Help Needed in Regular Expression validation

Hi, 
i am working in asp.net 4.5 and i am working on registration page. i have email field on my page i am using below regex for check email validation.
<asp:TextBox ID="txtEmailAddress" runat="server" ValidationGroup="Registration" autocomplete="off" /> <asp:RequiredFieldValidator ID="reqfvUsername" runat="server" ControlToValidate="txtEmailAddress" ErrorMessage="Field Required" Display="Dynamic" ValidationGroup="Registration" ForeColor="Red"> <asp:RegularExpressionValidator ID="regexEmailAddress" runat="server" ValidationGroup="Registration" ForeColor="Red" ErrorMessage="Invalid email address" ControlToValidate="txtEmailAddress" ...