## 3 Results and Discussion
### Method Evaluation
Both ion transitions (\(m/z\) 289 \(>\) 70 and \(m/z\) 289 \(>\)125) in the same retention time of myclobutanil gave signals with an IR of 108% (Figure 3a). The relevant IR obtained in the standard solution was 86.7% (intensity ratio of \(m/z\) 289 \(>\) 125 to \(m/z\) 289 \(>\) 70), hence the IR was within the 30% tolerance range. The other six ion transitions were further monitored for myclobutanil in the MS/MS instrument during the confirmatory analysis. Myclobutanil is a chlorinated compound, so the A + 1 ion transitions (\(m/z\) 290 \(>\) 70, \(m/z\) 290 \(>\) 71, \(m/z\) 290 \(>\) 125, \(m/z\) 290 \(>\) 126) and A + 2 ion transitions (\(m/z\) 291 \(>\) 72, \(m/z\) 291 \(>\) 127) could also be scanned and in total of eight ion traces were used for its detection. In the chromatogram obtained from confirmatory analysis, six out of eight ion transitions appeared, but the A + 2 related transitions were missing (Figure 3b). Therefore, the presence of myclobutanil could be excluded. Indeed, the interfering matrix compound was either not chlorinated or the \(m/z\) 290 ion was its A + 2 ion. In this case, the isotopologue  
Figure 2: (**a**) Screening analysis of an herb extract. The ion transitions of primisulfuron-methyl in a neat solvent calibrant (100 ng/mL, above) and in the sample (below). (**b**) Confirmatory analysis of an herb extract for primisulfuron-methyl. The ion transitions of \(m/z\) 469 \(>\) 254 (blue line), \(m/z\) 469 \(>\) 135 (red line) and \(m/z\) 469 \(>\) 199 (green line). The spiking level was 0.010 mg/kg. Note the different retention time compared to the screening method, according to Section 2.4. (**c**) Confirmatory analysis of an herb extract for primisulfuron-methyl. The ion transition of \(m/z\) 469 \(>\) 199 was the only selective MRM for primisulfuron-methyl in this sample. The spiking level was 0.010 mg/kg. Different retention time compared to the screening method can be seen according to Section 2.4.  
pattern of the chlorinated target compound could be addressed for the identification, as recommended by [PERSON] et al. (2022); [PERSON] et al. (2022). Ruling Out the False Identification of Proplan in Elderberry (Sambucus nigra) Sample with the Help of Standard Addition  
Elderberry derived sample extracts are highly concentrated in interfering matrix compounds, even after PSA and dSPE clean-up, as presented in [PERSON] et al. (2022). On the ion transitions of problem (\(m/z\) 180 \(>\) 138 and \(m/z\) 180 \(>\) 120) distinct peaks appeared with a tolerable retention time shift (\(\Delta\) 0.01 min) and \(\Delta\) IR during the screening analysis (Figure 4a). The relevant IRs in the neat solvent and the elderberry extract were 73.2% and 79.6%, respectively. Figure 4: \(Cont\). Figure 3: (**a**) Screening analysis of myclobutanil in a white peppercorn sample. The identification criteria meet the theoretical requirements, i.e., the retention times and IR in the sample (below) were within the tolerance limits determined according to the neat solvent calibrant (100 ng/mL, above). (**b**) Confirmatory analysis for myclobutanil in a white peppercorn sample. The A + 2 ion transitions of (\(m/z\) 291 \(>\) 72, above) was the only selective MRM for myclobutanil, contributing to ruling out its false detection in this sample (below). Different retention time compared to the screening method can be seen according to Section 2.4. The arrow shows the absent of signal in the expected retention time on \(m/z\) 291 \(>\) 72 ion transition in the sample. During the confirmatory analysis, the standard addition clearly showed that this elderberry sample did not contain propham over the detection limit (Figure 4b). In the chromatogram of the fortified sample, the retention time difference between the interfering matrix peak and propham became more pronounced (\(\Delta\) 0.04 min). Indeed, the appropriate identification could not have been performed without the standard addition process.