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

We have developed a screening method for analyzing tetra- and penta-chlorinated dibenzo -p-dioxins/dibenzofurans (CDD/F), octa-CDF, and non-ortho polychlorinated 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 method and to determine the method detection limit (MDL). Mixed with formic acid, serum samples were extracted with n-heptane. Solid tissues were ground to powder with anhydrous sodium sulfate and were sonicated with acetonitrile; the supernate was passed through a C-18 cartridge, and analytes were eluted with n-heptane. A dual-column unit composed of 40% H2SO4-coated silicic acid and activated acidic alumina was used for further cleanup. The extracts after cleanup were analyzed by high-resolution gas chromatography (HRGC)/ high-resolution mass spectrometry(HRMS) using an isotope dilution technique. The method needed half the time and one-fifth the amount of organic solvents for sample preparation, compared to traditional liquid/liquid or Soxhlet extraction. The method also saved two-thirds of the time on GC/MS analysis. Sub-pg/g level of sensitivity was achieved using gram-sample quantities.