$re = '/\s*((?:(?:Mr|Dr|Ms|Jr|Sr)\.|\.(?!\s+[A-Z0-9])|[^.!?])*[.?!]|[^.!?]+)/';
$str = 'Mr. Smith bought cheapsite.com for 1.5 million dollars i.e. he paid a lot for it. Did he mind? Adam Jones Jr. thinks he didn\'t. In any case, this isn\'t true... Well, with a probability of .9 it isn\'t.23 is the ish. My name is! Why wouldn\'t you... this is.
Andrew';
preg_match_all($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