206 

 against specific classes or components. Recent experiments comparing the collection 



of extracts with isopropyl alcohol from the fingers of adults and children were 



reported in the literature [102]. This method of collection was reported to provide 



more material than extraction of fingerprints from glass; however, the time delay 



regarding collection of prints from glass was not reported. Sampling from glass, as 



was done in this work, provides a discriminating benefit with respect to attractant 



analysis. It is known that attractive emanations will be transferred to glass, and from 



observed mosquito attraction to glass, these compounds will evaporate providing a 



directional attraction of mosquitoes to the glass surface. The use of glass beads 



allows for preferential concentration of oily/waxy material over that of aqueous 



perspiration. The work contained in Chapter 3 demonstrated the low amounts of 



components present in the aqueous phase of perspiration. 



Desorption from multiple beads (in this method) involves heating these beads 



in a GC injection port. Three handled glass beads (2.9 mm diameter) provided 



enough sample to detect readily carboxylic acids, as well as many components of 



lower abundance in the sample. The use of five or more beads has saturated the ion 



source upon the elution of acids. The GC injection port provides a closed chamber 



for volatile samples to expand whether samples are injected or introduced as 



described in this work. The injection port is designed to rapidly move components 



onto the column via a carrier gas. The major difference between sampling beads in 



an injection port and in an olfactometer is the rapid heating of the beads in the GC 



