Residual Behavior and Consumer Safety Evaluation of Flometoquin, Flupyradifurone, and Flonicamid in Tomatoes Using QuEChERS–HPLC/DAD

An effective analytical technique for the simultaneous determination of flometoquin, flupyradifurone, and flonicamid residues was assessed in the tomato fruit, which were randomly collected at intervals of 0, 1, 3, 5, 7, 10, 15, and 21 days following treatment. The residue levels were conducted by employing the QuEChERS (quick, easy, cheap, effective, rugged, and safe) methodology as a pre-treatment procedure, along with solid phase extraction (SPE) for clean-up, followed by analysis with high-performance liquid chromatography equipped with diode-array detection (HPLC/DAD). The method showed good recoveries (93.74–102.44% for flometoquin, 92.30–105.90% for flupyradifurone, and 94.94–108.11% for flonicamid) at 0.1, 0.5, and 1 mg/kg, with RSDs below 20%. Calibration curves displayed excellent linearity (R² > 0.99). The residual half-life (RL50) of the evaluated pesticides on tomato fruits was 4.85, 0.8, and 5.16 days for flometoquin, flupyradifurone, and flonicamid, in that order. In line with the maximum residue level (MRL) of 1, 1, and 0.5 mg/kg, respectively. The pre-harvest interval (PHI) was set at 3, 5, and 7 days, respectively. The hazard quotients (HQs) for all three insecticides remained below 1 throughout the monitoring period, with maximum values of 0.59 for flometoquin, 0.17 for flupyradifurone, and 0.08 for flonicamid at day 0. These values gradually declined over time, indicating a decreasing exposure risk. As all HQ values were significantly less than 1, the estimated dietary intake of treated tomato fruits poses no significant health risk to consumers.