Comparison of Sample Extraction Methods for the Determination of Bis(p-chlorophenyl)dichloroethylene (p,p'-DDE) in Rice Flour Using Isotope Dilution Mass Spectrometry

The determination of pesticide residues in agricultural products and food is great public and regulatory concerns. It is well known that the measurement results of the pesticides show a strong dependence on the extraction method used and following sample clean-up methods employed for the analysis.1 In this respect, isotope dilution mass spectrometry (IDMS) has been wildly accepted as a reliable analytical method for the accurate determinations of trace organic compounds in complex matrix as the method overcomes difficulty of correcting recovery yield in sample preparation and separation. Therefore, the IDMS method makes the measurement results traceable to the SI units directly with-out significant empirical correction factors.2-4 For usual pesticide analysis, an ideal extraction method should yield quantitative recovery of target analytes withou