176 

 with CID yielded a daughter spectrum that can be interpreted as the [M-H]~ ion of 



pyruvic acid due to the similarity of fragmentation to that of the [M-H]~ ion of lactic 



acid. 



The remainder of the compounds identified by this technique contain an 



alcohol moiety. Phenol and ethylene glycol were identified by comparison of 



daughter spectra from skin emanations to daughter spectra of [M-H]~ ions of the 



pure standards acquired under identical conditions. The presence of cholesterol was 



suspected mainly due to the presence of m/z 385 under NCI conditions, and the 



neutral loss of 18 Da from CID of the m/z 387 [M+H]"^ parent ion. 



Daughter Library 



The initial driving force behind compiling a library of daughter spectra was 

 to aid in the determination of compounds by MS/MS. The library itself is made up 

 of numerous classes of compounds, some multi-class, and some containing two or 

 more functional groups of the same class. Compilation of an extensive library for 

 work in this dissertation was not necessary due to the nature in which the library was 

 ultimately used. The information derived from the tabulated library data was used 

 to aid in rapid screening by MS/MS rather than, as originally planned, extensive 

 identification of compounds by MS/MS. 



The MS/MS trends observed for the positive and negative ion CI parent ions 

 of the compounds tested are listed in Table 4-2; some of these observations will be 

 discussed in the text following this paragraph. This table contains fragmentation and 



