Determination of Distribution Coefficients of Priority Polycyclic Aromatic Hydrocarbons Using Solid-Phase Microextraction

Abstract

The determination of distribution coefficients is important for prediction of the chemical pathways of organic compounds in the environment. Solid-phase microextraction (SPME) is a convenient and effective method to measure the distribution of chemicals in a two-phase system. In the present study, the SPME distribution coefficient (K(spme)) of 16 priority aromatic hydrocarbons (PAHs) was determined with 100-microm poly(dimethylsiloxane) (PDMS) and 85-microm polyacrylate (PA) fibers. The partition coefficients and LeBas molar volumes were used to describe the linearity of the log K(spme) values of PAHs. Also, the validation of the distribution coefficient was examined using different sample volumes. The extraction time was dependent on the types of PAHs, and 20 min to 60 h was needed to reach equilibrium. The determined log K(spme) values ranged from 3.02 to 5.69 and from 3.37 to 5.62 for 100-microm PDMS and 85-microm PA fibers, respectively. Higher K(spme) values of low-ring PAHs were observed using 85-microm PA fiber. Good linear relationships between log K(ow) and log K(spme) for PAHs from naphthalene to benzo[alpha]pyrene and from naphthalene to chrysene for 100-microm PDMS and 85-microm PA fibers, respectively, were obtained. The correlation coefficients were 0.969 and 0.967, respectively. The linear relationship between log K(spme) and the LeBas molar volume was only up to benz[alpha]anthracene for 85-microm PA fiber and up to chrysene for 100-microm PDMS fiber. Moreover, the effect of sample volume can be predicted using the partition coefficient theory and excellent agreement was obtained between the experimental and theoretical absorbed amounts of low-ring PAHs. This result shows that the determined log K(spme) is more accurate than the previous method for estimating analytes with log K(ow) < 6 as well as for predicting the partitioning behaviors between SPME fiber and water.

Array capillary in-tube solid-phase microextraction: A rapid preparation technique for water samples

“…Since the distribution coefficient K of the PAHs is large enough (10 3 -10 5 ) [31], the approximation, m 1 2m 2 K, could be made. Besides, V s KV f as the extraction is a "negligible depletion" procedure [29].…”

High-temperature solvent stability of sol–gel germania triblock polymer coatings in capillary microextraction on-line coupled to high-performance liquid chromatography

“…Taking into account the error associated with concentration measurements of the sample solutions, C 0, and the run-to-run repeatability of the amount of analyte extracted by the sol-gel germania triblock polymer coated microextraction capillary, n, the estimated RSD values for K cs ranged from 5.1 to 8.4%. Determining the K cs is useful in comparing extraction abilities of the sol-gel germania triblock polymer coating for different analytes since K cs values directly reflect extraction capabilities of the coating [38,39], unlike detection limits, which may also vary depending on detector response characteristics for each of the analytes. K cs values are also useful for determining original concentrations of target analytes [38,39].…”

Development of a polydimethylsiloxane film‐based passive dosing method in the in vitro DR‐CALUX® assay

“…Ter Laak et al [23] determined a log K fw for BkF of 5.28 for PDMS fibers loaded with BkF to dose this compound to water. Doong and Chang [24] also used PDMS fibers for dosing to water and reported a log K fw of 5.33 for BkF. In addition to the partitioning between PDMS and medium in the DR-CALUX assay, another partitioning process plays a role, namely, the partitioning between proteins and medium.…”