Anew method describing direct attachment of carboxylated haptens on a polystyrene support, using 3-aminopropyltriethoxysilane (3-APTES) as a linker, is reported. The hapten coated polystyrene support showed excellent stability as a function of the buffer pH and reaction time, and was successfully used to demonstrate its application in enzyme-linked immunosorbent assay (ELISA). (C) 2003 Elsevier B.V. All rights reserved.