Submitted to: Analytical Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/23/1999
Publication Date: N/A
Interpretive Summary: Recent research into human skin emanations conducted by scientists at the USDA-ARS, Center for Medical, Agricultural, and Veterinary Entomology in Gainesville, FL, in collaboration with scientists from the University of Florida, has enabled the identification of many compounds given off by humans. Chemicals produced by the human body are attractive to blood-sucking insects, such as mosquitoes. Isolation and identification of these attractant chemicals is necessary if they are to be adopted for use in new, environmentally- safe systems for the detection and control of blood-sucking flies, such as the yellow fever mosquito, Aedes aegypti. It has been shown that the residuum on glass handled by humans will attract mosquitoes. A method involving the mass spectrometric analysis of handled glass beads resulted in the identification of over 300 compounds. These compounds thermally desorbed from glass are candidate compounds for future attractant tests involving mosquitoes and other blood-sucking insects. The primary users of this technology will be researchers interested in examining hosts for attractants, where a chemical sampling method is necessary to minimize the collection of water. Additionally, those concerned with surveillance and detection of blood-sucking flies will find this information of interest and useful.
Technical Abstract: Volatile compounds emanated from human skin were studied by gas chromatography/mass spectrometry (GC/MS). The purpose of this study was to identify compounds that may be human-produced kairomones which are used for host-location by the mosquito, Aedes aegypti (L.). The procedure used to collect volatiles was chosen because of prior knowledge that attractive substances can be transferred from skin to glass by handling. Laboratory bioassays have shown that the residuum on the glass remains attractive to mosquitoes until the compounds of importance evaporate. The sampling and analytical procedures modeled the above cited process as closely as possible except that the evaporation of compounds from the glass surface was accomplished by thermal desorption from glass beads in a heated GC injection port. This made possible the solventless injection of volatiles onto the column. The compounds were cryofocused on the head of the column with liquid nitrogen prior to GC separation. A single stage of mass spectrometry on a triple quadrupole instrument was used for mass analysis. A combination of electron ionization and pulsed positive ion negative ion chemical ionization modes on two different GC columns (one polar, one relatively non-polar) was used to identify tentatively most of the 346 compound peaks detected by this technique.