diff --git a/includes/DrupalOAuthClient.inc b/includes/DrupalOAuthClient.inc
index d0a6ee2..9b30509 100644
--- a/includes/DrupalOAuthClient.inc
+++ b/includes/DrupalOAuthClient.inc
@@ -314,7 +314,7 @@ class DrupalOAuthClient {
       }
     }
     if (!empty($params)) {
-      $url .= '?' . http_build_query($params);
+      $url .= '?' . http_build_query($params, NULL, '&');
     }
 
     $headers = array(