207 

 injection port rather than evaporation at ambient temperature in the olfactometer 



port. 



In the initial stages of this project, the separation process employed relatively 

 short column lengths (approximately 15 m). The stationary phases ranged from a 

 highly nonpolar column (DB-5) to a polar column (Carbowax). The abundant acids 

 in the sample were better chromatographed on the Carbowax column, i.e. the peak 

 profiles were more Gaussian. The limitations of these analyses were two-fold. 

 Although the 15 m columns did provide better separation than previously seen from 

 simple thermal desorption, even better separation was desired. This required the use 

 of longer columns to increase the number of theoretical plates. The second problem 

 involved the instability of the Carbowax column at high temperatures. The stationary 

 phase of the carbowax column is not stable at temperatures above 220°C. Analyses 

 routinely involved approaching or holding the column at this temperature. These 

 problems were rectified by employing longer columns (25 m) and using an HP-FFAP 

 FSOT column in place of the Carbowax column. The maximum temperature of the 

 HF-FFAP column is listed at 240°C. 



The rapid heating of the beads with subsequent loading of volatilized 

 components onto a column does not provide adequate temporal resolution for 

 identification of compounds present. Therefore, cryo-focusing or microscale purge 

 and trap was used prior to separation on the column. 



