Equilibrium and kinetic solid-phase microextraction determination of the partition coefficients between polychlorinated biphenyl congeners and dissolved humic acid

Automated method for determination of dissolved organic carbon–water distribution constants of structurally diverse pollutants using pre‐equilibrium solid‐phase microextraction

“…The SDs were calculated (Table ) for the log K DOC values (Equation 7) and found to range between 0.02 log units and 0.32 log units ( n = 3). Wang et al and Prosen et al measured comparable SD values using nd‐SPME for compounds with similar properties (0.01–0.22 and 0.1–0.4, respectively), and Xie et al reported SD values of 0.03 log units to 0.65 log units.…”

Solid-phase microextraction to determine micropollutant–macromolecule partition coefficients

“…Compared with the Risticevic protocol, the main novelty in the current protocol is the application of SPME to the study of micropollutant-macromolecule interactions, in which the variation of free micropollutant concentration is measured, resulting in the calculation of partition coefficients, rather than the determination of free concentrations as such. SPME, and in particular nd-SPME, which extracts <5% of the micropollutant, has previously been applied to study micropollutant-macromolecule interactions and to determine affinity constants 27 and partition coefficients 29,30,33,50 .…”

“…The approach described in this protocol can be, and has been, used to determine the partition coefficients of many compounds, including hormones 27,28 , polybrominated diphenyl ethers 29 , polychlorinated biphenyl congeners 30 , pesticides [31][32][33] and polycyclic aromatic hydrocarbons 34 ; examples of macromolecules used in these experiments include proteins 27 , DOC 29 , humic acids 30 and particulate matter such as algae 31 . DOC is composed of a heterogeneous mixture of organic compounds with molecular weights ranging from less than 100 to over 300,000 Da (g/mol), the majority of which is typically made up of fulvic or humic acid.…”

The kinetics of solid-phase microextraction measured for freshly added and aged hydrophobic compounds in two different soils

“…Thus, the quantity of the analyte extracted by the fibre is proportional to its concentration in the sample as long as equilibrium is reached. In the case of non-equilibrium SPME, the extracted amount of an analyte depends upon the extraction time and the time dependence can be expressed by a simple exponential term [13,14]. The non-equilibrium SPME requires shorter extraction times in comparison to the equilibrium SPME [15].…”

“…Triplicate samples were prepared for each soil and sampling point. The SPME fibres were exposed for 1, 2, 4, 7, 10, 14,18,22,25,30,40 and 50 days on a shaker (130 rpm) at 22 ± 2°C in the dark (dark vials wrapped with aluminium foil were used). At each sampling point, fibres were removed from the soil slurry, inspected for damage, carefully wiped with tissue to remove residual water and soil, and transferred to a GC vial containing 2 mL of hexane and recovery standards (deuterated phenanthrene and pyrene, and PCB 155 for chlorinated compounds).…”