open (FILE, '<', 'prev.txt') or die "Can't open prev.txt\n";

while (<FILE>) {
   my @email = (split('\s',$_))[1..3];

   for (@email) {
       # send email
       # log results
   }
}

##</code><code>##

use Email::Valid;

open (FILE, '<', 'prev.txt') or die "Can't open prev.txt\n";

while (<FILE>) {
   my @stuff = split;

   for (@stuff) {
      next unless Email::Valid->address($_);
      # send email to $_
      # log results
   }
}