Document - FAVV

Evaluation of immunoassay kits for determination of ochratoxin A in cereals4.5.5 Blank sample analysisTable 69: Detection limit for three matricesWheat Winter Barley OatsN 3 3 3Degrees freedom 2 2 2t (95%) 4.13 4.13 4.13SD 0.503 0.095 2.495Q1 1.199 0.157 8.643Q3 1.284 0.200 11.376Mean (ng/g) 1.472 0.185 9.662∆xmin (ng/g) 2.546 0.481 12.620Detection limit (ng/g) 4.019 0.666 22.282The results of three blank materials are summarized in (Table 69). The kit gives good results for winter barley, forwheat the detection limit is close to the legal limit leading to a risk of false positives. The kit is clearly unable to copewith oats as a matrix confirming our findings in 0.4.5.6 ConclusionsCross reactivity with OTB was relatively high. The kit seems unable to cope with the oats we used. Also for onereference material it generated a very elevated response. The use of a phosphoric acid/dichloromethane extractionyielded the cleanest (based on visual observation) but was also the most time-consuming. With one sample we alsoobserved the formation of an emulsion.4-62 Experimental evaluation | CODA-CERVA