Comparison of three different calibration methods and quadruple isotope dilution strategy to design more accurate quantitation method for the determination of monuron in potato flour samples by HPLC-MS/MS

A highly accurate and precise quadruple isotope dilution (ID⁴) strategy was employed for the determination of monuron in potato flour samples. Isotopic compositions were monitored by tandem mass spectrometry (MS/MS). Isotopically labelled monuron substance (monuron– d ₆ ) was synthesized in our research laboratory. After optimizing HPLC-MS/MS system, limit of detection (LOD), limit of quantitation (LOQ) and linear working range (LWR) were figured out as 25.28 ng/kg, 84.27 ng/kg and 0.08–27.55 μg/kg, respectively. ID⁴ method was carried out by spiked potato flour samples. Percent recovery results (%RRs) for HPLC-ID⁴-MS/MS system were varied from 99.0 % to 101.7 % with low standard deviation values (1.2–2.3 %). HPLC-ID⁴-MS/MS method gave excellent accuracy and precision to determine monuron at trace levels in potato flour samples when compared to external, internal and matrix matching calibration strategies. According to the current literature, no study has been employed to determine monuron in potato flour samples by the HPLC-ID⁴-MS/MS system.