Pulled it out of my ass but you could try the below code.
Note that this is completely untested, if it doesn't work then you're out of luck unless I can check it on my Shammy later or someone else can fix it.
Code:
local a = CreateFrame("Frame")
a:SetScript("OnEvent", function(self, event, ...)
self.pguid = self.pguid or UnitGUID("player")
local arg = {...}
if arg[2] == "SPELL_DISPEL" and arg[10] == "Purge" and arg[3]==self.pguid then
SendChatMessage("Just Purged "..GetSpellLink(arg[12]), "EMOTE")
end
end)
a:RegisterEvent("COMBAT_LOG_EVENT_UNFILTERED")
Instructions to use: http://www.mmo-champion.com/threads/...lve-easy-steps