Inclusion of 13C12-labelled mono-, di-, and tri-chlorinated dibenzo-p-dioxin and dibenzofuran standards in US EPA methods 0023A/8290

13C12-Labelled mono-, di-, and tri-chlorinated dibenzo-p-dioxin (CDD) and chlorinated dibenzofuran (CDF) standards have been tested for their applicability to standard EPA sampling and analytical Methods 0023A/8290. These methods target for analysis only the tetra- through octa-CDD/CDF homologues. Extension of the isotope dilution method to include those lower chlorinated homologues is important toward obtaining reliable species concentration data on the complete, mono- to octa-chlorinated homologue profile. These data will improve our ability to model poly-CDD/CDF concentrations through understanding mechanisms of poly-CDD/CDF formation, chlorination, and dechlorination.