J.
Aldstadt, J. Ammerman, Dept. of Chemistry
Project
Summary:
We are developing methods with high sensitivity
and selectivity for continuous on-line measurement
of toxic substances in drinking waters.
Sample Preparation System
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Our
efforts are directed at improved sample preparation
techniques based on solid-phase extraction (SPE)
for the sampling, extraction, preconcentration,
and matrix removal of biotoxins in drinking water.
These methods will support the compilation of a
database for 'exotic' agents in aqueous samples.
We use liquid chromatography coupled to electrospray
ionization mass spectrometry (LC-ESI-MS) for quantitation.
By variation of the ionization and mass analysis
conditions, optimized ESI-MS methods are
Reversed-Phase Liquid Chromatography-
Electrospray Ionization Mass Spectrometry
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written
that will permit a wide range of peptides to be
measured. To simulate toxins such as microcystins
(cyclic heptapeptide hepatotoxins produced by cyanobacteria)
and ricins (large dimeric proteins produced by
castor beans), we use tryptic digests of globular
proteins (e.g., serum albumin, myoglobin) to produce
complex mixtures that provide a wide range of polypeptides
for analysis. A flow-injection based approach has
been designed using ion-exchange or partition extraction
resins so that a wide range of possible toxins
can be efficiently sampled. We are also designing
a novel SPE separation approach using a polymer-based
monolithic stationary phase.
Mass Spectrum of Myoglobin
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