$re = '/(?<=@)[^:]+/';
$str = 'pop3://abby@supremefill.com:ash9675@173.201.192.199:110
pop3://abby@jsnitro.com:littleman@173.201.192.199:110
smtp://tania@heritagecentre.ca:PCHta13@69.49.109.86:25
pop3://tania@heritagecentre.ca:PCHta13@69.49.109.86:110
pop3://abby@supremefill.com:ash9675@173.201.193.199:110
pop3://abby@jsnitro.com:littleman@173.201.193.199:110
smtp://liangyuan820211:820211ly520@202.108.6.242:25
pop3://smartinez@tornadobus.com:Sophia123@64.26.60.221:110';
preg_match_all($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