An affinity ligand-matrix conjugate comprising a ligand of general formula: wherein: m represents 0 or 1; n represents 2 or 3; p represents 0, 1, or 2; R 1 represents hydrogen; and each R 2, when present, may be selected independently from carboxyl, cyano, halogen, hydroxy, nitro, phosphono, phosphorylamino, phosphinyl, sulfo, trihalomethanethio, optionally substituted acyl, optionally substituted acylamino, optionally substituted acylimino, optionally substituted acyliminoxy, optionally substituted acyloxy, optionally substituted arylalkyl, optionally substituted arylalkoxy, optionally substituted alkenyl, optionally substituted alkenyloxy, optionally substituted alkoxy, optionally substituted alkyl, optionally substituted alkynyl, optionally substituted alkynyloxy, optionally substituted amino, optionally substituted aminoacyl, optionally substituted aminoacyloxy, optionally substituted aminosulfonyl, optionally substituted aminothioacyl, optionally substituted aryl, optionally substituted arylamino, optionally substituted aryloxy, optionally substituted cycloalkenyl, optionally substituted cycloalkyl, optionally substituted heteroaryl, optionally substituted heterocyclyl, optionally substituted oxyacyl, optionally substituted oxyacylamino, optionally substituted oxyacyloxy, optionally substituted oxyacylimino, optionally substituted oxysulfinylamino, optionally substituted oxysulfonylamino, optionally substituted oxythioacyl, optionally substituted oxythioacyloxy, optionally substituted sulfinyl, optionally substituted sulfinylamino, optionally substituted sulfonyl, optionally substituted sulphonylamino, optionally substituted thio, optionally substituted thioacyl, and optionally substituted thioacylamino, or any two adjacent R 2 may together form an optionally substituted aryl, optionally substituted heteroaryl, or optionally substituted heterocyclyl and said ligand is immobilised onto a support matrix in position, optionally through a linker group interposed between the matrix and ligand. m represents 0 or 1; n represents 2 or 3; p represents 0, 1, or 2; R 1 represents hydrogen; and each R 2, when present, may be selected independently from carboxyl, cyano, halogen, hydroxy, nitro, phosphono, phosphorylamino, phosphinyl, sulfo, trihalomethanethio, optionally substituted acyl, optionally substituted acylamino, optionally substituted acylimino, optionally substituted acyliminoxy, optionally substituted acyloxy, optionally substituted arylalkyl, optionally substituted arylalkoxy, optionally substituted alkenyl, optionally substituted alkenyloxy, optionally substituted alkoxy, optionally substituted alkyl, optionally substituted alkynyl, optionally substituted alkynyloxy, optionally substituted amino, optionally substituted aminoacyl, optionally substituted aminoacyloxy, optionally substituted aminosulfonyl, optionally substituted aminothioacyl, optionally substituted aryl, optionally substituted arylamino, optionally substituted aryloxy, optionally substituted cycloalkenyl, optionally substituted cycloalkyl, optionally substituted heteroaryl, optionally substituted heterocyclyl, optionally substituted oxyacyl, optionally substituted oxyacylamino, optionally substituted oxyacyloxy, optionally substituted oxyacylimino, optionally substituted oxysulfinylamino, optionally substituted oxysulfonylamino, optionally substituted oxythioacyl, optionally substituted oxythioacyloxy, optionally substituted sulfinyl, optionally substituted sulfinylamino, optionally substituted sulfonyl, optionally substituted sulphonylamino, optionally substituted thio, optionally substituted thioacyl, and optionally substituted thioacylamino, or any two adjacent R 2 may together form an optionally substituted aryl, optionally substituted heteroaryl, or optionally substituted heterocyclyl and said ligand is immobilised onto a support matrix in position, optionally through a linker group interposed between the matrix and ligand.