Purdue University researchers created the first 2D images of biological samples using a new mass spectrometry technique called desorption electrospray ionization (DESI). The work is being done to expand the technology's use in detection of diseases such as cancer. The technology measures characteristic chemical markers that distinguish diseased from nondiseased regions of tissue samples within a few seconds. DESI also eliminates the need for samples to be treated with chemicals and specially contained. "This technology could be used to aid surgeons in precisely and completely removing cancerous tissue,” said Graham Cooks, Purdue's Henry B. Hass Distinguished Professor of Analytical Chemistry, in whose lab DESI was developed. "With these images, we can see the exact location of tumor masses and can detect cancerous sites that are indistinguishable to the naked eye." Methods currently in use rely on the trained eye of a pathologist who views stained tissue slices under a microscope to assess what tissue must be removed.