Related Experiment Video
Updated: Aug 29, 2026

In Silico Modeling Method for Computational Aquatic Toxicology of Endocrine Disruptors: A Software-Based Approach Using QSAR Toolbox
Published on: August 28, 2019
Predicting toxic equivalence factors from 13C nuclear magnetic resonance spectra for dioxins, furans, and
Dan A Buzatu1, Richard D Beger, Jon G Wilkes
1Division of Chemistry, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas 72079, USA. dbuzatu@nctr.fda.gov
Abstract:
Two quantitative spectrometric data-activity relationships (QSDAR) models have been developed relating 29 dioxin or dioxin-like molecules to their toxic equivalence factors (TEFs). These models were based on patterns in simulated 13C nuclear magnetic resonance (NMR) data with the patterns defined by comparative spectral analysis (CoSA). Two versions of CoSA multiple linear regression (MLR) models using 7 or 10 spectral bins had, respectively, explained variances (r2) of 0.88 and 0.95, and leave-one-out (LOO) cross-validated variances (q2) of 0.78 and 0.88. A third, artificial neural network model--using a feed forward, back propagating, three-layer neural network--produced an r2 of 0.99, a LOO q2 of 0.82, and a leave-three-out q2 of 0.81. A postulated reason that the results of these QSDAR models are better than traditional quantitative structure-activity relationship (QSAR) models is based on the difference in descriptors rather than on any differences in pattern recognition approach. Results suggest that the 13C NMR spectral data contain molecular quantum mechanical information more reflective of each molecule's biochemical properties than do the calculated electrostatic potentials and molecular alignment assumptions used in developing QSAR models. The QSDAR models provide a rapid, simple way to model the toxicity of dioxin and dioxin-like compounds.
Related Concept Videos
¹H NMR: Interpreting Distorted and Overlapping Signals
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are slanted or...
¹³C NMR: ¹H–¹³C Decoupling
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
2D NMR: Overview of Heteronuclear Correlation Techniques
¹H NMR: Complex Splitting
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied first.
¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)
UV–Vis Spectroscopy: Woodward–Fieser Rules
