ACS New York Section
Analytical Topical Discussion
Group
2008 Annual Report
Officers for 2008
Chairman
Robert P. Nolan, PhD
International Environmental Research Foundation
Post Office Box 3459
Grand Central Station
New York, NY 10063-3459
Tel/Fax (800) 709-0028 E-mail: rnolan@ierfinc.org
Chairman Emeritus
William E.L. Grossman
Department of Chemistry
Hunter College of The City University of New York
695 Park Avenue
New York, NY 10021
Tel (212) 772-5338/5330
Board
Thomas Kubic, Director and Program Chair
John Jay School of Criminal Justice of The City University of NY
899 Tenth Avenue
New York, NY 10019
David C. Locke, Chairman
Department of Chemistry
Queens College of The City University of New York
65-30 Kissena Boulevard
Flushing, NY 11367-1597
Tel (718) 997-3271
Urs Jans, Director
Department of Chemistry
The City College of The City University of New York
Convent Avenue & 138th Street
New York, NY 10031
Tel (212) 650-8369/6052 E-mail: ujans@ccny.cuny.edu
Emmanuel Chang, Director
Department of Chemistry
York College of The City University of New York
AC-3F01
Jamaica, New York 11451 E-mail: echang@york.cuny.edu
The Analytical Topical Group held 3 programs in 2008
and continues to benefit from improve attendance (consistently 20 or more)
and interest since the partnership was formed with John Jay School of Criminal
Justice. The students in the graduate program in analytical chemistry at The
City University of New York are required to attend the seminars and the forensic
science students from John Jay can get seminar credit for attending. We continue
to have little interest from the analytical chemist outside of academia.
A problem we are trying to address. We do have interest from the scientific
instrument companies to introduce there new technology to the topical group.
We find these lectures interesting and do attract outside attendance.
This year Dr. Emmanuel Chang from York College has
joined our Board of Directors. He will be inviting several speakers for
the spring 2010 program. He graduated from Rockefeller University and can
help in arranging lectures by local analytical chemists and visitors.
Wednesday – April 30, 2008, at 6 PM
The Graduate Center of the City University of New York
365 Fifth Avenue
New York, NY
Science Center Room 4102
In-situ
Fabrication of Conducting Polymer Nanocomposites for Biosensing Applications:
Multiple Roles of DNA Functionalized Carbon Nanotubes
Dr. Huixin He
Chemistry Department,
Rutgers University, Newark, NJ 07102
Conducting polymers are attractive for sensor applications
because their electronic and electrochemical properties are highly sensitive
to molecular interactions, which provide excellent signal transduction for
molecular detection. Among conducting polymers, polyaniline is unique since
it is environmentally stable and easy to fabricate. It has been applied
widely in chemical sensors but not as much in biosensors. The reason is
that native polyaniline is neither electrochemically active nor conductive
in neutral solutions, which is a prerequisite for biosensor applications.
It is also limited both in the variety of molecules that can be detected
and in the selectivity of the detection. Major breakthroughs in this field
were the discoveries of self-doped polyaniline and polyelectrolyte-anion-doped
polyaniline, which brought polyaniline into the biosensor field due to the
improved redox activity and conductivity in neutral pH solutions. However,
compared to the parent polyaniline, the electrochemical activity, conductivity,
and the chemical and mechanical stabilities of both self-doped polyaniline
and bulky polyelectrolyte-doped polyaniline are greatly reduced due to steric
effects.
Here we report that the stability of a self-doped polyaniline,
poly(anilineboronic acid) in this work, is greatly improved when it is polymerized
in-situ with ss-DNA-wrapped single walled carbon nanotubes (ss-DNA/SWNTs).
The conductivity and redox properties of the polyaniline backbone are conserved
in neutral solutions (pH = 7.4), and the sensitivity for biomolecular detection
is significantly enhanced. We found that the ss-DNA/SWNTs performed multiple
roles in the greatly improved properties of the self-doped polyaniline both
during and after the polymerization, which makes this work unique compared
to previously reported conducting polymer/carbon nanotube composites. First,
the ssDNA/SWNTs acted as effective catalytic molecular templates during
polymerization of self-doped polyanline so that not only was the polymerization
speed increased, but also the quality of the polymer was greatly improved.
Second, they functioned as novel active stabilizers after the polymerization,
which significantly enhanced the stability of the film. Furthermore, the
ss-DNA/SWNTs also acted as conductive polyanionic doping agents and conductive
bridges in the resulting polyaniline film, which showed enhanced conductivity
and redox activity. Finally, the large surface area of carbon nanotubes greatly
increased the density of the functional groups available for sensitive detection
of the target analyte.
Using this material, we developed a non-oxidative approach
to electrochemically detect neurotransmitter dopamine with extremely high
sensitivity. More importantly, since direct oxidation of dopamine on the
electrode was not involved in this sensing approach, its related problems
were thus avoided. The high sensitivity along with the improved selectivity
of this sensing approach may hold great promise for molecular diagnosis of
Parkinson's disease. Changing the functional groups along the polyaniline
backbone, we developed extremely sensitive approach for detection of trace
level neural toxins, which has been used as chemical warfare agents.
Biosketch: Dr. Huixin He received her PhD in
Peking University, China in 1997. She joined National University of Singapore
as a research associate, working mainly on plastic microfluid channels and
micropatterns by soft lithography. In 1999, she came to the United States
working with Professor Nongjian Tao, first in Florida International University
and then Arizona State University. At this period time, she was mainly working
on molecular electronics, including the electronic properties of metallic
quantum wires and single chain conducting polymer wires. In 2002, she joined
chemistry department, Rutgers University at Newark, as an assistant professor.
Her current research interests include conducting polymer nanocomposite, especially
in the fundamental study of interaction at interfaces in the composite and
exploration of the composite materials for chemical and biosensor applications.
She is also actively working on developing nonviral gene delivery system
using these nanocomposites and other nanomaterials.
Wednesday – March 19, 2007, at 6 PM
The Graduate Center of the City University of New York
365 Fifth Avenue
New York NY
Statistical Discrimination
of Gasoline Samples from Casework using GC-MS
Efforts to Meet the Daubert
Challenge
Dr. Nicholas D. K. Petraco
John Jay College of Criminal Justice
The intention of this study was to differentiate casework
liquid gasoline samples by utilizing multivariate pattern recognition procedures
on data from gas chromatography-mass spectrometry. A supervised learning
approach was undertaken to achieve this goal employing the methods of principal
component analysis, canonical variate analysis, orthogonal canonical variate
analysis and linear discriminant analysis.The study revealed that the variability
in the sample population was sufficient to distinguish all the samples from
one another knowing their groups a priori. Canonical variate analysis was
able to differentiate all samples in the population using only three dimensions
while orthogonal canonical variate analysis required four dimensions. Principal
component analysis required ten dimensions of data in order to predict the
correct groupings. These results were all cross-validated using the "hold-one-out"
method to confirm the classification functions and compute estimates of
error rates. These results have helped to develop procedures to use
multivariate analysis applicable to fire debris casework.
Biosketch: Nicholas D. K. Petraco earned a bachelor’s
degree in chemistry from Colgate University in 1998 and a doctorate in quantum
chemistry from the University of Georgia in 2002. He was a postdoctoral
fellow in applied mathematics at the University of Waterloo from 2002-2004
where after he was appointed to an assistant professorship in chemistry
at John Jay College of Criminal Justice and The Graduate Center, City University
of New York. His current research interests are in the application of statistical
pattern recognition methods to trace evidence. He is also interested in
the general application of mathematics and computers to physical evidence
analysis problems in forensic science.
Wednesday – December 17, 2008, at 6 PM
The Graduate Center of the City University of New York
365 Fifth Avenue, New York NY
Science Center Room 4102
Scientific Firearm and
Tool Mark Examination.
Peter Diaczuk
Director of Forensic Science Training,
Center for Modern Forensic Practice
John Jay College of Criminal Justice, CUNY.