Calibration curves were established applying the methodof standard additions: the samples were fortified with knownamounts of analytes before sample preparation with the LOQsto be the lowest levels for each analyte. This calibration methodwas selected in order to compensate for potential matrix effectsoccurring during sample preparation and analysis. The calculatedcalibration curves (seven points, each calibration point was deter-mined in triplicate) gave a high level of linearity for all targetanalytes with coefficients of determination (R2) ranging between0.9950 and 0.9999. Moreover, residual plots were prepared for eachanalyte. Individual residuals were scattered randomly above andbelow zero, with standard deviations ranging from 0.33% to 7.5%,lower than ±20% (±10% when the Maximum Residue Limit—MRL isapproached or exceeded) from the calibration curve, as suggestedby SANCO/12571/2013 document.