## 3 Results and Discussion
### Screening Analysis (ELISA) Results
#### 3.1.2 Precision and Recovery  
Since the screening procedure may also be used as quantitative method, precision tests were performed. The validation of the kit allowed for the determination of the concentration of the sum of the T-2 and HT-2 toxins in the range between 75 and 900 \(\upmu\) kg\({}^{-1}\). Precision was calculated either in terms of repeatability (or within-laboratory reproducibility) and reproducibility (or between-laboratory reproducibility). These analyses were carried out  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Sample**} & \multicolumn{6}{c}{**First Analytical Session**} & \multicolumn{6}{c}{**Second Analytical Session**} \\ \cline{2-9}  & \multirow{2}{*}{**Matrix**} & **B/B\({}_{0}\) (\%)** & **B/B\({}_{0}\) (\%)** & **Spiked Samples** & **Confentation** & **B/B\({}_{0}\) (\%)** & **B/B\({}_{0}\)** (\%)** & **Spiked Samples** \\  & & **Blank** & **Spiked** & **Confentation** & **Blank** & **Spiked** & **Confentation** \\  & & **Sample** & **Sample** & **(\(\upmu\) kg\({}^{-1}\))** & & **Sample** & **Sample** & **(\(\upmu\) kg\({}^{-1}\))** \\ \hline
1 & Wheat & 0.75 & 0.30 & 261.3 & 11 & Wheat & 0.75 & 0.30 & 261.3 \\ \hline
2 & Wheat & 0.75 & 0.34 & 218.0 & 12 & Wheat & 0.81 & 0.35 & 212.8 \\ \hline
3 & Maize & 0.78 & 0.31 & 249.0 & 13 & Maize & 0.79 & 0.31 & 248.5 \\ \hline
4 & Maize & 0.62 & 0.30 & 261.5 & 14 & Maize & 0.62 & 0.30 & 261.8 \\ \hline
5 & Composed feed & 0.63 & 0.28 & 298.0 & 15 & Comp. feed & 0.63 & 0.26 & 323.0 \\ \hline
6 & Composed feed & 0.65 & 0.31 & 253.5 & 16 & Comp. feed & 0.65 & 0.32 & 249.0 \\ \hline
7 & Barley & 0.77 & 0.30 & 263.5 & 17 & Barley & 0.77 & 0.30 & 262.5 \\ \hline
8 & Barley & 0.67 & 0.33 & 230.3 & 18 & Barley & 0.67 & 0.34 & 222.3 \\ \hline
9 & Oat & 0.65 & 0.29 & 285.0 & 19 & Oat & 0.65 & 0.26 & 346.8 \\ \hline
10 & Oat & 0.62 & 0.29 & 280.5 & 20 & Oat & 0.63 & 0.26 & 340.0 \\ \hline  & Average & 0.69 & 0.30 & 260.1 & Average & 0.70 & 0.30 & 272.8 \\ \hline  & SD & 0.0655 & 0.0184 & & SD & 0.0742 & 0.0324 \\ \hline \hline \end{tabular} SD: standard deviation.  
\end{table}
Table 2: Selectivity tests of ELISA validation. Results obtained by analyzing 20 cereal blank samples and samples spiked with 250 \(\upmu\) kg\({}^{-1}\) of the HT-2 toxin.  
on two sets of blank feed samples (a mix of composed feed and raw materials) fortified at two different concentrations of the T-2 and HT-2 toxins (100 and 250 ug kg\({}^{-1}\)) using the T-2/HT-2 standard solution. Good performances were obtained in terms of the coefficient of variation (CV; %) under repeatability conditions (6.5%). As reported in the European Commission Decision No. 657/2002, this parameter has to be lower than 23% and 16% for the fortification levels equal to 100 and 250 ug kg\({}^{-1}\), respectively. This parameter was comparable with the precision of ELISA obtained by [PERSON] et al. [21], who analyzed the same types of cereals samples investigated in the present study, and higher that that reported by [PERSON] et al. [22] for rye and baby porridge analysis. The recovery percentage was satisfactory as well, since both fortification levels gave a mean value of 102%, whereas the required range set in Decision No. 657/2002 is 80-110%.