this is how I have done this in .Net using LinqToTwitter
var twitterCtx = new TwitterContext(authTwitter);
var verifyResponse =
await
(from acct in twitterCtx.Account
where (acct.Type == AccountType.VerifyCredentials) && (acct.IncludeEmail == true)
select acct)
.SingleOrDefaultAsync();
if (verifyResponse != null && verifyResponse.User != null)
{
User twitterUser = verifyResponse.User;
//assign email to existing authentication object
loginInfo.Email = twitterUser.Email;
}