The extended comparison using various chain lengths of the "most oxidizable" n:3 FTCAs showed the dominance of n-2 PFCA in the products from HO• oxidation (Table , zone J). Elevating the S2O8 2-doses did not significantly alter the PFCA product distribution (Table , zones F and H) because HO• does not degrade any PFCA. In comparison, SO4 -• oxidation using the low dose of [S2O8 2-]:[n:3 FTCA]=10:1 yielded the most dominant product as n-1 PFCA. Elevating the S2O8 2-doses shifted the product distribution to short-chain PFCAs (Table , zones G). However, due to the limited capability of SO4 -• oxidation, even with a large excess of S2O8 2-at 100:1, all PFCA products were still detected after oxidative digestion, leaving various evidence for "forensic analysis" of the parent structures.