A screening method for polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and non-ortho polychlorinated biphenyls (PCBs) in biologicalmatrixes

We have developed a screening method for analyzing tetra- and penta-chlorin ated dibenzo -p-dioxins/dibenzofurans (CDD/F), octa-CDF, and non-ortho poly chlorinated biphenyls (PCBs) in biological matrixes to reduce the cost and time of dioxin analysis. Spiked control Long Evans (LE) rat liver, adipose tissue, serum, placenta, and whole fetus were analyzed to validate the meth od and to determine the method detection limit (MDL). Mixed with formic aci d, serum samples were extracted with n-heptane. Solid tissues were ground t o powder with anhydrous sodium sulfate and were sonicated with acetonitrile ; the supernate was passed through a C-18 cartridge, and analytes were elut ed with n-heptane. A dual-column unit composed of 40% H2SO4-coated silicic acid and activated acidic alumina was used for further cleanup. The extract s after cleanup were analyzed by high-resolution gas chromatography (HRGC)/ high-resolution mass spectrometry(HRMS) using an isotope dilution techniqu e. The method needed half the time and one-fifth the amount of organic solv ents for sample preparation, compared to traditional liquid/liquid or Soxhl et extraction. The method also saved two-thirds of the time on GC/MS analys is. Sub-pg/g level of sensitivity was achieved using gram-sample quantities .