## 3 Results
### Method Validation Results  
The linearity assessment was performed based on the correlation coefficient of the compounds in the concentration range of 0.03-0.2 \(\mathrm{\SIUnitSymbolMicro m}\). Table S6 shows the regression equations and the corresponding correlation coefficients of each compound when analyzing a standard solution prepared by dilution in a solvent and a standard solution prepared by dilution in a sample extract. According to these results, all compounds show excellent linearity with values R\({}^{2}\geq\) 0.99. The comparison of the slope of the regression lines between the pure standard and the standard diluted in sample extract shows a considerable matrix effect when the slopes of the regression lines differ by more than 40% [33]. According to Table S7, the effect of the substrate is significant for 25% of the compounds, while for 75% it is negligible. For the compounds carbendazim, deltamethrin, etofenprox, fenpyroximate, lambda-cyhalothrin, pyrolostrobin, pyriproxyfen, spinosyn A, spinosyn D, _tau_-fluvalinate, thiabendazole, and thiamethoxam, the matrix effect causes signal enhancement. The results are graphically pre  
Figure 5: Percentage of pesticides and mycotoxins with acceptable recoveries in the range 70–120% in the absence of acids and the presence of 1% acetic acid, 5% acetic acid, and 1% formic acid. sented in Figure 6, and the bars exceeding the black horizontal line indicate the compounds that are significantly affected by the matrix, causing signal enhancement. Analytes for which no significant matrix effect was observed could be quantified using the standard calibration curve, while those analytes presenting significant matrix effect could be quantified using the matrix-matched curve. Figure 6: Matrix effect (%) results: (**a**) abametein (B1a), acetamipid, acrimathrin, boscalid, bupirimate, carbendazim, chlororyrifos, chlororyrifos-methyl, clofentezine, clothianidin, cyprocanazole, cyprodinil, deltamethrin, difenoconazole, etofenprox, fenbuconazole, fenpyroximate, flonicamid, fluidoxonil, fluopryam, fluquinconazole, flutrifal, hexythiazox, imazalli; (**b**) indoxacarb, kresoxym-methyl, lambda-cyhalothrin, methoxyfenozide, myclobutanil, penconazole, primicarb, pyracolstrobin, pyrimethanil, pyriproxyfen, spinosyn A, spinosyn D, spirodiclofen, tau-fluvalinate, tebuconazole, tebufenopyrad, thiabendazole, thiaeloprid, thiaethoxar, trifikovstrobin, alternaiol (AOH), alterna-iol monomethyl ether (AME). The bars of the compounds exceeding the black horizontal line indicate they are significantly affected by the matrix. The bias of the method was assessed by means of relative percentage of recovery at four concentration levels (0.01, 0.03, 0.1, and 1 \(\mathrm{\SIUnitSymbolMicro g}\)/g). All validation results are presented in Table 1. The results show that 66% of the studied analytes spiked at 0.01 \(\mathrm{\SIUnitSymbolMicro g}\)/g concentration level and 94% of the analytes spiked at 0.03, 0.1, and 1 \(\mathrm{\SIUnitSymbolMicro g}\)/g presented satisfactory recoveries. The analytes chlororprifos and clofentzeine at 0.03, 0.1, and 1 \(\mathrm{\SIUnitSymbolMicro g}\)/g showed recoveries \(<\)70%, while the calculated recoveries for the rest of the compounds ranged between 70 and 107%. Overall, the method is accurate for the majority of the compounds at concentration levels equal to or greater than 0.03 \(\mathrm{\SIUnitSymbolMicro g}\)/g. In contrast, at lower concentrations of 0.01 \(\mathrm{\SIUnitSymbolMicro g}\)/g, the number of the compounds accurately determined by the proposed method decreases, which is negligible as the MRLs of the compounds are higher than this concentration level. Chloryprifos was detected at 0.01 \(\mathrm{\SIUnitSymbolMicro g}\)/g since the MRL is equivalent to this concentration level. For chloryprifos-methyl, very erratic results were noticed during the validation procedure (very inconsistent recoveries among concentration levels), and thus the method was not validated for this compound.