Thanks, but after looking on the endless web I put together this.
Code:
For Each rcell In Range("L4:L150")
If rcell.Value Like "?*@?*.?*" Then
next_cell_value = next_cell_value & "; " & rcell
If InStr(next_cell_value, rcell) = 0 Then next_cell_value = next_cell_value & rcell & ";"
End If
Next rcell