Perspiration has crime-busting potential, according to Israeli chemists who say that the food we eat, drugs we take, gender and even state of mind, all combine to make each person's sweat unique. Dr. Michael Gozin of Tel Aviv University's School of Chemistry is trying to revolutionize the field of "sweat science." He and his team are looking at the biochemical components of human sweat as a new kind of ID, positing that each person has his or her very own chemical fingerprint. "Dogs and other animals can differentiate between people easily, defining each person by his or her smell. Some animals can track us wherever we go," says Gozin, whose lab is preparing to work on this project with the US Air Force. "All people sweat, so we thought: Why not try and track it?" Now working on isolating various biochemical components of sweat, Gozin hopes to present the first paper of the findings in this unique field of research later this year. Perspiration and perpetrators Sweat is a complex mixture of proteins and byproducts of our metabolism emitted from our pores. It also contains volatile compounds, only some of which our noses pick up. Gozin is investigating those compounds with heavy molecular weights, like proteins and peptides, which stick around long after a person and his or her smell have vanished. If Gozin's thesis proves true, sweat could be used to track terrorists and criminals when fingerprints are partially damaged or do not exist. By analyzing the chemical composition of sweat collected from garments or surfaces, suspects could be traced and found. "These heavier molecules will stay on the skin or the surface of a table if you touch it. We are figuring out in what proportions these compounds are found in the sweat of individuals," says Gozin. He surmises that there are thousands of different chemical compounds in our sweat, some in only very minute trace amounts. Some compounds, Gozin expects, will be found in comparable proportions among all humans, but like a fingerprint, or DNA, the ratio among other compounds in any given individual may be unique. Smell the difference Besides crime fighting, defense and security applications, the chemical ID could be used to track and trace missing children, or by doctors to help understand human maladies. Using a high-end mass spectrophotometer provided by the US Department of Defense and Israeli Ministry of Defense, Gozin expects that results from sweat tests can be produced in real-time, much more quickly than today's or even tomorrow's DNA tests. In theory, sweat ID could be used in conjunction with a so-called "bionic nose," a sensor that "sniffs" people at locations such as security checkpoints. Stressing that this basic research is in its early stages, Gozin said that the first indication of success will be the ability of his system to distinguish between male and female sweat.