testing on email characters

[charles]

    if ( $add_alias =~ /\@/ ) {

right now i am testing a variable to see if it contains an \@ character. i
would prefer to test it to see if it has anything *other* than
a-zA-Z0-9\.\-\_

can i do this with a regex like

    if ( $add_alias =~ /[^a-zA-Z0-9\.\-\_]/ ) {

i am not certain if my search range is too broad.