Document - FAVV

Evaluation of immunoassay kits for determination of ochratoxin A in cereals4.3 RIDASCREEN® Ochratoxin A 30/15 by R-Biopharm4.3.1 Concentration accuracy of standardsThe kit of R-Biopharm is supplied with 6 ready to use standard solutions with a concentration ranging from 0(blank) to 1.8 ng/ml OTA, corresponding to a concentration of 0 to 36 ng OTA per gram cereal. The results,summarized in Table 49, don‟t highlight any anomalies in the standards.Table 49: Accuracy of calibrantsCalibrant (ng/g) LC-MS/MS (ng/g) % Dev T-Test0 0.000 / 0.892260.05 0.069 380.1 0.126 260.3 0.383 280.9 1.073 191.8 1.846 34.3.2 Cross-reactivity4.3.2.1 SolventThe cross-reactivity was checked on five different concentrations, corresponding to the concentration of thestandards. 0.13 M NaHCO 3 in deionised water was used as extraction solvent. From Table 50 and Figure 12 it is clearthat no component (other than OTA) shows significant cross-reactivity. Only for OTB and OTα there was someslight cross-reactivity, only visible at very high concentration. For the other components the IC 50 was virtually nonexisting.Table 50: Cross-reactivity in solventOTA OTB Otα CIT ZEA AFLA B1 COU 4-HC PheSlope -1.0454 -0.4909 -0.5535 0.2177 -0.9677 0.2592 0.1230 0.1448 -0.1356Intercept 1.1448 1.3183 1.2364 1.2022 2.8292 1.3339 1.0879 0.9117 1.1039R 2 0.9976 0.8922 0.8152 NR NR NR NR NR NRSE Slope 0.0359 0.0985 0.1522 NR NR NR NR NR NRSE Intercept 0.0389 0.0954 0.1474 NR NR NR NR NR NRIC50 (ng/g) 12.45 484.63 171.28 3,E+05 8,E+02 1,E+05 7,E+08 2,E+06 1,E+08Relative Crossreactivity 100.0% 2.6% 7.3% 0.0% 1.5% 0.0% 0.0% 0.0% 0.0%CODA-CERVA | Experimental evaluation 4-51