SEERC FUNDED PROJECTS:
Equipment and Infrastructure
Participants
Faculty: Dayakar Penumadu (Professor, Civil and Environmental Engineering; Lead),
Barry Bruce (Biochemistry, Cellular, and Molecular Biology),
Bamin Khomami (Chemical and Biomolecular Engineering)
Function
This instrument is used for making static, dynamic, Absolute Size Exclusion Chromatography (ASEC) and electrophoretic light scattering measurements for determining size, distribution, molecular weight and zeta potential. Additionally, patented backscatter optics technology allows the Zetasizer Nano to have the highest sensitivity of any Dynamic Light Scattering (DLS) instrument while covering the broadest sample concentration range.
The instrument also has available patented, disposable zeta potential cells that are unique and eliminate sample cross-contamination and eliminate the need for washing/cleaning zeta potential cells/electrodes. This cell is a flow-through design also capable of connecting with the Malvern MPT-2 autotitrator for determining the relationship between zeta potential and pH (or any other titratable function).
More information regarding the specifications of this equipment may be found at www.malvern.com/zetasizernano.
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Participants
Faculty: Paul Frymier (Chemical and Biomolecular Engineering; Lead),
Barry Bruce (Biochemistry, Cellular, and Molecular Biology)
Graduate Student: Jared Graves (Chemical and Biomolecular Engineering)
Description
The kinetics of photosystem re-reduction are measured using a technique called laser flash photolysis. In this assay, a laser is used to photo-oxidize the photosystem (photosystem I in this case). A measuring or probe beam from an arc lamp is usually used to quantify the degree of photobleaching as a function of time. In our system, we use a Spectra Physics Indi-10 Nd:YAG laser with the first harmonic frequency doubler to provide light at 532 nanometers to excite photosystem I. Our measuring beam is provided by a 150W Xenon arc lamp, appropriately filtered through a monochromater (Newport Corporation Cornerstone 260) and directed through a series of lenses through the sample. Downstream of the sample, the light passes through another monochromator and to a photomultiplier tube (Oriel Model 77361, 400-1100nm, 800nm Peak Wavelength). The signal is amplified with a transampedence amplifier (Newport 70723, DC-300 MHz, 30 dB gain) and captured on a digital oscilloscope (Tectronix) for transfer to data storage and analysis.
