Predicting gas chromatographic retention times for the 209 polybrominated diphenyl ether congeners

A gas chromatographic relative retention time (GC-RRT) model was developed to predict retention times of the 209 individual polybrominated diphenyl ether (PBDE) congeners. Using the available 46 PBDE standards with mono- to deca-bromination, a multiple linear regression equation of the form RRT=b0+b1(no. o-Br)+b2(no. m-Br)+b3(no. p-Br)+b4(μ)+b5(ln MW) was used to predict the RRTs of the remaining 163 PBDE congeners. Molecular descriptors in the model included the number of ortho-, meta-, and para-bromine substituents (no. o-Br, m-Br and p-Br, respectively), the semi-empirically calculated dipole moment (μ), and the natural logarithm of molecular weight (MW). A high level of predictability (R2=0.9972) was obtained for the model.