278 

 compounds originate from humans or may are deposited on the skin by external 

 sources. The final compound to be addressed from this table is 3-(l-methyl-2- 

 pyrrolidinyl)pyridine (nicotine). This compound was found in much greater 

 abundance on the skin for subjects who use tobacco products. 



Case Study Comparison of Bio-assay to GC/MS Assay 



The final study of this chapter involves the analysis of emanations from a 

 single host, collected once per day for GC/MS and bio-assay, over a five-day period. 

 The advantage to this comparison is thought to be that a single host provides a more 

 stable and consistent matrix on the skin, with less chance of markedly different trace 

 emanations. The drawback is that the subject variation in attraction to mosquitoes 

 will not vary as much as it would for persons chosen at the extremes of attraction (as 

 in the previous case study). 



The range of attraction in the olfactometer, for the five-day period, fell 

 between 12 and 27%. The actual comparison employed only the first two days. The 

 RIC traces from samples analyzed on these two days are shown in Figure 5-3. The 

 results from these analyses are reported in table 5-5. The remark codes used in this 

 table are identical to those for table 5-4. 



The two compounds of interest from this table are the unsaturated alcohols 

 identified as 4-hexen-l-ol and l-hepten-3-ol. Both of these compounds were present 

 at increased relative abundance on the day the human subject was more attractive 



