Application of manual and automated systems for purification of ochratoxin A and zearalenone in cereals with immunoaffinity columns

A manual vacuum manifold and an automated solid phase extraction (ASPEC) system were applied for purification of ochratoxin A and zearalenone in wheat, rye, barley, and oat samples with immunoaffinity columns followed by separation with a high-performance liquid chromatograph and fluorescence detection. The immunoaffinity columns for manual sample purification were purchased from a different manufacturer than were those for the automated system. The limit of detection (LOD) for the method for ochratoxin A with a vacuum manifold and ASPEC was 0.1 mug/kg. For the method for zearalenone, the LODs were 1.5 mug/kg with a vacuum manifold and 3 mug/kg with ASPEC. For the methods for ochratoxin A at spiking levels of 0.6 and 2.5 mug/kg, mean recoveries for different cereals varied from 68 to 106%. For the methods for zearalenone, mean recoveries varied from 78 to 117% at spiking levels of 9 and 25 mug/kg. The relative standard deviations of repeatability with various cereals employing both methods were 2-15 and 2-19% for ochratoxin A and zearalenone, respectively.