Ochratoxins determination in beers by direct injection of the sample using a IS-anionic column chromatography

Abstract

Ochratoxin A is nephrotoxic and has been found in corn, soy, wheat, barley, rice, sorghum and peanut samples. Brazilians consume in average 49 liters of beer yearly, barley being the main raw material, besides maize and rice in a second level. The determination of the ochratoxins A and B in alcoholic beverages require clean-up or immunoaffinity columns. A new analytical method by direct injection of the sample of beer, using liquid chromatography of high efficiency, with a IS-anionic chromatographic column (Internal Surface Reverse Phase) was developed. The considered method presented a recovery that varied from 78.5 to 92.1% for the levels of ochratoxin A in the range of 0.25 to 4.00µg.L-1; and 76.5 to 93.1% for the ochratoxin B at the level of 1.25 to 20.00µg.L-1. The limits of detection were 0.15 and 0.35µg.L-1 and the limits of quantification 0.25 and 0.60µg.L-1 for ochratoxins A and B, respectively. In a total of 42 samples of beers commercialized in Bauru and region, 2.4% of the samples of national beers and 11,1% of the imported ones were contaminated with ochratoxin A above the of quantification, being the level detected between 0.32 and 0.80µg.L-1. ochratoxin B was detected in only 2.4% of national beer samples at the level of 0.78µg.L-1.