Solid-water partition coefficient

Hence, the solid-water partition coefficient can be approximated by (Eq. 9-22) ... 

Unlike a Henry s law constant, whose value depends mainly on temperature, the value of a solid-water partition coefficient depends on the type of solid, and may also be affected by factors such as pH and ionic strength. There is considerable uncertainty in predicting Kd values for inorganic chemicals often must be measured in the laboratory. For many organic chemicals, however, a method for approximating values exists, based on the properties of the solid sorbent, particularly its concentration of organic carbon, and the properties of the sorbate. The sorbate properties necessary for predicting values are described below further estimation techniques are presented in Section 3.5. 

A series of studies has been made by Yalkowsky and co-workers. The so-called general solubility equation was used for estimating the solubility of solid nonelectrolytes [17, 18]. The solubility log S (logarithm of solubility expressed as mol/L) was formulated with log P logarithm of octanol/water partition coefficient), and the melting point (MP) as shown in Eq. (11). This equation generally... 

Water solubility, dissociation constant(s) and n-octanol/water partition coefficients allow one to predict how an analyte may behave on normal-phase (NP), reversed-phase (RP), or ion-exchange solid-phase extraction (SPE) for sample enrichment and cleanup. 

Water 70pgL acetone 560gL ethanollSgL toluene400g L n-hexane 14g L n-octanol6.8g Yellow to orange odorless crystalline solid density 1.54gem at 20°C octanol/water partition coefficient (log P)5.45 at 25 °C... 

The studies with barbiturates revealed that the logarithm of the retention time is linearly related to the octanol/water partition coefficients [66,67]. It has been observed that the retention index of the drug is linearly related to the octanol/water partition coefficient (logP), and that results are very close to that of the 2-keto alkane standard (solid line in Fig. 15.9). 

Estimation is easier and less time-consuming because use is made of empirical relationships between the BCF and physicochemical properties of the compound, such as water solubility (S) [42-48], Km, (solid organic carbon/water partition coefficient) [48], Kmw (membrane water partition coefficient), iipw (liposome water partition coefficient) [49], critical micelle concentration (CMC) [45], steric factors, molecular weight [47,48], and others. The most common regression method is the estimation of BCF from the octanol-water partition coefficient (Kovl) [18,42,44-48,50,51],... 

The most common partition coefficient encountered in environmental work (Sect. 2.1.4) is the octanol water partition coefficient (K0VI) and the solid phase carbon-water partition coefficient (Koc). A partition coefficient for dissolved organic matter-water (i. e., Kd ()M) or dissolved organic carbon-water (i. e., Kd oc) occasionally appears in the literature. In the case of PCBs, Boyd and Sun [378] defined a partition coefficient for residual transformer oil and water as Kd oil, while Sun and Boyd [379] defined a coefficient for PCB dielectric fluid-water as Kd pen-These authors [378,379] identified a total partition coefficient that com-... 

Paschke, A. and Popp, P. 2003, Solid-phase microextraction fibre-water distribution constants of more hydrophobic organic compounds and dieir correlations widi octanol-water partition coefficients. J. Chromatogr. A 999 35-42. 

The partitioning of 1,3-DNB in water between water and the suspended solid and sediment has been estimated. Simulation studies based on the octanol-water partition coefficient predict that >99% of... 

DNB will remain in the water column and <1% will be adsorbed to suspended solid and sediment (ERA 1991b). 1,3,5-TNB with an octanol-water partition coefficient value lower than 1,3-DNB (see Table 3-2), is expected to exist almost exclusively in the water column. 

PBDEs adsorb strongly onto suspended solids and sediments in the water column. Volatilization of PBDEs from water surfaces will be attenuated by adsorption, and thus is notan important fate process. Sediment-water partition coefficients (K,) have been measured for several components of commercial... 

For this problem, assume an air-water partition constant, cH4aw = 30 and an organic carbon-water partition coefficient Kch oc = 10 L-kg-1oc. Also assume the air-plus-water-filled soil porosity is 0.4, the soil solid density is 2.5 g-mL"1, the soil water content is 12% by weight, and the organic carbon content is 5% by weight. Finally, assume the methane biodegradation obeys d[methane]totai/[Pg.774]

Vaes, W. H. J., E. U. Ramos, C. Hamwijk, I. von Holsteijn, B. J. Balaauboer, W. Seinen, H. J. M. Verhaar, and J. L. M. Hermens, Solid phase microextraction as a tool to determine membrane/water partition coefficients and bioavailable concentrations in in vitro system , Chem. Res. Toxicol., 10, 1067-1072 (1997). 

Nakamura, M., Suzuki, T., Amano, K., Yamada, S. (2001) Relation of sorption behavior of agricultural chemicals in solid-phase extraction with their n-octanol/water partition coefficients evaluated by high-performance liquid chromatography (HPLC). Anal. Chim. Acta 428, 219-226. 

---