METHOD DEVELOPMENT FOR DETECTION OF
DI(2-ETHYLHEXYL)PHTHALATE AND ITS METABOLITE
MONO(2-ETHYLHEXYL)PHTHALATE BY HPLC

Eva Navratilova Chugh
(evanavratilova@hotmail.com)

Thesis Advisor: Dr. John Albazi
Chemistry Department, Northeastern Illinois University
Chicago, Illinois

Di(2-ethylhexyl)phthalate (DEHP) is a benzenedicarboxilic acid ester which is the most widely used plasticizer to soften resins.  It can account for 40% or more of the weight of the plastic.  The worldwide production of DEHP reaches ~1 million tons per year, one third of which is based in the US.  DEHP is used for, among other applications, making the polyvinyl chloride (PVC) utilized in construction, wire insulation, food packaging, medical devices such as tubing and blood containers, cosmetics, toys, paints, and dielectric fluid in capacitors.

DEHP is hydrolyzed into what many believe to be its toxic metabolite, mono(2-ethylhexyl)phthalate (MEHP), by lipase enzymes in the gastrointestinal tract.  Due to the variety of metabolizing mechanisms across species, MEHP exhibits toxic effects in varying intensity on different tissues, depending upon the organism under examination.  The purpose of this study was to develop a method for detection of DEHP and MEHP in biological tissue.  This method can be used in the future to identify a correlation between DEHP exposure and toxic effects.

Reverse high-performance liquid chromatography (HPLC) was used as a method for detection of the two chemicals.  Under several methodological variables, including controlled pH of the mobile face, inclusion of different solvents for the sample, and introduction of an ion-pairing reagent, the best conditions for quantization of both chemicals was found.  Under these conditions, the estimated detection limits were determined to be 1 mg/L for DEHP and 100µg/L for MEHP.

A reproducible HPLC method was therefore developed for future use in determination of DEHP toxicity in laboratory animals. Future work would include validation of applicability in different tissues.

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Bioremediation: A look into the Process and Applications

Julia Markworth and Tom Weaver*
Department of Chemistry
Northeastern Illinois University
Chicago, IL 60625

In today’s quickly evolving world, with the rapid advances in the industrial and manufacturing companies, there comes with it an increase in the amount of contaminants and pollutants deposited into the environment. In order to protect the health of both humans and the environment, these potential harmful items need to be disposed of in a safe and efficient manner.   Traditional means of doing this involves removing contaminates and whatever they are located in, such as soil, and isolation of the compounds.  This is done to insure that contaminates do not reach dangerous levels and/or contaminate or pollute crops, water supply, or the air.  These traditional methods can be both costly and time consuming.  In the growing populous of the earth, a more efficient and environmentally friendly method of removing contaminants and pollutants needs to be considered.

Bioremediation is the process of using naturally occurring microorganisms to remove contaminants in the environment by breaking them down or capturing them.  An extension of the remediation process involves the use of plants in the uptake of toxic compounds and elements; called phytoremediation.  We explore the process and applications of Bioremediation in its role in environmental clean up.  A brief exploration of the newer study of phytoremediation will also be considered.

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IMMUNOCHEMICAL METHODS IN IMMUNOASSAYS: DETECTION OF HIV RETROVIRAL DRUG INDINAVIR

Ingrid J. Leal and Pratibha Varma-Nelson*
Department of Chemistry
Northeastern Illinois University
Chicago, IL 60625

When foreign bodies, such as proteins or sugars (antigens) are introduced to the body the immune system produces antigen specific antibodies to these. These antibodies can be harvested and used to develop immunoassays. Immunoassays are laboratory methods that are commonly used by clinicians to monitor and quantitatively detect the amount of a drug in a patient’s blood.  Monitoring blood drug concentration has proved to be valuable in HIV treatment. Inexpensive convenient immunoassays for HIV retroviral drugs are not available.

The aim of this research is to develop an immunoassay for the HIV protease inhibitor indinavir (Crixivan®).  We are currently coupling indinivir to bovine serum albumin.  This is to be used to immunize yolks.  Anti-indinivir antibodies will be isolated from eggs, purified and used to establish an indinivir assay.

Thus far, indinivir has been purified, succinylated and coupled to bovine serum albumin.  Protocols for isolation, purification and quantization of IgY have been tested and refined.  Techniques used in this research include ammonium sulfate IgY precipitation, Sephadex gel filtration chromatography, gel electrophoresis protein separation and staining.  Indinavir purification and chemical reactions have been confirmed through a combination of Thin Layer Chromatography (TLC), Infrared (IR) spectroscopy and Nuclear Magnetic Spectroscopy (NMR) methods.

Updated 11/4/04