I'd personally use regexp method that GrandFather suggests because it gives me just the data I'm after with the added benefit of (basic) sanity checks, but if you're going to go the split method, using a more complex pattern avoids the need for post-split massaging...
my @result = split /(: |.<|>,)/;
my($qid,$email,$status) = @result[2,6,10];
my($qid,$email,$status) = (split /(: |.<|>,)/)[2,6,10];
And depending on the extent of your Postfix-log parsing needs, you may be able to save yourself some effort by using or bastardizing pflogsum (assuming you don't find the code too hairy :-)).