Wide Range Of Polarities Research Articles

Development and validation of a stability-indicating HPLC method for topiramate using a mixed-mode column and charged aerosol detector.

The analysis of topiramate in the presence of its main degradation products is challenging due to the absence of chromophore moieties and their wide range of polarity. Mixed-mode chromatography has been used in such cases because it combines two or more modes of separation. Charged aerosol detector is also an alternative since its detection is independent of optical properties and analyte ionization. This study is aimed to develop and validate two new stability-indicating methods by high-performance liquid chromatography for the main degradation products of topiramate using mixed-mode chromatography and a charged aerosol detector. Method 1 employed an Acclaim Trinity P1® column (3.0mm×150mm, 2.7μm) with a mobile phase comprising of 80% ammonium acetate buffer (20mM, pH 4.0) and 20% methanol at a flow rate of 0.5mL/min at 35°C. Method 2 utilized a C18 Acclaim 120® column (4.6mm×250mm; 5μm) with ACN/water (50:50) at a flow rate of 0.6mL/min at 50°C. Validation of the two methods demonstrated excellent performance with respect to linearity, precision, accuracy, and selectivity. The limits of detection for topiramate, fructose, sulfate, sulfamate, and compound A were 2.97, 12.08, 4.02, 13.91, and 3.94μg/mL, respectively.

Extraction optimization, total phenolic, flavonoid contents, HPLC-DAD analysis and diverse pharmacological evaluations of Dysphania ambrosioides (L.) Mosyakin & Clemants

The present study aims to evaluate phytochemical and pharmacological potentials of Dysphania ambrosioides (L.) Mosyakin & Clemants previously known as Chenopodium ambrosioides L. Extraction was carried out using 14 solvents with wide range of polarity to find out the best solvent system for each bioactivity. Total phenolic and flavonoids contents were measured colorimetrically and polyphenolics were quantified via HPLC-DAD analysis. The samples were screened for inhibitory potentials against free radicals, leishmania, cancer cell lines, protein kinase, α-Amylase enzymes and microbial strains. Among all solvents, maximum percentage of extract was recovered from methanol-water fraction of leaves. HPLC analysis exhibited the presence of rutin, myricetin and quercetin. In DPPH assay, methanolic leaf extract exhibited IC50 value of 130.7 ± 0.57 μg/mL. Considerable α-amylase inhibitory, cytotoxic, leishmanicidal and antimicrobial potentials were exhibited by plant samples. D. ambrosioides revealed significant antioxidant, cytotoxic, antimicrobial and anti-diabetic potentials and thus warrant further detailed studies to find novel drugs.

Theoretical insight into the effect of solvent polarity on the formation and morphology of 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (CL-20)/2,4,6-trinitro-toluene(TNT) cocrystal explosive

Abstract Molecular dynamics simulations were employed to study the effect of solvents of varying polarity on the formation and morphology of 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (CL-20)/2,4,6-trinitro-toluene(TNT) cocrystal explosive. Six solvents, i.e. n-heptane, toluene, ethanol, acetonitrile, methanol and dimethyl sulfoxide with a wide range of polarity were used. The cocrystal morphology was predicted by Growth Morphology Model. The surface conformation and polarity were used to estimate the molecular parking of cocrystal surface. The interaction energies and binding energies were used to determine the influence of solvent properties (i.e. polarity, permittivity, molecule weight and vapor pressure) on the formation and morphology. The results indicate that the predicted morphology of CL-20/TNT cocrystal is dominated by the (0 0 2), (1 1 1), (0 2 0) and (0 2 1) in vacuum. CL-20/TNT cocrystal is easier to form in moderately polar solvents, that is, ethanol and acetonitrile. CL-20 molecules are more inclined to interact with TNT in (1 1 1) and (0 2 1) CL-20/TNT-solvent interfaces than in (0 0 2) and (0 2 0) interfaces. The predicted cocrystal morphology is in good agreement with the experimental morphology in ethonal solution. In addition, radial distribution function (RDF) analyses further proved the existence of interactions between the cocrystal faces and solvents.

Improving the On-Line Extraction of Polar Compounds by IT-SPME with Silica Nanoparticles Modified Phases

In the present work the extraction efficiency of in-tube solid-phase microextraction (IT-SPME) for polar herbicides has been evaluated using extractive capillaries coated with different polymeric sorbents. For this purpose, aqueous solutions of herbicides with a wide range of polarities, including some highly polar compounds (log Kow < 1), have been directly processed by IT-SPME coupled on-line to capillary liquid chromatography with UV-diode array detection. For extraction, commercially available capillary columns coated with polydimethylsiloxane (PDMS) and polyetilenglicol (PEG)-based phases have been used, and the results have been compared with those obtained with a synthesized tetraethyl orthosilicate (TEOS)-trimethoxyethylsilane (MTEOS) polymer, as well as the same polymer reinforced with silica nanoparticles (SiO2 NPs). The SiO2 NPs functionalized TEOS-MTEOS coating provided the best results for most herbicides, especially for the most polar compounds. On the basis of the results obtained, conditions for the quantification of the herbicides tested are described using a SiO2 NPs reinforced TEOS-MTEOS coated capillary. The proposed method provided satisfactory linearity up to concentrations of 200 μg/L. The precision was also suitable, with relative standard deviations (RSDs) values ≤9% (n = 3), and the limits of detection (LODs) were within the 0.5–7.5 µg/L range. The method has been applied to different water samples and the extract obtained from an agricultural soil.

Disk solid-phase extraction of multi-class pharmaceutical residues in tap water and hospital wastewater, prior to ultra-performance liquid chromatographic-tandem mass spectrometry (UPLC-MS/MS) analyses.

In this work, a new clean-up and pre-concentration method based on disk solid-phase extraction (SPE) was developed to determine multi-class pharmaceutical residues covering a wide range of polarities (log Kow values from −0.5 to 5.1) in water systems, prior to ultra-performance liquid chromatographic-tandem mass spectrometry (UPLC-MS/MS) analyses. Electrospray ionisation in positive and negative modes was used for the simultaneous determination of both acidic and basic pharmaceuticals. The performances of disk SPE and cartridge SPE were compared. The targeted pharmaceutical compounds list included bronchodilators, antidiabetic drugs, antihypertensive drugs, a lipid-lowering agent, analgesics, and anti-inflammatory drugs. Based on our results, the disk SPE demonstrated a higher sensitivity and recovery value and less analysis time as compared to the cartridge SPE method. The limits of detection (LOD) for the new method ranged from 0.02–3.2 ng L−1, 0.02–3.1 ng L−1 and 0.02–4.7 ng L−1 for tap, effluent and influent wastewater, respectively. The method's absolute recovery values ranged from 70% to 122% for tap water, 62% to 121% for effluent wastewater and 62% to 121% for influent wastewater, except for metformin in which the absolute recovery value was approximately 48% for all samples. Intra-day precision for tap water, effluent and influent wastewater ranged from 3–12%, 4–9% and 2–8%, respectively. The method developed was applied for the determination of targeted pharmaceuticals in tap, effluent, and influent wastewater from one hospital treatment plant in Malaysia. The results revealed that the highest concentrations of certain pharmaceuticals were up to 49 424 ng L−1 (acetaminophen) and 1763 ng L−1 (caffeine) in the influent and effluent wastewater, respectively. The results also showed a variation in the treatment efficiencies for the hospital treatment plant from one compound to another. Nevertheless, the removal efficiencies ranged from 0–99%.

Comparison of salting-out and sugaring-out liquid–liquid extraction methods for the partition of 10-hydroxy-2-decenoic acid in royal jelly and their co-extracted protein content

Homogeneous liquid–liquid extraction (h-LLE) has been receiving considerable attention as a sample preparation method due to its simple and fast partition of compounds with a wide range of polarities. To better understand the differences between the two h-LLE extraction approaches, salting-out assisted liquid–liquid extraction (SALLE) and sugaring-out assisted liquid–liquid extraction (SULLE), have been compared for the partition of 10-hydroxy-2-decenoic acid (10-HDA) from royal jelly, and for the co-extraction of proteins. Effects of the amount of phase partition agents and the concentration of acetonitrile (ACN) on the h-LLE were discussed. Results showed that partition efficiency of 10-HDA depends on the phase ratio in both SALLE and SULLE. Though the partition triggered by NaCl and glucose is less efficient than MgSO4 in the 50% (v/v) ACN-water mixture, their extraction yields can be improved to be similar with that in MgSO4 SALLE by increasing the initial concentration of ACN in the ACN-water mixture. The content of co-extracted protein was correlated with water concentration in the obtained upper phase. MgSO4 showed the largest protein co-extraction at the low concentration of salt. Glucose exhibited a large protein co-extraction in the high phase ratio condition. Furthermore, NaCl with high initial ACN concentration is recommended because it produced high extraction yield for 10-HDA and the lowest amount of co-extracted protein. These observations would be valuable for the sample preparation of royal jelly.

Vapor Sorption and Solvatochromism in a Metal–Organic Framework of an Asymmetric Pyridylcarboxylate

Two new metal–organic frameworks (MOFs) of cobalt(II) and 3-(4-pyridyl)benzoate (34pba) were prepared concomitantly under solvothermal conditions. Using dimethylformamide (DMF) as solvent, {[Co(34pba)2(H2O)]·1/2DMF·H2O}n, 1, can be prepared as a pure phase in the presence of the templating molecules arginine or proline, neither of which is incorporated in the resulting structure. {[Co(34pba)2]·2DMA}n, 2, (where DMA is dimethylacetamide) has the same framework formula as two previously reported MOFs and represents a third in this series of structural isomers. The activated phase of 1, 1d absorbs a number of solvent vapors, across a wide range of polarities, with accompanying phase changes and solvatochromic responses. The facile exchange of guest species within the framework of 1d is explained by the low activation energy (59–69 kJ mol–1) for the desorption of water from 1d·H2O.

Comprehensive profiling of minor tyrosinase inhibitors from Gastrodia elata using an off-line hyphenation of ultrafiltration, high-speed countercurrent chromatography, and high-performance liquid chromatography

In the present study, a novel hyphenation of ultrafiltration (UF), high-speed countercurrent chromatography (HSCCC), and high-performance liquid chromatography (HPLC) was developed for comprehensive profiling and characterization of the minor tyrosinase inhibitors from Gastrodia elata (GE). A small quantity of GE extract was first fractionated by HSCCC, using elution solvents with a wide range of polarities to enrich minor compounds; then, the fractions were profiled by UF-HPLC to generate a comprehensive 2D chromatogram of the distribution of bioactive components. To determine the binding affinities of these bioactive components, the binding degree (BD%) was calculated by peak area reduction, in which a higher BD% indicates a higher binding affinity to tyrosinase. Among the 212 metabolites, 49 were identified as tyrosinase ligands, 17 of which showed high binding affinity. According to the 2D chromatogram, these 17 candidates were isolated by semiprep-HPLC for characterization of their structure using off-line hyphenated ultraviolet (UV), electron ionized mass spectrometry (EIMS), proton nuclear magnetic resonance (1H NMR). Their activities were further validated by functional assays. In conclusion, the approach developed here can comprehensively identify both major and minor bioactive constituents from natural products, and provide meaningful suggestions to direct further research. Compared to conventional approaches, this approach, developed by hyphenating several techniques, is a highly efficient means for comprehensive profiling of potent minor compounds extracted from natural products.

Going beyond the standard line tension: Size-dependent contact angles of water nanodroplets

The dependence of the contact angle on the size of a nanoscopic droplet residing on a flat substrate is traditionally ascribed solely to line tension. Other contributions, stemming from the droplet geometry dependence of the surface tension and line tension, are typically ignored. Here, we perform molecular dynamics simulations of water droplets of cylindrical morphology on surfaces of a wide range of polarities. In the cylindrical geometry, where the line tension is not operative directly, we find significant contact angle dependence on the droplet size. The effect is most pronounced on hydrophilic surfaces, with the contact angle increase of up to 10° with a decreasing droplet size. On hydrophobic surfaces, the trend is reversed and considerably weaker. Our analysis suggests that these effects can be attributed to the Tolman correction due to the curved water-vapor interface and to a generalized line tension that possesses a contact angle dependence. The latter is operative also in the cylindrical geometry and yields a comparable contribution to the contact angle as the line tension itself in case of spherical droplets.

Multiresidue determination and potential risks of emerging pesticides in aquatic products from Northeast China by LC–MS/MS

A simple method for determining 33 pesticides with a wide polarity range (logKow 0.6–4.5) in aquatic products was developed based on LC–MS/MS. The target analytes included three types of widely used pesticides: insecticides, fungicides and herbicides. Based on the optimization of ultrasonic assisted extraction and GPC clean-up procedures, the matrix effect, extraction recoveries and LOD were improved distinctively. LOQ of this method was below 0.5ng/g for all pesticides, which is superior to values in the literature, and the matrix effect was reduced effectively (−14.7% to 7.5%). The method was successfully applied to investigate the pesticide residue levels of twenty-five samples including seven common kinds of fishes from Northeast China. The results showed that all targeted pesticides were present in the fish samples; however, their levels were low, except for atrazine, linuron, ethoprophos, tetrachlorvinphos, acetochlor and fenthion. Atrazine and linuron caught our attention because the concentrations of atrazine in fish samples from Liaoning province were in the range of 0.5–8ng/g (w/w) with mean concentration of 2.3ng/g, which were far above those of other pesticides. The levels of linuron were in the range of 0.6–6ng/g (mean concentration 2.8ng/g), which were the highest among all targeted pesticides in the Inner Mongolia. This is the first systematic investigation on the characteristics and levels of these pesticides in aquatic products from northeast China. Considering their toxicity and bioaccumulation, the potential risk of atrazine and linuron from consuming aquatic products should be paid more attention.

Salting-out-enhanced ionic liquid microextraction with a dual-role solvent for simultaneous determination of trace pollutants with a wide polarity range in aqueous samples.

In real aquatic environments, many occupational pollutants with a wide range of polarities coexist at nanogram to milligram per liter levels. Most reported microextraction methods focus on extracting compounds with similar properties (e.g., polarity or specific functional groups). Herein, we developed a salting-out-enhanced ionic liquid microextraction based on a dual-role solvent (SILM-DS) for simultaneous detection of tetracycline, doxycycline, bisphenol A, triclosan, and methyltriclosan, with log K ow ranging from -1.32 to 5.40 in complex milk and environmental water matrices. The disperser in the ionic-liquid-based dispersive liquid-liquid microextraction was converted to the extraction solvent in the subsequent salting-out-assisted microextraction procedures, and thus a single solvent performed a dual role as both extractant and disperser in the SILM-DS process. Acetonitrile was selected as the dual-role solvent because of its strong affinity for both ionic liquids and water, as well as the extractant in the salting-out step. Optimized experimental conditions were 115 μL [C8MIM][PF6] as extractor, 1200 μL acetonitrile as dual-role solvent, pH 2.0, 5.0 min ultrasound extraction time, 3.0 g Na2SO4, and 3.0 min vortex extraction time. Under optimized conditions, the recoveries of the five pollutants ranged from 74.5 to 106.9%, and their LODs were 0.12-0.75 μg kg-1 in milk samples and 0.11-0.79 μg L-1 in environmental waters. Experimental precision based on relative standard deviation was 1.4-6.4% for intraday and 2.3-6.5% for interday analyses. Compared with previous methods, the prominent advantages of the newly developed method are simultaneous determination of pollutants with a wide range of polarities and a substantially reduced workload for ordinary environmental monitoring and food tests. Therefore, the new method has great application potential for simultaneous determination of trace pollutants with strongly contrasting polarities in several analytical fields. Graphical Abstract A salting-out-enhanced ionic liquid microextraction based on a dual-role solvent (SILM-DS) was developed for simultaneous detection of tetracycline, doxycycline, bisphenol A, triclosan and methyltriclosan, with log K ow ranging from -1.32 to 5.40. The novelty of SILM-DS method lies in (1) simultaneous quantification of pollutants with contrasting polarity; (2) microextraction based on a dual-role solvent (as a disperser and extractant); (3) giving high recoveries for analytes with a wide range of polarities; and (4) reducing workload for ordinary environmental monitoring and food tests.

Comparison of fully wettable RPLC stationary phases for LC-MS-based cellular metabolomics.

Reversed-phase LC combined with high-resolution mass spectrometry (HRMS) is one of the most popular methods for cellular metabolomics studies. Due to the difficulties in analyzing a wide range of polarities encountered in the metabolome, 100%-wettable reversed-phase materials are frequently used to maximize metabolome coverage within a single analysis. Packed with silica-based sub-3μm diameter particles, these columns allow high separation efficiency and offer a reasonable compromise for metabolome coverage within a single analysis. While direct performance comparison can be made using classical chromatographic characterization approaches, a comprehensive assessment of the column's performance for cellular metabolomics requires use of a full LC-HRMS workflow in order to reflect realistic study conditions used for cellular metabolomics. In this study, a comparison of several reversed-phase LC columns for metabolome analysis using such a dedicated workflow is presented. All columns were tested under the same analytical conditions on an LC-TOF-MS platform using a variety of authentic metabolite standards and biotechnologically relevant yeast cell extracts. Data on total workflow performance including retention behavior, peak capacity, coverage, and molecular feature extraction repeatability from these columns are presented with consideration for both nontargeted screening and differential metabolomics workflows using authentic standards and Pichia pastoris cell extract samples.

Evaluation of the effect of ionic liquids as adjuvants in polymer-based aqueous biphasic systems using biomolecules as molecular probes

Aqueous biphasic systems (ABS) have been largely investigated for the extraction, separation and/or purification of biomolecules. Recently, the use of ionic liquids (ILs) as additives in conventional polymer-based ABS was proposed to overcome the limited range of polarities of the coexisting phases. However, the impact of ILs on the partitioning of biomolecules on IL additivated ABS is not universal and is still poorly understood. Aiming at obtaining additional insights on this matter, the effects of the chemical structure of the IL, tie-line length (TLL) and biomolecule nature upon the partition of a series of model biomolecules were investigated. For this purpose, ternary ABS (composed of polyethylene glycol (PEG) 400, citrate buffer at pH 7.0, and water), and several quaternary ABS (composed of PEG 400, citrate buffer at pH 7.0, water and ILs at 5 wt%), were prepared using different chloride-based ILs ([C4mim]Cl, [C4mpyr]Cl, [C4mpip]Cl, [P4444]Cl and [N4444]Cl). The partition of a wide range of biomolecules in these systems (gallic acid, vanillic acid, eugenol, nicotine, caffeine, l-tryptophan, l-phenylalanine and l-tyrosine), used here as molecular probes, was studied. These solutes were chosen due to their wide range of polarities. The results obtained support the concept that ILs, when used as adjuvants in polymer-based ABS, change the coexisting phases' characteristics and modify the partition behavior of biomolecules. In general, a positive effect derived from the use of ILs as adjuvants in PEG-salt systems is observed, particularly when dealing with more hydrophobic biomolecules, whereas IL + salt ABS perform better in the extraction of more hydrophilic biomolecules. The favourable partition of more hydrophilic biomolecules in IL + salt ABS seems to be ruled by specific interactions with the IL, while the favourable partition of more hydrophobic biomolecules in PEG + salt and PEG + salt + IL seems to be governed by the differences in the phases hydrophobicities. It is shown that ILs preferentially migrate to the PEG-rich phase, and that there is a correlation between the partition coefficients of the biomolecules and ILs and the biomolecules octanol-water partition coefficients.

Application of linear gradient elution in countercurrent chromatography for the separation of triterpenoid saponins from the roots of Pulsatilla koreana Nakai.

A linear gradient elution method using countercurrent chromatography was developed for the separation of four triterpenoid saponins from the roots of Pulsatilla koreana Nakai, including hederacolchiside E, which is responsible for the neuroprotective activity of this plant. The target fraction was obtained by 80% methanol elution of solid phase column chromatography. The partition coefficients of the target compounds were very different, which means they are difficult to separate with a single biphasic solvent system. Several important parameters for gradient elution, such as addition of alcohol content to the solvent system, starting point of the second mobile phase, and the time for the gradient change were logically determined and optimized. Four triterpenoid saponins could ultimately be separated, analyzed by high-performance liquid chromatography, and their structures were identified by comparing the mass spectra and NMR spectra with the literature data. The compounds and yields were: hederasaponin B (1; 21.3mg/100mg), hederacolchiside E (2; 19.8mg/100mg), cernuoside A (3; 18.4mg/100mg), and cernuoside B (4; 17.3mg/100mg). Gradient-elution countercurrent chromatography allows the effective separation of compounds with a wide polarity range.

Importance of optimizing chromatographic conditions and mass spectrometric parameters for supercritical fluid chromatography/mass spectrometry

Supercritical fluid chromatography/mass spectrometry (SFC/MS) has great potential in high-throughput and the simultaneous analysis of a wide variety of compounds, and it has been widely used in recent years. The use of MS for detection provides the advantages of high sensitivity and high selectivity. However, the sensitivity of MS detection depends on the chromatographic conditions and MS parameters. Thus, optimization of MS parameters corresponding to the SFC condition is mandatory for maximizing performance when connecting SFC to MS. The aim of this study was to reveal a way to decide the optimum composition of the mobile phase and the flow rate of the make-up solvent for MS detection in a wide range of compounds. Additionally, we also showed the basic concept for determination of the optimum values of the MS parameters focusing on the MS detection sensitivity in SFC/MS analysis. To verify the versatility of these findings, a total of 441 pesticides with a wide polarity range (logPow from −4.21 to 7.70) and pKa (acidic, neutral and basic). In this study, a new SFC-MS interface was used, which can transfer the entire volume of eluate into the MS by directly coupling the SFC with the MS. This enabled us to compare the sensitivity or optimum MS parameters for MS detection between LC/MS and SFC/MS for the same sample volume introduced into the MS. As a result, it was found that the optimum values of some MS parameters were completely different from those of LC/MS, and that SFC/MS-specific optimization of the analytical conditions is required. Lastly, we evaluated the sensitivity of SFC/MS using fully optimized analytical conditions. As a result, we confirmed that SFC/MS showed much higher sensitivity than LC/MS when the analytical conditions were fully optimized for SFC/MS; and the high sensitivity also increase the number of the compounds that can be detected with good repeatability in real sample analysis. This result indicates that SFC/MS has potential for practical use in the multiresidue analysis of a wide range of compounds that requires high sensitivity.

Optimized selection of liquid chromatography conditions for wide range analysis of natural compounds

Plant secondary metabolites are an almost unlimited reservoir of potential bioactive compounds. In view of the wide chemical space covered by natural compounds, their comprehensive analysis requires multiple and complementary approaches. In this study, numerous chromatographic conditions were tested for the analysis of a set of 120 representative natural compounds covering a wide polarity range (18 log P units). The experiments were performed on 59 different conditions involving 29 RPLC and HILIC dedicated stationary phases, as well as more exotic mixed mode columns. The best RPLC and HILIC conditions were determined using Derringer’s desirability functions, based on various criteria (i.e. retention, peak shape, distribution of compounds during the gradient…). After this first selection, only the most promising conditions were kept (19 in RPLC and 11 in HILIC). The selectivity complementarity among each chromatographic mode was assessed by principal component analysis (PCA) and hierarchical cluster analysis (HCA). In RPLC, a pentabromobenzyl (PBrBz) stationary phase was identified as particularly versatile and could constitute an elegant first intention screening column. Two additional conditions allowed to extend the range of natural compounds space that can be analyzed, while offering better selectivity for basic analytes (hybrid silica graft with C8 moiety operated at pH 9 (Hyb C8)) and acidic compounds (positively charged hybrid silica graft with pentafluorophenyl moiety (Hyb+ PFPh). Although less generic in terms of amenable compounds, an ion exchange/RP mixed mode stationary phase (MM TriP1) offered notably enhanced retention of more polar analytes under RPLC conditions. With these four conditions, 89% of the natural substances were detected by LC–MS with acceptable retentions and peak shapes. In HILIC, four acceptable and complementary conditions were also highlighted. Both Syncro-Z (zwitterionic HILIC phase) and Diol columns were found to offer balanced retention and selectivity for most of the polar compounds (log DpH3<1.0). These two columns could be advantageously complemented by hybrid Amide column operated at pH 3 and Amino stationary phase at pH 5, to further enhance both retention and selectivity of polar basic and acidic species, respectively.

Establishment of a non-invasive method for stress evaluation in farmed salmon based on direct fecal corticoid metabolites measurement

Fish welfare is an important issue for growth of the aquaculture industry. Stress responses represent animal's natural reactions to challenging conditions and could be used as a welfare indicator. Cortisol level is relevant to fish welfare condition, and is a readily measured component of the primary stress response system. Generally, cortisol is measured by blood sampling. However, fish blood cortisol level could be instantly influenced by handling-stress at sampling. Fecal corticoid metabolites (FCM) are a mixture of several different metabolites with a wide range of polarities. Thus, feces could be promising alternative less handling-sensitive and non-invasive biological matrices for cortisol evaluation in Atlantic salmon. In this study we developed non-invasive method for determination of fecal corticoid metabolites in farmed Atlantic salmon (Salmo salar L.) using enzyme-linked immunosorbent assay (ELISA).It was demonstrated that salmon FCM extracted from salmon feces is insoluble in non-polar solvents like diethyl ether, but well soluble in polar solvents like methanol. The proper extraction ratio could be one ml 100% methanol for 100 μL of the liquid part of salmon feces or 100 mg of the solid part. The FCM directly detected in unextracted liquid part of feces correlated well with the FCM extracted from both liquid and solid part of the corresponding samples, without significant difference. Thus, it is feasible to measure FCM directly in the liquid part of salmon feces without any extraction procedure.Then, we applied this assay for FCM analysis in the group of salmon that experienced salmon pancreas disease (PD) and amoebic gill disease (AGD). We demonstrated 1) both plasma cortisol and FCM increased significantly during the outbreak of inflammatory disease (P < 0.01). Plasma cortisol level was elevated from 28 ± 40 ng/ml to 164.4 ± 62.5 ng/ml, FCM from 14.4 ± 13.2 ng/ml to 170.7 ± 89.7 ng/ml 2) Growth and starvation has no significant impact on either cortisol or FCM level. 3) FCM correlated well with plasma cortisol level (P < 0.01). Furthermore, there seems more individual variation in plasma cortisol levels than in FCM levels.These results suggest FCM could be directly analyzed in liquid part of salmon feces without extraction. This directly detected FCM level could represent the total fecal FCM level and plasma cortisol level. This simple and non-invasive method makes FCM a proper indicator for salmon welfare.

Introduction of agarose gel as a green membrane in electromembrane extraction: An efficient procedure for the extraction of basic drugs with a wide range of polarities

Developing green methods for analyte extraction is one of the most important topics in the field of sample preparation. In this study, for the first time, agarose gel was used as membrane in electromembrane extraction (EME) without using any organic solvent, for the extraction of four model basic drugs (rivastigmine (RIV), verapamil (VER), amlodipine (AML), and morphine (MOR)) with a wide polarity window (log P from 0.43 to 3.7). Different variables playing vital roles in the proposed method were evaluated and optimized. As a driving force, a 25V electrical field was applied to make the analyte migrate from sample solution with pH 7.0, through the agarose gel 3% (w/v) with 5mm thickness, into an acceptor phase (AP) with pH 2.0. The best extraction efficiency was obtained with an extraction duration of 25min. With this new methodology, MOR with high polarity (log P=0.43) was efficiently extracted without using any carrier or ion pair reagents. Limits of detection (LODs) and quantification (LOQs) were in the ranges of 1.5–1.8ngmL−1 and 5.0–6.0ngmL−1, respectively. Finally, the proposed method was successfully applied to determine concentrations of the model drugs in the wastewater sample.

Solvent Effects on the Intramolecular Charge Transfer Character of N,N-Diaryl Dihydrophenazine Catalysts for Organocatalyzed Atom Transfer Radical Polymerization.

The nature of intramolecular charge transfer of N,N-diaryl dihydrophenazine photocatalysts (PCs) in different solvents is explored in context of their performance in organocatalyzed atom transfer radical polymerization (O-ATRP). PCs having a computationally predicted lowest energy excited state exhibiting charge transfer (CT) character can operate a highly controlled O-ATRP in a wide range of solvent polarities, from non-polar hexanes to highly polar N,N-dimethylacetamide. For PCs having a computationally predicted lowest energy excited state not possessing CT character, their ability to operate a controlled O-ATRP is decreased. This study confirms the importance of CT character in the excited state for N,N-diaryl dihydrophenazine PCs, and a deeper understanding of the activity of CT PCs has enabled the synthesis of polymers of low dispersity ( < 1.10) in a controlled fashion.

Phenolic composition of pomegranate peel extracts using an liquid chromatography-mass spectrometry approach with silica hydride columns.

The peels of different pomegranate cultivars (Molla Nepes, Parfianka, Purple Heart, Wonderful and Vkunsyi) were compared in terms of phenolic composition and total phenolics. Analyses were performed on two silica hydride based stationary phases: phenyl and undecanoic acid columns. Quantitation was accomplished by developing a liquid chromatography with mass spectrometry approach for separating different phenolic analytes, initially in the form of reference standards and then with pomegranate extracts. The high-performance liquid chromatography columns used in the separations had the ability to retain a wide polarity range of phenolic analytes, as well as offering beneficial secondary selectivity mechanisms for resolving the isobaric compounds, catechin and epicatechin. The Vkunsyi peel extract had the highest concentration of phenolics (as determined by liquid chromatography with mass spectrometry) and was the only cultivar to contain the important compound punicalagin. The liquid chromatography with mass spectrometry data were compared to the standard total phenolics content as determined by using the Folin-Ciocalteu assay.