography Analytical Chemistry, 83, 5556-5562.

Covington, E., F.I. Bohrer, C. Xu, E.T. Zellers and C. Kurdak (2010). Densely Integrated Array of Chemiresistor Vapor Sensors with Electron-Beam Patterned Monolayer-Protected Gold Nanoparticle Interface Films Lab On A Chip, 10, 3058-3060.

Kim, S.J., S.M. Reidy, B.P. Block, K.D. Wise, E.T. Zeller and K. Kurabayashi (2010). Microfabricated Thermal Modulator for Comprehensive Two-Dimensional Micro Gas Chromatography: Design, Thermal Modeling, and Preliminary Testing Lab In A CHip, 10, 1647-1654.

Zhong, Q., Steinecker, W. and Zellers, E.T. (2009). Characterization of a High-Performance Portable GC with a Chemiresistor Array Detector Analyst, 283-293.