An element for the attachment of protein arrays, the element comprising a surface to which are attached a plurality of piperazine functional groups wherein the piperazine functional groups are represented by Formula I: where R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, are hydrogen, alkyl, alkenyl, alkynyl, alkylhalo, cycloalkyl, cycloalkenyl, alkylthio, alkoxy, with the proviso that at least one of R1 to R10 be a non-labile chemical unit that attaches the piperazine functional group to the surface of the element.