Solid-phase extraction of ochratoxin A from wine based on a binding hexapeptide prepared by combinatorial synthesis

In this paper we describe the preparation of a hexapeptide library by combinatorial synthesis and the identification of a peptide with sequence Ser-Asn-Leu-His-Pro-Lys, which showed good affinity (Keq = 3.4×104M−1) towards the mycotoxin ochratoxin A (OTA). An immunoaffinity-like stationary phase supporting such a hexapeptide was used to develop a solid-phase extraction method for the quantification of OTA in wine samples at concentration levels down to 0.10 mug/l. Several different wine samples fortified with OTA at 2 and 4 mug/l levels showed recovery of 94.7% and 98.4% at 2.0 and 4.0 mug/l, respectively, without any effect on the extraction efficiency of the matrix. The efficacy of this approach was successfully tested by comparison with an immunoaffinity extraction performed on commercial cartridges