Dr. Debra Van Engelen

Most ongoing undergraduate research projects under my supervision study specific applications of high-resolution separations and sensitive, selective spectrometric measurements of trace levels of analytes in complex environmental or biological samples.

Recently, we have used normal-phase chiral stationary phases to separate enantiomers and monitor reaction dynamics by High Performance Liquid Chromatography (HPLC). We also use HPLC at different temperatures to study the thermodynamics of interactions between a compound and the chromatographic stationary phase. In addition, we use HPLC chromatography to estimate physical constants such bioconcentration factors.

Reactions that have previously been useful for chemical derivatization of compounds to be separated by HPLC are being studied and adapted for use with capillary electrophoresis (CE). Previously, my research students have constructed a site-built CE system with laser-induced fluorescence (LIF) detection. For substances that do not exhibit native fluorescence, derivatization reactions may be used to enhance detection sensitivity for CE. The goal of this work is to enhance the intensity of the fluorescence signal produced by the reaction for a particular molecule without significantly reducing the separation efficiency.

My research group is has designed and constructed a Raman spectrometer with an argon ion laser as the radiation source. Future studies involve development of new analytical method using resonance Raman spectrometry for specific analytical problems.

Over the years, I have also supervised many students on projects relating to analysis of environmental pollution and remediation. One area of our current research in environmental chemistry is phytoremediation of contaminated soil or solutions by plants that hyperaccumulate heavy metals. Recently, we have initiated studies using ion chromatography, gas chromatograph with mass spectrometry, and HPLC with mass spectrometry to determine the effects of air pollution on native California plants.

With my chemical education students (i.e. future teachers), we develop curricula which guide students from traditional experiments with passive learning to becoming more active learners who design, interpret, and report on experiments in an increasingly independent manner. Attitudes about science, their self-perceived capabilities, and aspirations are monitored with surveys and correlated with learning outcomes.