$re = '/\\\\\"([^\"]{27})\\\\\"/m';
$str = ' \'[[\\"jewelry_designer\\"]\\n,[\\"watch_store\\"]\\n,[\\"jewelry_appraiser\\"]\\n,[\\"leather_goods_store\\"]\\n]\\n,null,\\"DpIJr_dR-DNu5kcR9RGmRprcnGU\\",null,null,null,[null]\'';
preg_match_all($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