@cols = ( "foo", "\t", "bar" );
print "original '@cols' ", scalar @cols, "\n";

s/\t/<%tab%>/g for @cols;
$row = join "\t", @cols;
print "row      '$row'\n";

@ret_cols = split "\t", $row;
s/<%tab%>/\t/g for @ret_cols;

print "retreive '@ret_cols' ", scalar @ret_cols, "\n";

__DATA__
original 'foo 	 bar' 3
row      'foo	<%tab%>	bar'
retreive 'foo 	 bar' 3