You can use this snippet to parse an email address and extract the different components of it. (Tip. It works for UPNs too)

New-Object "System.Net.Mail.MailAddress" -ArgumentList $emailAddress
Details
You can also send strings formatted with the display name. For example:

‘Microsoft Azure <[email protected]>’


Example
PS C:\> $emailAddress = '[email protected]'
>> New-Object "System.Net.Mail.MailAddress" -ArgumentList $emailAddress


DisplayName User       Host        Address
----------- ----       ----        -------
            mick.jones contoso.com [email protected]