Analysis: S/G ratios were calculated using the S4-8 and G4-8 peak areas. The ratios (Ad/Al)S,G were calculated using the peak areas of S6 and S4, G6 and G4 respectively. Table gives the structures, chemical names, and characteristic ions of the compounds used. At least four different aliquots of each sample or subsample were taken to provide an average and standard deviation for each value.