Phase Partition Coefficients Research Articles

Impact on sulfadiazine bio-accessibility in soils through organic diffusive gradients in thin films (o-DGT): Differentiation based on microplastic polymers, aging, and soil properties

Due to the similar sources of swage irrigation, organic fertilizer, and sludge application, microplastics (MPs) and antibiotics coexist inevitably in the agriculture soils. However, the impacts of MPs with different polymer types and aging status on the bio-accessibility of co-existing antibiotics in soils remained unclear. Therefore, we using the diffusive gradients films for organic compounds devices (o-DGT) to evaluated the distribution of sulfadiazine (SDZ) in both paddy soil and saline soil amended with 0.5 % (w/w) MPs. Four polymer types (polyethylene: PE, polypropylene: PP, polyamide: PA, and polyethylene terephthalate: PET) and two aging statuses (aged PE and aged PP) of MPs were used in this study. Results showed that soil properties significantly influence the partition of SDZ in soil and soil solution, and SDZ gained a lower degradation rate but higher mobility in saline soil. MPs pose different impacts on partition of SDZ between paddy soil and saline soil. Notably, PP reduced the labile solid phase-solution phase partition coefficient (Kdl) by 17.7 % in paddy soil, while PE, PP, and aPE increased the Kdl value by 2.00, 1.62, and 2.81 times in saline soil. Besides, in saline soil, all the MPs reduced the SDZ concentration in the soil solution, while significantly increased the SDZ in o-DGT phase. Conversely, MPs did not impact the SDZ's o-DGT concentration in paddy soil. Additionally, MPs increased the R value of SDZ in two soils, especially in saline soil. It suggested that MPs could potentially enhance the resupply of SDZ from soil to plants, particularly under saline conditions. Furthermore, aged MPs had a more pronounced effect on these indicators compared to virgin MPs in saline soil. Therefore, MPs in soil poses a potential risk for biota's uptake of SDZ, particularly in fragile environment. Moreover, the risk intensifies with aged MPs.

Determination of the phase ratio of a dehydroabietic-acid-bonded silica-gel chromatographic stationary phase and its effect on separation thermodynamics

Rosin-based chromatographic columns are widely used for separation purposes, but, to date, their phase ratios (Φ) have been imprecisely measured. This affects the understanding of their separation mechanism and the calculation of related thermodynamic parameters. In this study, a stationary phase was synthesized by bonding dehydroabietic acid (DA) to silica gel (Si-DO) and applied for reversed-phase liquid chromatography. The distribution coefficient (Kdm) of methyl dehydroabietate (MD), which has the same structure as the bonded phase of Si-DO, was used as a surrogate for the determination of the equilibrium coefficient (K) of Si-DO, and the Kdm values of MD in different mobile phases were measured and compared with the K values of Si-DO. It was found that the phase ratio of Si-DO varied with mobile phase composition and temperature, as shown by the Φ values: 0.039–0.122 for the methanol/water system and 0.051–0.116 for the acetonitrile/water system; in addition, the a indices were 0.552–0.757 and 0.564–0.674, respectively. The Kdm of MD was closer to the K of Si-DO than those of other surrogate models, including the octanol–water and octane–mobile phase partition coefficients. In addition, the thermodynamic parameters (ΔG°, ΔH°, and ΔS°) of n-alkylbenzenes on Si-DO were negative, indicating a spontaneous and enthalpy-driven separation process. Overall, the phase ratio of rosin-based columns is crucial for accurate thermodynamic analysis and interpretation of the separation mechanism. Finally, the MD surrogate model allows the estimation of phase ratio of Si-DO and other similar columns, providing a novel method for measuring the phase ratio of rosin-based columns and providing a validated concept and methodology for determining the phase ratios of HPLC columns.

Spatial variation and mechanism of the dissolved/particulate organic carbon partitioning of seawater adjacent to the mangrove in Zhangjiang Estuary

Mangrove is one of the most carbon-rich ecosystems in the world. Nevertheless, the understanding of organic carbon partitioning between dissolution and particle in the processes of mangrove outwelling is rather limited, flood–ebb samplings were conducted in January 2021 with 8 sampling sites covering the upper tidal boundary to the mouth in the Zhangjiang Estuary. Water samples were collected to analyze physicochemical properties, dissolved organic carbon (DOC) and particulate organic carbon (POC) contents, and their phase portioning were investigated to analyze the spatial variation between the two phases (dissolve and particle), and their influencing factors. The results showed: (1) DOC was the dominant content with the wide range of 0.48–3.29 mg·L−1, accounting for 77.6% on average; while POC contents were 0.17–1.86 mg·L−1, accounting for 22.4% on average. (2) Silt was dominant component in estuarine suspended sediment, accounting for 68.0% on average; clay accounted for 17.5% of the suspend sediment, and was mainly located in mangrove forest area; sand proportion was the lowest. (3) Both the closed Beijiang sluice and ponds effluents could significantly increase the water organic carbon content, but only ponds effluents changed the phase distribution of organic carbon. In natural processes, a significant positive correlation between particulate and dissolved organic carbon and dissolved oxygen (DO) in the upper estuary (r > 0.9), and a significant negative correlation between particulate and dissolved organic carbon and salinity in the lower estuary (r < −0.7) were observed. The study indicated that DOC was the dominant content, the phase partition coefficients were significantly increased due to the DOC content from pond effluents. In the natural processes, the autotrophic activities by microalgae in the upper estuary and the seawater mixed dilution followed with heterotrophic activities are the important influencing factors.

Extraction of natural colorants using supramolecular solvents composed of Triton X-114 and ionic liquids

The interest for natural colorants from microbial sources has increased in the last few years. However, the extraction of these compounds from complex biomasses/matrices is still a challenge for industrial applications, mainly due to the requirements of biocompatibility, sustainability, and efficiency. With this aim, supramolecular solvents (SUPRAS) composed of nonionic polyethylene glycol tert-octylphenyl ether (TX-114) and various cationic surfactants (n-alkyl-3-methyl imidazolium bromide ([Cnmim]Br, n = 10, 12, 14, 16), and tributyl-tetradecylphosphonium chloride ([P4,4,4,14]Cl) ionic liquids (ILs) and cetyltrimethylammonium bromide (CTAB)) were here studied for the extraction of red polyketides colorants from the fermented broth of Talaromyces amestolkiae. Firstly, the influence of ILs on the SUPRAS phase behavior was determined by measuring the cloud point temperature (TCP) and coarse-grained molecular dynamic (CG-MD) simulations. The results of extraction showed that for all SUPRAS the red colorant preferentially partitioned into the surfactant-rich (bottom) phase (partition coefficients, K > 10) with the highest partition using [C14mim]Br as a co-surfactant (K = 14.69 ± 0.15). The systems studied also allowed high recovery efficiency of all mixed surfactant-based SUPRAS (>70 % of red colorant recovered in a single extraction step) with selective for the separation of the red colorant from the yellow (1.52 ± 0.04) and orange (1.62 ± 0.08) counterparts present in the fermented broth. The novel SUPRAS have demonstrated remarkable potential in extracting red colorants from fermented broth, without requiring harsh operating conditions. As such, these platforms offer an effective means of concentrating and pre-purifying the red colorants, and hold promise for application to other molecules with similar chemical properties.

Metabolic process and spatial partition dynamics of Atrazine in an estuary-to-bay system, Jiaozhou bay

The spatial distributions of atrazine and six types of metabolites in water, suspended particulate sediment (SPS), and surface sediment in an estuary-to-bay system were analyzed. The water distance of metabolites demonstrated that degradation was more active in coastal zone and the Desisopropylatrazine had the shortest half-distance of 1.6 Km from the river mouth. The dechlorination-hydroxylation metabolites were the dominant pollutants in the bay and the Didealkyl-atrazine (DDA), Deisopropylhydroxy-atrazine (DIHA), and Deethylhydroxy-atrazine (DEHA) had higher concentrations in all three mediums. The DDA had the biggest content (6.58 ng/g) in the coastal sediment. The DIHA was the only pollutant had bigger concentration during the transport, and the others continually degraded with smaller value. The spatial distributions of pollutants in sediment had different patterns in water with SPS. The water-particle phase partition coefficient (Kp) analysis indicated that the partition process was more active in the estuary than the bay, and the metabolites had stronger capacity than atrazine. The correlations between Kp with octanol-water partitioning coefficient showed their physic-chemical properties were the important factors for vertical partition between seawater with sediment. The correlations with marine environmental factors demonstrated that the metabolite type was the direct factor for the redistributions during the transport.

Experimental determination of phase ratio of C8 columns employing retention factors and octane-mobile phase partition coefficients of homologous series of linear alkylbenzenes

This work proposes an experimental method for the estimation of the phase ratio of reversed-phase C8 columns by employing the equation log(k)=alog(Kom)+log(Φ), where k is the retention factor, Komis the octane-mobile phase partition coefficient, a is a proportionality constant and Φ is the phase ratio (defined as volume ratio of the stationary phase to the mobile phase). The immiscible liquid octane and mobile phase are chosen as the surrogate model for the C8 stationary phase and mobile phase of the chromatographic system. The octane-mobile phase is used for measuring the partition coefficient Kom of six compounds of the homologous series of linear alkylbenzenes, viz. benzene, toluene, ethylbenzene, propylbenzene, butylbenzene and pentylbenzene. The distribution of a compound between the octane and mobile phase is proposed to simulate the partitioning process in the chromatography. The retention factor k of each compound is measured using the same mobile phase for two C8 columns (Zorbax Eclipse XDB-C8 and Symmetry C8). The set of data of k and Kom is fitted to the above linear equation to give the best-fit values of a and log(Φ) for each column and various mobile phase compositions (methanol-water or acetonitrile-water). The regression analyses have coefficients of determination r2 > 0.992. This observed linear relationship can therefore be expressed as k=KomaΦ. The experimental values of Φ for the C8 columns are in the range of 0.206 to 0.842, with a from 0.544 to 0.811, respectively.

5-Hydroxymethylfurfural Synthesis from Monosaccharides by a Biphasic Reaction-Extraction System Using a Microreactor and Extractor.

5-Hydroxymethylfurfural (HMF) was synthesized from monosaccharides by a biphasic reaction system using a microreactor. The biphasic reaction system realized an immediate extraction and stabilization of product HMF, which further degrades under the reaction conditions. Segmented flow was utilized for an efficient reaction–extraction tool. The effect of extraction ability was evaluated based on the extraction phase/reaction phase partition coefficient of HMF. A Lewis acid catalyst was introduced to overcome the obstacle of the reaction, which was clarified as the isomerization of glucose to fructose, and improved the HMF yield to 85 mol % under the condition of T = 180 °C and τ = 47 min. The recovery of the product HMF was also examined using a constructed microextraction system, and HMF was selectively recovered from the extraction phase.

The Study of Stability and Location of Chloramphenicol in Newly Formed Microemulsion Based Ocular Drug Delivery System

Microemulsions (MEs) are homogeneous, optically clear and thermodynamically stable systems intended to increase the bioavailbility, solubility, and entrapment of drugs. Anew system of oil-in-water MEs was formulated for the entrapment of chloramphenicol, consisting of isopropyl myristate/Tween 60/80 with short-chain alcohol and phosphate buffer (pH 7). The 1H NMR spectroscopy was used for investigation of the drug location in formulation. The drug is entrapped in a hydrophilic shell of ME, which consists of oxyethylene groups. It was revealed by 1H NMR study that the drug stability increases due to its screening from bulk water. The formulated MEs were evaluated for the phase composition, pH, refractive index, conductivity, surface tension, partition coefficient, and viscosity. These characteristics suggested that the optimized MEs were stable and optically clear and could be used as an efficient ocular drug carrier.

Noninvasive PET Imaging of CDK4/6 Activation in Breast Cancer.

The cell cycle is a progression of 4 distinct phases (G1, S, G2, and M), with various cycle proteins being essential in regulating this process. We aimed to develop a radiolabeled cyclin-dependent kinase 4/6 (CDK4/6) inhibitor for breast cancer imaging. Our transfluorinated analog (18F-CDKi) was evaluated and validated as a novel PET imaging agent to quantify CDK4/6 expression in estrogen receptor (ER)-positive human epidermal growth factor receptor 2 (HER2)-negative breast cancer. Methods:18F-CDKi was synthesized and assayed against CDK4/6 kinases. 18F-CDKi was prepared with a 2-step automated synthetic strategy that yielded the final product with remarkable purity and molar activity. In vitro and in vivo biologic specificity was assessed in a MCF-7 cell line and in mice bearing MCF-7 breast tumors. Nonradioactive palbociclib was used as a blocking agent to investigate the binding specificity and selectivity of 18F-CDKi. Results:18F-CDKi was obtained with an overall radiochemical uncorrected yield of 15% and radiochemical purity higher than 98%. The total time from the start of synthesis to the final injectable formulated tracer is 70 min. The retention time reported for 18F-CDKi and 19F-CDKi is 27.4 min as demonstrated by coinjection with 19F-CDKi in a high-pressure liquid chromatograph. In vivo blood half-life (weighted, 7.03 min) and octanol/water phase partition coefficient (1.91 ± 0.24) showed a mainly lipophilic behavior. 18F-CDKi is stable in vitro and in vivo (>98% at 4 h after injection) and maintained its potent targeting affinity to CDK4/6. Cellular uptake experiments performed on the MCF-7 breast cancer cell line (ER-positive and HER2-negative) demonstrated specific uptake with a maximum intracellular concentration of about 65% as early as 10 min after incubation. The tracer uptake was reduced to less than 5% when cells were coincubated with a molar excess of palbociclib. In vivo imaging and ex vivo biodistribution of ER-positive, HER2-negative MCF-7 breast cancer models showed a specific uptake of approximately 4% injected dose/g of tumor (reduced to ∼0.3% with a 50-fold excess of cold palbociclib). A comprehensive biodistribution analysis also revealed a significantly lower activation of CDK4/6 in nontargeting organs. Conclusion:18F-CDKi represents the first 18F PET CDK4/6 imaging agent and a promising imaging agent for ER-positive, HER2-negative breast cancer.

A robotic platform to screen aqueous two-phase systems for overcoming inhibition in enzymatic reactions

Aqueous two-phase systems (ATPS) can be applied to enzymatic reactions that are affected by product inhibition. In the biorefinery context, sugars inhibit the cellulolytic enzymes in charge of converting the biomass. Here, we present a strategy to select an ATPS (formed by polymer and salt) that can separate sugar and enzymes. This automated and miniaturized method is able to determine phase diagrams and partition coefficients of solutes in these. Tailored approaches to quantify the solutes are presented, taking into account the limitations of techniques that can be applied with ATPS due to the interference of phase forming components with the analytics. The developed high-throughput (HT) platform identifies suitable phase forming components and the tie line of operation. This fast methodology proposes to screen up to six different polymer-salt systems in eight days and supplies the results to understand the influence of sugar and protein concentrations on their partition coefficients.

Betacyanins extraction from Hylocereus polyrhizus using alcohol/salt-based liquid biphasic partitioning system and antioxidant activity evaluation

ABSTRACTBetacyanins have gained increasing interest as natural food dye because of their health-promoting effects. This study investigated the betacyanins extraction from peel and flesh of red–purple pitaya using ethanol/K2HPO4-based liquid biphasic partitioning system (LBPS) by optimised concentrations of ethanol, K2HPO4, NaCl and crude. Overall, the highest values of betacyanins concentration in alcohol-rich top phase (Ct), phase volume ratio (Vr) and partition coefficient (K) of betacyanins that represented an optimum betacyanins extraction from the peel (98.080%, 1.667 and 51.097, respectively) and flesh (96.256%, 2.167 and 25.764, respectively) were achieved. Lastly, conventional solvent extractions, colour characterisation and antioxidant activity evaluation were conducted.

Partitioning performance of molybdenum in poly (ethylene glycol) + sodium sulfate + water aqueous two-phase systems

Partition performance of molybdenum (VI) by aqueous two-phase systems (ATPSs) composed of poly (ethylene glycol) (PEG1000, PEG2000 and PEG4000)+sodium sulfate+H2O without any extractant was systematically studied. Response surface optimization method was applied to study the effects of different factors such as, the type and concentration of PEG, sodium sulfate concentration, molybdenum concentration and temperature on the phase volume ratio, partition coefficient and extraction rate of molybdenum. The experimental results showed that the phase volume ratio changes with all four parameters, resulting from hydration of sodium sulfate, dehydration of increasing temperature and replace of molybdenum to water. The partitioning coefficient and extraction rate of molybdenum increases as increasing sodium sulfate concentration being of hydration of sodium sulfate, and also increases with increasing temperature, indicating that the transfer process of molybdenum from the salt-rich phase to the PEG-rich phase is endothermic. With the increase of PEG molecular weight (PEG1000, PEG2000 and PEG4000), the phase volume ratio decreases and partitioning coefficient and extraction rate of molybdenum goes up. The extraction mechanism can be deduced that molybdenum was extracted into PEG-rich phase by electrostatic attraction between polymolybdate anion and protonated COC bond in PEG molecule due to relatively high hydrophobicity of polymolybdate anion under the salting-out effect of phase-forming sodium sulfate by the change of initial and equilibrium pH in aqueous phase, FTIR and Raman spectrum analysis. A better result on extracting and separating molybdenum was achieved by applying the proposed method to the leaching liquor of low-grade molybdenite concentrate.

Bacteriocin partitioning from a clarified fermentation broth of Lactobacillus plantarum ST16Pa in aqueous two-phase systems with sodium sulfate and choline-based salts as additives

Abstract The partitioning of bacteriocin, a promising alternative to chemical preservatives, in a novel inexpensive and stable aqueous two-phase system (ATPS) comprising poly(ethylene glycol) (PEG) and sodium polyacrylate (NaPA) was studied. The ATPS was generated by mixing both polymers with Na2SO4 or choline chloride ([Ch]Cl) and a bacteriocin extract from the fermented broth of Lactobacillus plantarum ST16Pa. Bacteriocin showed stability at different pH values (3.0–8.0) and temperatures (50–80 °C), as well as in the presence of ATPS components. Hydrophobic and electrostatic interactions were found to be the major driving forces for bacteriocin partitioning. The peptide partitioned preferentially to the PEG-rich phase (partition coefficient, KBact > 1). However, the highest partition coefficient was achieved in the polymeric-based ATPS using [Ch]Cl as additive, as follows: 8 wt% PEG 10,000 g/mol/8 wt% NaPA 8,000 g/mol/0.5 M [Ch]Cl, resulting in a KBact equal to 32. Moreover, these conditions promoted high selectivity (S = 62.7), since the greater part of total proteins partitioned into the NaPA-rich phase (Kprot = 0.51). In conclusion, ATPS composed of PEG/NaPA using choline-based salts as additive can be considered mainly as a first step for bacteriocin extraction from fermented broth by applying low polymer content and mild conditions.

Uncertain Henry's law constants compromise equilibrium partitioning calculations of atmospheric oxidation products

Abstract. Gas–particle partitioning governs the distribution, removal, and transport of organic compounds in the atmosphere and the formation of secondary organic aerosol (SOA). The large variety of atmospheric species and their wide range of properties make predicting this partitioning equilibrium challenging. Here we expand on earlier work and predict gas–organic and gas–aqueous phase partitioning coefficients for 3414 atmospherically relevant molecules using COSMOtherm, SPARC Performs Automated Reasoning in Chemistry (SPARC), and poly-parameter linear free-energy relationships. The Master Chemical Mechanism generated the structures by oxidizing primary emitted volatile organic compounds. Predictions for gas–organic phase partitioning coefficients (KWIOM/G) by different methods are on average within 1 order of magnitude of each other, irrespective of the numbers of functional groups, except for predictions by COSMOtherm and SPARC for compounds with more than three functional groups, which have a slightly higher discrepancy. Discrepancies between predictions of gas–aqueous partitioning (KW/G) are much larger and increase with the number of functional groups in the molecule. In particular, COSMOtherm often predicts much lower KW/G for highly functionalized compounds than the other methods. While the quantum-chemistry-based COSMOtherm accounts for the influence of intra-molecular interactions on conformation, highly functionalized molecules likely fall outside of the applicability domain of the other techniques, which at least in part rely on empirical data for calibration. Further analysis suggests that atmospheric phase distribution calculations are sensitive to the partitioning coefficient estimation method, in particular to the estimated value of KW/G. The large uncertainty in KW/G predictions for highly functionalized organic compounds needs to be resolved to improve the quantitative treatment of SOA formation.

Evaluation of the Capability of Ionic Liquid-Amino Acid Aqueous Systems for the Formation of Aqueous Biphasic Systems and Their Applications in Extraction.

To obtain further experimental evidence for a better understanding of the molecular mechanisms responsible for the soluting-out effect phenomena in ternary systems composed of an ionic liquid (IL), amino acid, and water, systematic studies on the vapor-liquid, liquid-liquid, and solid-liquid equilibrium behavior of aqueous solutions of several ILs were carried out in the presence of a range of amino acids. Water activities for binary and ternary aqueous solutions containing 1-butyl-3-methylimidazolium chloride, [C4mim]Cl, 1-hexyl-3-methylimidazolium chloride, [C6mim]Cl, 1-butyl-3-methyl-imidazolium trifluoromethanesulfonate, [C4mim][CF3SO3], l-Ser, Gly, Ala, and l-Pro were measured using both vapor pressure osmometry and isopiestic methods. All of the ternary IL + amino acid + water systems show negative deviations from semi-ideal behavior and therefore soluting-out effects have been observed in these systems. In the case of the [C4mim][CF3SO3] + amino acids aqueous systems, the IL is soluted-out by the amino acids and the soluting-out effect appears by aqueous biphasic system formation. For these systems, the phase diagram and partition coefficient of caffeine were measured at 298.15 K. However, for the [C4mim]Cl and [C6mim]Cl containing systems, the amino acids are soluted-out by the ILs and the soluting-out effect appears by precipitation of the amino acids from the solution, and the solubilities of the amino acids in the aqueous solutions decrease in the presence of [C4mim]Cl and [C6mim]Cl.

Prediction and mechanism elucidation of analyte retention on phospholipid stationary phases (IAM-HPLC) by in silico calculated physico-chemical descriptors

The present study proposes a method for an in silico calculation of phospholipophilicity. Phospholipophilicity is intended as the measure of analyte affinity for phospholipids; it is currently assessed by HPLC measures of analyte retention on phosphatidylcholine-like stationary phases (IAM – Immobilized Artificial Membrane) resulting in log kWIAM values. Due to the amphipathic and electrically charged nature of phospholipids, retention on these stationary phases results from complex mechanisms, being affected not only by lipophilicity (as measured by n-octanol/aqueous phase partition coefficients, log P) but also by the occurrence of polar and/or electrostatic intermolecular interaction forces. Differently from log P, to date no method has been proposed for in silico calculation of log kWIAM.The study is aimed both at shedding new light into the retention mechanism on IAM stationary phases and at offering a high-throughput method to achieve such values. A wide set of physico-chemical and topological properties were taken into account, yielding a robust final model including four in silico calculated parameters (lipophilicity, hydrophilic/lipophilic balance, molecular size, and molecule flexibility). The here presented model was based on the analysis of 205 experimentally determined values, taken from the literature and measured by a single research group to minimize the interlaboratory variability; such model is able to predict phospholipophilicity values on both the two IAM stationary phases to date marketed, i.e. IAM.PC.MG and IAM.PC.DD2, with a fairly good degree (r2=0.85) of accuracy.The present work allowed the development of a free on-line service aimed at calculating log kWIAM values of any molecule included in the PubChem database, which is freely available at http://nova.disfarm.unimi.it/logkwiam.htm.

Multiphase partitioning and risk assessment of endocrine-disrupting chemicals in the Pearl River, China.

Multiphase partitioning of endocrine-disrupting chemicals (EDCs) in the Pearl River (China) were investigated. The colloidal concentrations for 4-tert-octylphenol, 4-nonylphenol, bisphenol A (BPA), and estrone (E1) were in the ranges of 0.2 ng/L to 0.8 ng/L, 23.2 ng/L to 108 ng/L, 2.3 ng/L to 97.6 ng/L, and not detectable (nd) to 0.32 ng/L, respectively; for truly dissolved concentrations, the ranges were 0.5 ng/L to 5.4 ng/L, 39 ng/L to 319 ng/L, 13.7 ng/L to 91.2 ng/L, and nd to 1.2 ng/L, respectively. Positive correlations of EDCs with colloidal organic carbon (COC) were observed. The in situ COC normalized partitioning coefficients (log KCOC ) for 4-tert-octylphenol (5.35 ± 0.42), 4-nonylphenol (5.69 ± 0.50), and BPA (5.51 ± 0.77) were within the ranges reported by other studies, whereas they were 1 to 2 orders of magnitude higher than their particulate/truly dissolved phase partition coefficients (log KOCint), revealing much strong sorption of EDCs by aquatic colloids. Moreover, colloid-bound percentages of 4-tert-octylphenol, 4-nonylphenol, and BPA ranged, respectively, from 6.9% to 36.4%, from 16.7% to 63.1%, and from 3.6% to 52.4%; their estimated mass fractions were 0.29 ± 0.21, 0.38 ± 0.26, and 0.39 ± 0.33, respectively. Obviously the colloid-bound fractions are significant. Furthermore, a medium risk of estrogenic effects was estimated from the truly dissolved concentrations of EDCs in the Pearl River, which was lower than the estimated high risk according to the conventionally dissolved concentrations. It is suggested that the presence of colloids be incorporated into future water quality prediction and ecological risk assessment. Environ Toxicol Chem 2016;35:2474-2482. © 2016 SETAC.

Green, Aqueous Two-Phase Systems Based on Cholinium Aminoate Ionic Liquids with Tunable Hydrophobicity and Charge Density

Cholinium-based ionic liquids made of aminoate anions ([Ch][AA] ILs) have been proven to have low toxicity and to be readily biodegradable. This class of ILs has great potential as a novel phase-forming component for aqueous two-phase system (ATPS) used in protein separation. In this study, environmentally benign ATPSs were prepared by using a series of [Ch][AA] ILs (where [AA] = lysinate, β-alaninate, glycinate, serinate) with a thermo-separable polypropylene glycol 400 (PPG 400). These [AA] anion components differ in both hydrophobicity and acid/base behavior, allowing a tunable response to the pH of the ATPS. By using the effective excluded volume theory, the phase-separation abilities of the different [Ch][AA]-based ATPSs were determined, and the trends showed good agreement with the [AA] anion hydration capacities. The partition behavior of a model protein, i.e., bovine serum albumin (BSA), was investigated by measuring the IL-rich (bottom) phase extraction efficiency and partition coefficient. The r...

Activation of Single-Component Nickel(II) Polyethylene Catalysts via Phase Transfer of Fluorous Phosphine Ligands.

The nickel salicylaldiminato phosphine complexes [1,2,3-C6H3(9-anthracenyl)O(CH═N(2,6-C6H3(iPr)2)]Ni(Me)[P(4-C6H4R)3] (4; R = a, (CH2)2Rf8; b, (CH2)3Rf8; c, H (Rf8 = (CF2)7CF3)) are prepared from the corresponding phosphines 3a-c and nickel NCMe adduct (46-68%). These are applied as catalysts for ethylene polymerization in toluene and fluorous/toluene liquid/liquid biphasic mixtures. Under the latter conditions, the fluorous phosphines 3a,b that must dissociate to generate the active catalyst migrate to the fluorous phase (partition coefficients 97.5:2.5 and 66.6:33.4 vs <0.5:>99.5 for 4a,b). Catalysts 4a,b show marked accelerations under biphasic conditions, but 4c (which has a lipophilic phosphine ligand) does not. Under all conditions, 4a,b are faster catalysts than the Ni(Ph)(PPh3) analogue, a previously reported benchmark.

Temperature dependencies of Henry’s law constants for different plant sesquiterpenes

Sesquiterpenes are plant-produced hydrocarbons with important ecological functions in plant-to-plant and plant-to-insect communication, but due to their high reactivity they can also play a significant role in atmospheric chemistry. So far, there is little information of gas/liquid phase partition coefficients (Henry’s law constants) and their temperature dependencies for sesquiterpenes, but this information is needed for quantitative simulation of the release of sesquiterpenes from plants and modeling atmospheric reactions in different phases. In this study, we estimated Henry’s law constants (Hpc) and their temperature responses for 12 key plant sesquiterpenes with varying structure (aliphatic, mono-, bi- and tricyclic sesquiterpenes). At 25°C, Henry’s law constants varied 1.4-fold among different sesquiterpenes, and the values were within the range previously observed for monocyclic monoterpenes. Hpc of sesquiterpenes exhibited a high rate of increase, on average ca. 1.5-fold with a 10°C increase in temperature (Q10). The values of Q10 varied 1.2-fold among different sesquiterpenes. Overall, these data demonstrate moderately high variation in Hpc values and Hpc temperature responses among different sesquiterpenes. We argue that these variations can importantly alter the emission kinetics of sesquiterpenes from plants.