New microsensor measures volatile organic compounds in water and a...(ameter of approximately 200-300 microns ...)

To determine how to selectively detect multiple pollutants in the same sample, Brand began collaborating with Boris Mizaikoff, an associate professor in Georgia Techs School of Chemistry and Biochemistry and director of its Applied Sensors Laboratory.

Mizaikoff and graduate students Gary Dobbs and Yuliya Luzinova selected commercially available hydrophobic polymers and deposited them as thin film membranes on the sensor surface. They continue to investigate innovative ways to consistently deposit the polymers at the disk surface, while ensuring sufficient adhesion for long-term field applications.

By modifying the silicon transducer surface with different polymer membranes, each sensor becomes selective for groups of chemicals, explained Mizaikoff.

An array of these sensors, each sensor with a different chemically modified transducer surface, can sense different pollutants in a variety of environments ranging from industrial to environmental and biomedical monitoring applications.

Brand and Mizaikoff aim to detect volatile organic compounds (VOCs) in aqueous and gaseous environments. VOCs are pollutants of high prevalence in the air and surface and ground waters. They are emitted from products such as paints, cleaning supplies, pesticides, building materials and furnishings, office equipment and craft materials.

A common VOC is benzene, with a maximum contaminant level set by the Environmental Protection Agency (EPA) at five micrograms per liter in drinking water. Many VOCs are present at similar very low concentrations, so effective sensors must accurately measure and discriminate very small mass changes.

Weve been able to measure concentrations among the lowest levels that have been achieved using this type of resonant microsensor, noted Brand. While w
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