An ideal marker of human presence should be omnipresent , volatile, relatively non-reactive and continuously emitted at rela-tively high concentrations in the proximity of
an entrapped victim. Analytical possibilities with respect to the field identification of such a bio-marker are also of utmost importance. Thus,it sphysico-chemical character istics should allow for its detection by miniature, easy-to-use, low-power, fast, however, sensitive instruments