47 

 was methane at 1650 mtorr and 1660 mtorr (indicated) pressures, respectively. The 



ion source and manifold temperatures were 150°C and 70°C, respectively, for CI and 



170°C and 70°C, respectively, for EI. The electron energy for CI experiments was 



100 eV and for EI, 70 eV. The third quadrupole (Q3) was scanned with a scan time 



of 2 s for figures in this section. The filament emission current was set at 200 jiA. 



The conversion dynode was set at +5 kV for positive ion CI and EI, and -5 kV for 



negative ion CI. Tlie electron multiplier was set at -1000 V to -1200 V. Prior to 



analysis the instrument was tuned with PFTBA as previously mentioned and blanks 



(appropriate number of beads without sample) were analyzed. 



Purge and Trap/GC Separation 



Some analyses were performed using a microscale purge & trap system. Tlie 

 sampling difference between figures shown in this section of the chapter was the 

 method of collection of skin emanations. Some experiments involved handling 200- 

 250 glass beads 10 min. The beads were then transferred to the same 100 mL round 

 bottom flask discussed previously. The round bottom flask was attached to the purge 

 and trap system via a 1/2" Cajon fitting to 1/4" Swagelok, further reduced to a 1/8" 

 Swagelok fitting. Skin emanations were also sampled by placing the left hand in a 

 Tedlar bag and fastening the bag around the wrist with a rubber band. The Tedlar 

 bag was attached to the purge and trap system by a 1/8" Swagelok fitting. The flask 

 or bag was attached to a port on an ELA2010 canister manifold (Entech Laboratory 

 Automation). 



