Accessing values stored in Querystring - Getting whole word rather than each letter?

Hi there,
I have a querystring like this:
d=ART-Arts_Arts&d=ART-Design_Design I am trying to loop through the values, split on the "_" symbol (the part of the value before the "_" is for internal use, and the part after the "_" is friendly text used for displaying info to the user).  If I try to do this, it seems to loop through every letter like A, r, t instead of the whole word like Art.
So, this code:
If Request.QueryString("d") <> "" Then sql = sql & " AND (" For Each Item In Request.QueryString("d") sql = sql & " tbl_OutlookCategories.DisciplineID LIKE '" & Split(Item, "_")(0) & "'" If z < Request.QueryString("d").Count Then sql = sql & " OR " Else sql = sql & " ) " End If ...