324 

 CI, and ultimately must be fonned from reactions of hexadecanoic acid with 

 fragments of itself. 



Summary 



The use of ECNCI with CO2 is potentially an asset for continued work 

 involving the identification of trace levels of skin emanations. The fundamentals of 

 using CO2 as a reagent gas, as well as the problems encountered during preliminary 

 experiments, have been covered herein. Reducing impurities is a necessary step to 

 successful use of this reagent gas. Purification and cold-trapping of CO, gas prior 

 to introduction in the ion source may be necessary to reduce or eliminate water. 

 Prolonged pretreatment of the ion source with COj prior to analysis would also be 

 beneficial for the reduction of surface bound radicals. Finally, reduction of sample 

 size would eliminate self-CI reactions due to saturated conditions. The proposed 

 avenue for this is the use of a purge and trap system similar to that used for studies 

 in Chapter 5. This would remove water and acids, which dominate the analyses, 

 leaving trace components to be readily identified. With these suggestions, the 

 technique of COj/ECNCI may provide information not previously accessible. 



