2.7. Instrumental Validation

To evaluate the instrumental parameters such as linearity, precision or detection (LOD) and quantification (LOQ) limits, different standard solutions were prepared and analysed on the HPLC-QqQ-MS/MS. Linearity was evaluated by analyzing standard solutions between 0.05–10 mg/L in water-MeOH (90:10, v/v). Repeatability and reproducibility were evaluated at two concentrations levels, low (0.5 mg/L) and high (2.5 mg/L). Repeatability was obtained by analyzing the standard solution six times in one day (n = 6) and reproducibility was evaluated by analyzing the standard solution three times, on three different days (n = 9). LOD and LOQ were calculated as three times and ten times the signal-to-noise ratio (S/N), respectively, obtained after analyzing the standard solution with the lowest concentration, 0.05 mg/L for AA, MF and HMF and 0.5 mg/L for F.