## 3 Results and Discussion
### Comparison between the ELISA and UPLC/FLD Method
Regarding accuracy performance, method trueness (expressed as recovery %) was comparable, while method precision (CV%) was slightly higher for the ELISA due to the sample preparation procedure of UPLC/FLD being composed of more steps and thus having a decrease in repeatability. Other than validation parameters, the two approaches were also compared by analyzing 100 samples of cereals (20 durum wheat, 11 common wheat, 15 corn, 31 barley,and 23 oats) by using both methods. All samples were collected from a specific area located in the north-east of the Puglia region (Italy) named \"Capitanata.\" All samples of cereals were harvested in the field after reaching the optimal ripeness in the period between May and July 2018. The ELISA method allowed for the determination of the sum of T-2 and HT-2 toxins contents, with an LOD of 75 ug kg\({}^{-1}\), while the UPLC/FLD method, which was more sensitive, allowed for the determination of T-2 and HT-2 toxins with LOQs equal to 29 and 19 ug kg\({}^{-1}\), respectively. No samples with T-2 or HT-2 concentrations greater than the reference values reported in European Recommendation No. 165/2013 were verified. Sixty-six samples were not contaminated (concentration lower than quantification limit) for both the ELISA and UPLC/FLD. The results obtained by analyzing other 27 samples were substantially in accordance between two methods. These results were elaborated by using linear regression. A good correlation (\(r=0.9056\); \(n=27\)) was found (Figure 3). Seven samples were characterized by different results if analyzed through two approaches. Five samples were found to not be contaminated by using ELISA, but quantifiable amounts were detected by using the chromatographic method (in the range of 32.6-56.9 ug kg\({}^{-1}\)). In Figure 2D, a chromatogram example related to the analysis of a corn sample that was contaminated with 315.9 ug kg\({}^{-1}\) of the HT-2 toxin is shown. From this figure, it is possible to appreciate the good level of selectivity and sensitivity that characterizes the analytical method proposed in this study. This result confirmed the higher sensitivity of UPLC/FLD, as already stated above. Finally, two samples gave quantifiable amounts of toxins after ELISA analysis, but these levels were not confirmed by using UPLC/FLD. Additionally in this case, the result confirmed the possibility of obtaining \"false positive\" responses using the ELISA, which was, in this case, equal to 2%. This last characteristic was also confirmed by considering the overall concentrations detected, since the ELISA overestimated the content of the sum of the T-2 and HT-2 toxins compared to UPLC/FLD (mean over estimation: 17%). Regarding the overall monitoring on the presence of these two mycotoxins in cereals, the 32 confirmed quantifiable levels of two toxins (concentration > LOQ: 9.0 and 5.7 ug kg\({}^{-1}\) for the T-2 and HT-2 toxins, respectively) were detected in barley, oat, durum wheat, maize, and common wheat (12, 9, 6, 3, and 2 samples, respectively). The highest percentage of positive samples was verified in the barley and oat samples (39%), and the lowest was verified in common wheat (18%). However, the levels detected in different types of cereals samples were compared by using a one-way ANOVA (\(p<0.05\)), verifying not statistically significant differences among groups. The global area of sampling was not particularly wide (-7000 km\({}^{2}\)), so no evidence of different levels of contamination was verified. Regarding the specific occurrence of two mycotoxins, HT-2 and T-2 were  
Figure 3: Correlation between results obtained by analyzing 27 samples using the ELISA and UPLC/FLD. detected alone in 50% and 25% of samples, respectively, with mean concentrations equal to 203.0 and 125.0 \(\upmu\)g kg\({}^{-1}\), respectively. If compared to other similar surveys completed in Italy in the last few years, the prevalence of the T-2 and HT-2 toxins in cereals (samples > LOQ: 32%) was comparable to the value obtained by [PERSON] et al.