Comparison of two different immunoafinity columns for the extraction and clean-up of ochratoxin A in must

PONSONE, L; TORRES, A.M.; COMBINA, M.; DALCERO, A.M; CHULZE, S.N

Estambul-Turquia

Simposio; XII International IUPAC Symposium on Mycotoxins and Phycotoxins; 2007

IUPAC

  Ochratoxin A (OTA) is produced by Aspergillus section Nigri in grapes. This mycotoxin is associated to nephropathy in humans, and may have a long half-life in human blood. One of the source of OTA for humans is wine. Most of analitical methods developed for OTA in wine, beer and other products are based on LC with fluorescence detection (LC-FLD). The aim of this study was to compare two procedures of extraction and cleanup for OTA determination in must. The must was spiked with 3 OTA levels: 2, 5 y 10 ìg/L. (1) Must dilution with polyethylenglicol 8000 and Na2CO3 solution clean-up on commercial immunoaffinity column A. (2) Dilution with phosphate buffer and clean-up on commercial immunoaffinity column B. The toxin was determined by HPLC system, equipped with a fluorescence detector (excitation, 330 nm; emission, 460 nm) and a LunaTM C18 column (150 x 4.6 mm, 5 ìm particle size); connected to a guard column Security GuardTM filled with the same phase (20 x 4.6 mm, 5 ìm particle size). The mobile phase (57% acetonitrile, 41% water and 2% acetic acid) was pumped at 1.0 ml min-1. OTA was quantified on the basis of HPLC fluorometric response compared with OTA standard (purity > 99%; Sigma Aldrich Co). The detection limit was 0.01 ng ml-1. Recovery was better using columns A (average 107%) in comparison with columns B, average recovery 44 % of the OTA spiked.