http://insciences.org/article.php?article_id=8507

ASU scientist N.J. Tao and his colleagues at the Biodesign Institute have hit on a new, versatile method to significantly improve the detection of trace chemicals important in such areas as national security, human health and the environment.

Tao's team was able to detect and identify tiny particles of the explosive trinitrotoluene or TNT – each weighing less than a billionth of a gram – on the ridges and canals of a fingerprint.

"We can easily detect the TNT traces because we combine the strength of optical microscopy, which gives spatial resolution, with the high sensitivity and selectivity of electrochemical detection," he said. Results of this research appear in the March 12 issue of Science.

Tao's work involves the application of a hybrid technique – called electrochemical imaging microscopy – developed in his lab.

"We don't use electrochemistry alone," said Tao, director of Biodesign's Center for Bioelectronics and Biosensors and electrical engineering professor in the Ira A. Fulton Schools of Engineering. "We combine electrochemical sensing with other techniques, including optical detection."