DETERMINATION OF VAPOR-PRESSURES FOR NONPOLAR AND SEMIPOLAR ORGANIC-COMPOUNDS FROM GAS-CHROMATOGRAPHIC RETENTION DATA

Vapor pressures for nonpolar and moderately polar organochlorlne, pyrethroid, and organophosphate insecticides, phthalate esters, and organophosphate flame retardants were determined by capillary gas chromatography (GC). Organochlorines and polycyclic aromatic hydrocarbons with known liquid-phase vapor pressures (P°L) (standard compounds) were chromatographed along with two reference compounds n-C20(elcosane) and p, p'-DDT on a 1.0-m-long poly(dimethylslloxane) bonded-phase (BP-1) column to determine their vapor pressures by GC (P°GC). A plot of log P°Lvs log P°GCfor standard compounds was made to establish a correlation between measured and literature values, and this correlation was then used to compute P°Lof test compounds from their measured P°GC-P°Lof seven major components of technical chlordane, endosulfan and its metabolites, α-hexachlorocyclohexane, mlrex, and two components of technical toxaphene were determined by GC. This method provides vapor pressures within a factor of 2 of average literature values for nonpolar compounds, similar to reported interlaboratory precisions of vapor pressure determinations. GC tends to overestimate vapor pressures of moderately polar compounds. © 1990, American Chemical Society. All rights reserved.