## 3 Results  
### Method Validation  
As recommended by the European regulations (European Commission SANTE 2017/11813/EC, European Commission Regulation 2017/644/EC and European Commission Decision 657/2002/EC), the method validation is an essential prerequisite to provide accurate and reliable results during the official monitoring and risk-assessment studies. Moreover, laboratories in charge of food and animal feed control need analytical methods able to identify/quantify the highest number of compounds within the same analysis, to optimize both times and costs. In this regard, several analytical approaches were developed during the last years for the multi-detection of environmental contaminants [24], drug residues [25], heavy metals [26], and other toxic compounds that may be present in food. Therefore, this GC-MS/MS analytical method was coupled to a rapid QuEChERS procedure for the multi-residue pesticide analysis. The method was validated through the evaluation of linearity, detection and quantification limits, selectivity, precision, recovery, and measurement uncertainty. The linearity test was performed by the evaluation of correlation coefficients of the calibration curves obtained by the ratio between the analyte peak area and IS peak area vs. the pesticide concentration in the range 0.025-0.500 mg L\({}^{-1}\). For all pesticides, the calculated correlation coefficients were always higher than 0.9900. The signal-to-concentration ratio (y/x) was calculated for each experimental point to evaluate the goodness-of-fit of the data to the calibration curve. Then, the xi/y ratios were checked to ensure that their deviation from the mean value of the signal-to-concentration ratio never exceeded \(\pm\)10%. The absence of systematic instrumental bias was confirmed by the confidence interval for the intercept that included the zero value at 95% confidence level. By [PERSON]'s fitting test [PERSON] (1975) the residual variances, resulting from the linear and the quadratic calibration function, were compared by an F-test and the hypothesis H0 (no significant difference between the residual variances) was accepted for all pesticides. Therefore, calibration straight-lines rather than over curvilinear or non-linear models well fitted the experimental data. The instrumental detection (LODs) and quantification (LOQs) limits were calculated by standard solution analysis, according to the following equations: LOD = 3.3s\({}_{\text{a}}\)/b; LOQ = 10s\({}_{\text{a}}\)/b, where s\({}_{\text{a}}\) was the standard deviation of the intercept and b the slope of the regression line obtained from the calibration curve [PERSON] (1975). LODs and LOQs were in the range 0.015-0.198 \(\mu\)g L\({}^{-1}\) and 0.045-0.599 \(\mu\)g L\({}^{-1}\), respectively. Similarly, LODs and LOQs in the matrix were evaluated by matrix-matched standard calibration in wheat blank samples at concentrations of 0.025-0.050-0.100-0.250 and 0.500 mg kg\({}^{-1}\) for each pesticide. In the matrix, LODs and LOQs ranging from 0.018-0.168 \(\mu\)g kg\({}^{-1}\) and 0.053-0.510 \(\mu\)g kg\({}^{-1}\) were obtained, as reported in Table 2. These values, considerably lower than the legal limits established by the European Community for the pesticide residues in cereal samples, confirmed the high sensitivity of the described method at trace levels, reducing the risk of false-negative results.