verify email address - find invalid characters

our asia pacific region something entered email address with characters that is not acceptable by SMTP protocol, eg:

abc@abc.co.ＪＰ

(the character  jp were entered as ＪＰ)

we would like to write a plsql code to screen all single chars of the email address in a column table to find characters which has ascii < 32 or ascii>126

we have a function call hasWrongChar(p_email_address varchar2) to do a looping checking each single character if the ascii < 32, or ascii>126.

we try to test by calling:

haswrongchar( chr(200)||'asc')  - and the function return N (after checking, we found that chr(200) is not appended as the length function return 3)