Optimisation and validation of a specific analytical method for the determination of thiram residues in fruits and vegetables by LC–MS/MS
2012
Peruga, Aranzazu | Grimalt, Susana | López, Francisco J. | Sancho, Juan V. | Hernández, Félix
Thiram is a non-systemic dithiocarbamate fungicide, which is easily degraded during sample preparation since it is affected by pH, matrix components and temperature. In this work, specific methodology for thiram analysis in vegetable (eggplant and lettuce) and fruit (strawberry) samples has been developed based on liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS). Minimising thiram degradation during standards storage and sample preparation was carefully studied. The effect of low temperature (about 5°C), addition of a dehydrating agent (Na₂SO₄ anhydrous), pH regulator (NaHCO₃), and enzymatic activity reduction (EDTA) during extraction was evaluated. The optimised procedure was validated for eggplants, lettuces, and strawberries. Satisfactory recoveries, between 80% and 106%, and relative standard deviations below 10% were obtained at 0.1 and 0.01mg/kg fortification levels (n=5). Limits of detection below 0.0012mg/kg were achieved. The validated method has been applied to eggplant and lettuce samples collected from different field trials as well as several strawberry and apple samples.
显示更多 [+] 显示较少 [-]