$re = '/(?<=\d)\t(?=\d)|\t(?=[A-Z@<:]{14})|(?<=[A-Z@<:]{14})\t/m';
$str = 'C42TMACXX:5:2316:15161:76101 163 1 @<@DFFADDDF:DD NH:i:1 HI:i:1 AS:i:200 nM:i:0
C42TMACXX:5:2316:15161:76101 83 1 CCCCCACDDDCB@B NH:i:1 HI:i:1 nM:i:1
C42TMACXX:5:1305:26011:74469 163 1 CCCFFFFFHHHHGJ NH:i:1 HI:i:1 AS:i:200 nM:i:0';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php