“…A reason often proposed for this observation is the fact that nonplanar PAC are cyclic compounds with structures more compact than those of the calibration compounds, so they will elute later than predicted by a MW-based calibration curve (10,(31)(32)(33)(34)(35). Nevertheless, evidence is lacking that any general 0 Chemical suppliers: (AC) Aldrich Chemical Co., Milwaukee, WI; (AN) Analabs Div., Foxboro Analytical; (CA) Caledon-American, American Bioanalytical, Natick, MA; (CO) Columbia Organic Chemical; (CS) Chem Servies, Inc., Chester, PA; (LS) Lancaster Synthesis, Inc.; (SN) Synthetic chemical.…”