mail id validation

using System.Text; 

private bool IsValidEmail(string email)        
{            
    string emailRegEx = @"^[a-z][a-z|0-9|]*([_][a-z|0-9]+)*([.][a-z|"
                      + @"0-9]+([_][a-z|0-9]+)*)?@[a-z][a-z|0-9|]*([-][a-z|0-9]+)*\.([a-z]" 
                      + @"[a-z|0-9]*(\.[a-z][a-z|0-9]*)?)$";
    RegularExpressions.Match match = 
    RegularExpressions.Regex.Match(email, emailRegEx, RegularExpressions.RegexOptions.IgnoreCase);            
    return match.Success;  
}