Estimation of Koc values for deuterated benzene, toluene, and ethylbenzene, and application to ground water contamination studies

Sorption partition coefficients between water and organic carbon (Koc) for deuterated benzene, toluene, and ethylbenzene have been estimated by measuring values of the octanol-water partition coefficient (Kow) and HPLC retention factors (k1), which correlate closely to values of Koc. Measured values of log Kow for non-deuterated and deuterated toluene are 2.77 (+/- 0.02) and 2.78 (+/- 0.04), respectively, indicating that within experimental error, log Koc for deuterated and non-deuterated toluene are the same. The HPLC method provides greater precision, and yields values of delta log Koc (= log Koc [deuterated]-log Koc [non-deuterated]) of -0.021 (+/- 0.001) for benzene, -0.028 (+/- 0.002) for toluene, and -0.035 (+/- 0.003) for ethylbenzene. The small values of delta log Koc demonstrates that deuterated compounds are excellent tracers for the hydrologic behavior of ground water contaminants.