Assessing calibration methods for fenuron determination in carrot juice via GC–MS with salt-assisted switchable solvent microextraction

An accurate and precise analytical method was established for the determination of fenuron in carrot juice samples. Salt-assisted switchable solvent-liquid phase microextraction (SA-SS-LPME) was performed to achieve a lower detection limit. Three different calibration methods were compared to quadruple isotope dilution (ID⁴) in terms of accuracy and precision. Under the optimum SA-SS-LPME-GC-MS conditions, the linear range, coefficient of determination, limit of detection (LOD), and limit of quantitation (LOQ) were calculated as 0.12–2.85 mg/kg, 0.9988, 0.05 mg/kg and 0.15 mg/kg via the external standard calibration method, respectively. In addition, the internal calibration strategy was also implemented and the linear range, coefficient of determination, LOD and LOQ were found to be 0.12–5.13 mg/kg, 0.99996, 0.05 mg/kg and 0.17 mg/kg, respectively. Percent recovery results were recorded as 104.5%–118.1% (± 1.9–7.2) via the external standard calibration, 75.1%–115.0% (± 1.7–6.2) via the matrix–matching calibration, 89.7%–100.7% (± 1.8–6.3) via the internal standard calibration and 99.6%–102.0% (± 1.2–2.3) via the ID⁴ strategy. The recovery results obtained using the ID⁴ strategy demonstrate the advantage of integrating SA-SS-LPME-GC-MS with this approach.