Determination of gas-particle partitioning parameters and indoor air concentrations of synthetic musk compounds

Abstract

Gas-particle partitioning of compounds is the key process determining the fate of chemical in the environment. The partitioning process can be modeled depending upon dominancy of being adsorptive or absorptive partitioning and referred with partition coefficient (Kp m3.μg-1). Kp is related to liquid phase vapor pressure of a compound of interest. Due to difficulty related to model parameters, researchers have been developed a parameter called octanol air partition coefficient, KOA which can be directly measured and used to estimate Kp. Synthetic musk compounds (SMCs) are the one group of semi volatile organic compounds which are resistant to degradation, lipophilic and have moderate vapor pressures. They have been widely used in detergents, soaps, cosmetics, perfumes to give nice odorous effect for the product of interest. Most of their chemical properties values based on estimation methods. This study designed to measure octanol-air partition coefficients (KOA) and supercooled liquid vapor pressures (PL) by GC retention time method as a function of temperature to estimate gas-particle partitioning of SMCs. In addition ten indoor air gas and particulate phase samples were collected from a university cafeteria to determine experimental partition coefficient in the indoor air environment. The log KOA and log PL values of synthetic musk compounds were ranged between 6.42 to 8.77 and 0.52 to -4.53, respectively at 25 0C. All of the compounds were detected in the gas phase and the concentrations ranged from 0.27 ng/m3 to 106.8 ng/m3. In the particulate phase only DPMI, ADBI, ATII, MX and MK were detected in the range of 0.06 ng/m3 to 210.5 ng/m3. Although the correlation between the gas-particle partitioning coefficient (KP) and PL was found as weak, KOA was determined as a good descriptor for gas-particle partitioning process.