DEVELOPMENT AND INDEPENDENT LABORATORY VALIDATION OF AN ANALYTICAL METHOD FOR THE DETERMINATION OF OXYACETANILIDE RESIDUE AND ITS METABOLITES IN TRITICUM AESTIVUM (GRAIN & STRAW) BY LC-MS/MS TANDEM MASS SPECTROMETRY

A novel and robust high-throughput liquid chromatography/tandem mass spectrometry (LC-MS/MS) method was developed for the determination of residue of oxyacetanilide as its metabolitesnamely the N-fluorophenyl-N-isopropyl in Triticum Aestivum (Grain & Straw). The performance characteristics included linearity, specificity (matrix interferences), LOQ, reproducibility (%RSD) and trueness (%recovery). The method is, therefore, compliant with the definition of the residue for oxyacetanilide containing the N fluorophenyl-N-isopropyl as oxyacetanilide equivalent. This design specifically evaluates the effects of sample extraction interferences. Two precursors/product ion transitions (154/112 and 154/95) were monitored for target compound to achieve true positive identification. 5 g of the sample was taken with water containing 1 N H2SO4 and KMnO4 in RBF. Afterwards, 1 g of NaHSO3- NaHSO4 mixture was mixed. Conc. H2SO4 was added through the condenser and the mixture was heated under reflux for 20 h. The mixture was cool for approx. 30 minutes and added water. An amount of this extract was taken for liquid liquid extraction. CH2Cl2 was added for 1 minute and the organic phase was disposed of, and 50 % aq. NaOH was added into the aq. Phase. CH2Cl2 was again added and shaken for 1 min. The lower phase was filtered and repeated twice. 0.10 % HCOOH in water was added to the extract. The mixture was ultra-sonicated for about 30 seconds. This research highlights the satisfactory linearity, trueness, and reproducibility were achieved within the linear range 0.00008- 0.01 mg/L with a correlation co-efficient >0.99. %RSD and % recovery of the analytical method was determined from recovery experiment (n=5 replicates) at 0.01 mg kg-1 (grain) and 0.05 mgkg-1 (straw). The mean recovery of the targeted compound in wheat grain and straw obtained wasin the range of 72.30 ? 80.50 % with associated % RSD values lower than or equal to 7% for quantification and confirmation.