You can validate email using the following objective c code-

-(BOOL)isValidEmail:(NSString *)emailString
{
NSString *filterString = @"^[A-Z0-9a-z\\._%+-]+@([A-Za-z0-9-]+\\.)+[A-Za-z]{2,4}$";
NSPredicate *emailPredicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", filterString];
return [emailPredicate evaluateWithObject:emailString];
}