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Well-established label in biomolecules analysis, fluorescein isothiocyanate is commercially available in its two different isomers with equal fluorescence sensitivity, differing in meta- vs. para-isothiocyanate position. It was found in this study that the stability of the isomers depends on the polarity of different solvents and the pyridine (stabiliser) presence. The lowest stability has fluorescein isothiocyanate in water solvent. In acidic solution, their quinoid (acid) form switches to the lactone form. The p-quinoid form has higher tendency to create dimers and trimers and is less soluble in acetone than the lactone form. [GRAPHICS] .

The research was done with partial filling micellar electrokinetic chromatography, microemulsion electrokinetic chromatography, and ultra-high performance liquid chromatography. The study focuses on determination of male and female steroids from cold and hot tap water of households in Helsinki City. The district ' s raw water is made run from Paijanne Lake through a water tunnel to the purification plants in Helsinki area. The effluents delivered from the plants to households as tap water were sampled and used for the study. They were concentrated with solid phase extraction to exceed the detection limits of the three methods. With partial filling method the limits were 0.50, 0.48, 0.33, and 0.50 mg/L for androsterone, testosterone, progesterone, and testosterone-glucuronide, respectively. In microemulsion method the limit values were 1.33, 1.11, and 0.40 mg/L for androsterone, testosterone, and progesterone, respectively, and 0.83, 0.45, and 0.50 mg/L for hydrocortisone, 17-alpha-hydroxyprogesterone, and 17-alpha-methyltestosterone, respectively. In the tap water samples, progesterone concentrations represented the highest values being 0.22 and 1.18 ng/L in cold and hot water, respectively. They also contained testosterone (in all samples), its glucuronide metabolite (in 25% of the samples), and androstenedione (in 75% of the samples). The ultra-high liquid chromatographic method with mass spectrometric detection was used for identification of the steroids at mu g/L level. (c) 2021 Elsevier B.V. All rights reserved.

A novel analytical-scale concept to improve reliability of detection and analysis of natural and processed wastewater samples from a purification plant was developed. A sequential sample clean-up system of polymer-based octadecyl and silane-based quaternary amine sorbents were used for concentrating human based steroid hormones and their metabolites and detecting them by UV absorption with capillary electrophoresis (CE). The water samples were collected from influent and effluent processes of the water purification plant in Helsinki, Finland. The CE methods were partial-filling micellar electrokinetic chromatography and capillary zone electrophoresis. The analysis times and method concentration levels were optimized with eight steroids at the range of 0.5–10 mg/L. Since in CE the detectable quantities were higher than the existing amounts in the process waters, the real samples needed matrix removal combined with steroid enrichment. After 20,000-fold concentration testosterone-glucoside, androstenedione, progesterone, and estradiol-glucoside could be determined in the process water samples. The amounts of individual steroids in influent and effluent waters were 0–429 and 0–207 ng/L, respectively. Correspondently, their total amounts were 735 and 212 ng/L with excellent in day and inter-day repeatability. The RSD values were less than 1, 9.7, and 19% in repeated analyses, calculated from 60 analyses during 24 h, and from 130 analyses during 15 months, respectively. The steroid removal in purification process was 65% on average. The solid particles separated in three steps during the water clean-up concept contained 9.8–45 ng/g steroids in combined dry precipitates.

Immunoaffinity procedure was developed for isolation of low density lipoprotein (LDL) from biological samples by using silica-derived immunoaffinity sorbent. Sorbent was prepared by immobilization of monoclonal anti-apoB-100 antibody onto macroporous silica particles, using carefully optimized binding chemistry. Binding capacity of the sorbent towards LDL was determined by batch extraction experiments with solutions of isolated LDL in phosphate-buffered saline, and found to be 8 mg LDL/g. The bound LDL fraction was readily released from the sorbent by elution with ammonia at pH 11.2. The total time needed for isolation procedure was less than 1 h, with LDL recoveries being essentially quantitative for samples containing less than 0.3 mg LDL/mL. With higher concentrations, recoveries were less favorable, most probably due to irreversible adsorption caused by LDL aggreggation. However, reusability studies with isolated LDL at concentration 0.2 mg/mL indicate that the developed immunoaffinity material may be used for multiple binding-release cycles, with minor losses in binding capacity. Finally, the sorbent was successfully applied to isolation of LDL from diluted plasma. Apart from its practical implications for LDL isolation, this study provides crucial insights into issues associated with LDL-sorbent interactions, and may be useful in future efforts directed to development of lipoprotein isolation approaches.

The present article examines recently published literature on lipids, mainly focusing on research involving glycero-, glycerophospho- and sphingo-lipids. The primary aim is identification of distinct profiles in biologic lipidomic systems by ultra-high-performance liquid chromatography (UHPLC) coupled with mass spectrometry (MS, tandem MS) with multivariate data analysis. This review specifically targets lipid biomarkers and disease pathway mechanisms in humans and artificial targets. Different specimen matrices such as primary blood derivatives (plasma, serum, erythrocytes, and blood platelets), faecal matter, urine, as well as biologic tissues (liver, lung and kidney) are highlighted.

The azoles (represented by penconazole, cyproconazole, and tebuconazole in this study) are frequently used agrochemicals to protect various crops against mildew and fungi. They are considered as endocrine disruptors, because they block the biosynthesis (on the level of enzymes inhibition) of biochemicals with steroid structure. Besides targeted impacts, they can partly get into the soil with the rainfall or litter fall and influence/block the biosynthesis of sterols of non-target organisms. In this sense, the risk of disruption of rhizosphere plant-microbial symbiosis and dynamic processes in the soil solution by azoles is of high importance to be evaluated. We have developed an analytical methodology for determination of penconazole, cyproconazole, and tebuconazole in soil solution using capillary electrophoresis with a photodiode array detector at UV-214 nm and acidic electrolyte solution (pH 1.48). The results were also compared with mass spectrometric measurements using mu-TOF mass spectrometry. There approx. 90% of present azoles were bound in the soil solution matrix. The detection limit for these azoles is about 10(-7) mol dm(-3). Because of very low pK(a) of azoles, we have to consider deprotonation of azoles and consequently the high affinity to create complexes with cations. The majority of present azoles in soil solution might form neutral adducts with mono-cations, making them invisible in electrospray mass spectra. [GRAPHICS] .

Microemulsion gels were synthetized from macadamia, linseed, olive, walnut, rapeseed, sesame, and coconut oils and frying oil made from sunflower, palm, and rapeseed oils. The gels were similar as polyacrylamide-based gels with exception of replacing dodecyl sulfate with vegetable oils. The gels were modified with celluloses, cotton, or lignin to make the emulsions sustainable for water purification. They were used to compare sorption properties when they were used as solid-phase adsorbents in isolation of steroids from water. Hydrophobicity features of the gels were compared by detecting adsorption and extraction efficiency of nonpolar androstenedione, testosterone, and progesterone, which exist in wastewater and drinking water. Quantification was done with partial filling-micellar electrokinetic chromatography with 29.5 mM sodium dodecyl sulfate-3.4 mM sodium taurocholate as the micelle and 20 mM ammonium acetate (pH 9.68) as the electrolyte. UV-detection was used. Methanol was the best eluent for extraction of steroids from gels. The highest recoveries were from frying oil and rapeseed oil gels modified with celluloses. They also possessed the best floating properties on water surface. Lignin modified gels were too hydrophilic, when in touch with water they filled up with water. They also had the lowest capacity.

Partial-filling micellar electrokinetic capillary chromatography (PF-MEKC) with UV detection was applied for determination of human-based steroids in water samples of Finnish wastewater treatment plants. The samples were purified with solid-phase extraction (SPE) on octadecyl substituted polymer sorbents obtaining analyte enrichment of 20,000-fold. The steroids studied were androgens, estrogens, and progesterone. Three of the steroids could be quantified with the PF-MEKC method. The detection and quantification limits were 0.05–1.06 μg/mL and 0.15–3.2 μg/mL, meaning in the SPE concentrates as 2.5–53 pg/L and 7.5–160 pg/L, respectively. In the influent waters, the total amount of testosterone glucuronide, androstenedione, and progesterone was up to 350 ng/L. In effluent water samples the total steroid quantity was maximum at 320 ng/L. Remarkably high quantity of androstenedione was quantified in both influent and effluent water samples. The cleanest effluent waters were produced in Western Finland....

A method based on direct UV-detection was developed for the qualitative and quantitative determination of oligosaccharides simultaneously separated by capillary electrophoresis (CE). Reference compounds consisting of five xylo- three manno- and five cello-oligosaccharides were concurrently measured in a highly alkaline solution without derivatization. Sodium and potassium cations were used in the electrolyte solution to adjust the electrokinetic properties of the oligomers by controlling the mobility of charged species and to improve the resolution in baseline separation. The quantification range extended from 25 to 125 mg/L with linear correlation $$\hbox {R}^{2}=0.986{-}0.997$$ for all analytes other than xylobiose and cellobiose, for which the range was 50–200 mg/L ( $$\hbox {R}^{2}=0.995$$ ). The CE method developed was further applied to determine oligosaccharides from hot-water extracts of a bleached birch and pine kraft pulp, in which the oligosaccharides typically exist as complex mixtures.

Tuberculosis is a devastating contagious disease caused by Mycobacterium tuberculosis. This is the first report describing the development of novel capillary electrophoresis methods to detect lipoarabinomannans shed into the blood circulation by replicating bacteria. The novelty of the methods is the detection without derivatization. The lipoarabinomannan is detected owing to the ionization of the diverse functional groups of the structure, such as the multibranched mannan domain or the phosphatidyl group. Four alkaline solutions were used; normal polarity in three of them and reversed polarity in one. Urinary lipoarabinomannans by saccharide domains were identified with direct absorbance detection. The accuracy and the analytical sensitivity were then validated with cello-, manno- and xylooligosaccharides. Lipoarabinomannan detection was feasible within 20 min (RSD 2.1%). This method worked at the dynamic range of 0.1-10 μg/mL. With reversed polarity, indirect absorbance detection, and pH 9.0 electrolyte were used, the analytes migrated already within 5 min (RSD 0.01%). Inorganic nonabsorbing ions were used for this method optimization. This improvement resulted in the detection limit of 1 pg/mL in water and in the linear dynamic range of 1 pg/mL to 10 ng/mL. In conclusion, the described method has great potential as a point-of-care assay for clinical use.

Organic acids are used for starting compounds in material sciences and in biorefinery, food, fuel, pharmaceutical, and medical industry. Here, we provide the data from a biochemical approach made to investigate production of organic acids and isolation of metals from wood, which is the most abundant biomass. Spruce and bark, phloem, and heartwood from pine were fermented with either microbes of oyster mushroom (Pleurotus ostreatus), baker's yeast, or lactic acid bacteria to improve selective fermentation. Using capillary electrophoresis and liquid chromatography techniques, we identified 14 different organic acids and phenolic acids with good yields. With inductively coupled plasma atomic emission spectroscopy 11 metals were quantified and further detailed analysis/results from these data are available in Sirén et al. (2015).

The review concentrates on the properties of analytical and statistical ultrahigh-performance liquid chromatographic (UHPLC) – mass spectrometric (MS) methods suitable for glycero-, glycerophospho- and sphingolipids in lipidomics published between the years 2017–2019. Trends and fluctuations of conventional and nano-UHPLC methods with MS and tandem MS detection were observed in context of analysis conditions and tools used for data-analysis. Whereas general workflow characteristics are agreed upon, more details related to the chromatographic methodology (i.e. stationary and mobile phase conditions) need evidently agreements. Lipid quantitation relies upon isotope-labelled standards in targeted analyses and fully standardless algorithm-based untargeted analyses. Furthermore, a wide spectrum of setups have shown potential for the elucidation of complex and large datasets by minimizing the risks of systematic misinterpretation like false positives. This kind of evaluation was shown to have increased importance and usage for cross-validation and data-analysis.

This is an Open Access Article. It is published by International Union of Pure and Applied Chemistry (IUPAC) under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Licence (CC BY-NC-ND). Full details of this licence are available at: http://creativecommons.org/licenses/by-nc-nd/4.0/

Xanthates enhance the separation of valuable metals from minerals in hydrometallurgical processes. They degrade to structurally related decomposition products under the chemical and physical conditions in flotation processes, which minimizes the extraction recovery of metals. To monitor low quantities of the decomposition products, the flotation process requires sensitive, qualitative, or even quantitative controlling. The goal of the present research was to develop a sensitive separation method for on-line monitoring of the degradation of collector chemicals in the waters of a gold concentrator plant. To that end, an on-line coupling of capillary electrophoresis with a pressure-assisted field-amplified sample injection (PA-FASI) was developed. The purpose of the overall system set-up was to fortify concentrations during sample introduction in order to study xanthates and thiocarbonate directly in flotation waters during the process. The system developed from these methods was reliable and reproducible, enabling detection of below 10 mg L −1 quantities for ethyl and isobutyl xanthates as well as for isobutyl thiocarbonate.

Bioprocessing of pine bark was accomplished using oyster mushroom fungi. The organic acids and inorganic anions in the extracts of fermented samples were identified by capillary electrophoresis (CE). Nine organic acids were simultaneously determined in 12 min through the use of an electrolyte composed of 20 mM pyrazine-2,3-dicarboxylic acid (2,3-PyDC), 1.5 mM CaCl 2 ·2H 2 O and 0.3 mM MTAH in methanol:water (10:90, v/v) at pH 9.0. The concurrent determinations of three inorganic anions were performed in less than 10 min in an electrolyte consisting of 2.25 mM pyromellitic acid, 6.50 mM NaOH, 0.75 mM hexamethonium hydroxide, and 1.60 mM triethanolamine at pH 7.70. The applied analysis methods efficiently separated and identified organic acids and inorganic anions in the extracts. Butyric, maleic and glucuronic acids were the primary organic acids formed via fermentation. Chloride, nitrate and sulphate were detected in all of the samples.

The amino acid composition of cultivation broth is known to affect the biomass accumulation, productivity, and vitality of yeast during cultivation. A separation method based on capillary electrophoresis with laser-induced fluorescence (LIF) detection was developed for the determination of amino acid consumption by Saccharomyces cerevisiae during beer fermentation. Intraday relative standard deviations were less than 2.1% for migration times and between 2.9% and 9.9% for peak areas. Interday relative standard deviations were less than 2.5% for migration times and between 4.4% and 18.9% for peak areas. The quantification limit was even as low as 62.5 pM which equals to below attomole level detection. The method was applied to study the rate of amino acid utilization during beer fermentation.

Steroid hormones, botrydial, and inorganic ions were studied from cold and hot tap water samples with capillary electrophoresis techniques using UV detection. Identification of the steroids and botrydial was made with ultra-high -performance liquid chromatography (UHPLC) coupled to electrospray ionization orbitrap high-resolution mass spectrometry. Solid phase extraction with nonpolar and ion-exchange sorbents was needed to enrich the compounds for CE and UHPLC studies. The steroids identified from the drinking water samples were estradiol glucoside, androstenedione, testosterone, and progesterone. However, only progesterone could be quantified in both cold and hot tap water samples from Helsinki households. Its concentration varied from 0.031 ng/L to 0.135 ng/L and from 0.054 ng/L to 0.191 ng/L, respectively. Chloride and nitrate amounts were 25 mg/L. Calcium, potassium, magnesium, and sodium were 20, 1, 1, and 17 mg/L at the highest, respectively. Copper, iron, sulphate, and ammonium were below the methods concentration limits. Botrydial from Botrytis cinerea mould was identified in all drinking waters. In both cold and hot tap waters its concentration was 861-3900% higher than in a drilled well water that was also used as the household tap water. The mould was also confirmed by identification of its metabolite abscisic acid. (C) 2017 Elsevier B.V. All rights reserved.

Ion-imprinted polymers (IIPs) for nickel were synthesized by inverse suspension copoly-merization of vinylbenzyl iminodiacetic acid (VbIDA) with ethyleneglycol dimethacrylate (EDMA) in the presence of nickel(II) ions with various porogen solvents to study their impact on the IIPs properties. They were prepared with mixtures of acetonitrile and dimethylsulfoxide (DMSO), 50/50%v/v, for IIP-A/D and 2-methoxyethanol and DMSO, 50/50%v/v, for IIP-M/D. The structure and properties of these polymers were compared with those of IIP-D previously prepared with pure DMSO as porogen solvent. Although IIP-A/D and IIP-M/D were less porous than IIP-D, they presented better nickel adsorption properties and selectivity towards Zn2+, Co2+ and Pb2+. This is assumed to be the result of the stabilization of the ligand-metal complex during the polymerization process. Moreover, the nickel binding capacities of the prepared IIPs in competitive conditions are remarkably high (184 mu mol/g for IIP-D, 170 mu mol/g for IIP-A/D and 174 mu mol/g for IIP-M/D). The impact of the VbIDA chelating monomer was highlighted by comparing the adsorption properties of a copolymer of methyl methacrylate (MMA) and EDMA with NIP-D. It was proved that the methacrylic polymer matrix has low binding properties. (C) 2016 Elsevier Ltd. All rights reserved.

The aim of this research was to extend an existing capillary electrophoresis (CE) method, originally developed for the determination of mono- and disaccharides, to the determination of alternative carbohydrate compounds, namely furfural and polydatin. Empirical validation confirms that this novel method can be applied for the determination of analyte concentrations from complex matrices, and the evaluation of their carbohydrate composition. It is concluded that the approach has validity as an analytical procedure and has the ability to determine industrially important analytes from a heterogeneous biological sample matrix, and thus, the method adds value to the development of large scale separation processes. However, some additional optimization is required before online applications.

Statins were separated and quantified with gas chromatography-mass spectrometry (GC-EI-MS/MS) using total ion monitoring (TIC) and multiple reactions monitoring (MRM). The MRM method in statins determination has a novelty value, since there are no previous studies on their simultaneous analysis in environmental or plant samples. The method development and optimization was challenging due to the physicochemical similarities of the silylated lovastatin, simvastatin, pravastatin, fluvastatin, and atorvastatin. The results showed that the use of MRM decreased their detection and quantification limits by factors of 2-10 compared to that obtained in TIC monitoring. The concentration calibration was made between 247.5ng/L and 9900ng/L. Limits of detection and quantification were between 50ng/L (lovastatin)-500ng/L (pravastatin) and 250ng/L (lovastatin)-1000ng/L (pravastatin), respectively. Based on the MRM results, the wood bark and phloem samples contained lovastatin, lovastatin-lactone, simvastatin, simvastatin-lactone, and pravastatin. Their concentrations were 250-3000μg/L, i.e. 4.2-50mg/kg in phloem and bark. However, they were not detected in fluids made with Pleurotus ostreatus fermentation of wood core.

The effect of ethanol concentration on the removal of bisphenol A (BPA) from water-ethanol mixtures using pulverized activated carbon (PAC) was studied. Adsorption equilibria and kinetics were measured using batch uptake experiments. Equilibrium and kinetic data were correlated with the Langmuir model and the non-ideal competitive adsorption (NICA) model. Finally, BPA removal in an adsorption-microfiltration hybrid system was tested and simulated with a non-steady model. Ethanol has a strong influence on the binding capacity of BPA on PAC and the uptake from 10 mol/L (50.4 wt-%) aqueous ethanol is less than 10% of the value measured in water. The experimental adsorption isotherms were modeled using several isotherm models and by considering the effect of ethanol on solution activity coefficients. The best correlation was obtained with the NICA model assuming that part of the binding sites is inaccessible for BPA. The BPA adsorption rate was described using a pore diffusion model and reasonably good correl...

The steroids, hydrocortisone, androstenedione, 17-α-hydroxyprogesterone, testosterone, 17-α-methyltestosterone, and progesterone were separated with microemulsion electrokinetic chromatography (MEEKC) and detected with UV absorption. The microemulsion phases were prepared from both artificial and vegetable oils, from them the first was made of alkane and alcohol and the latter from colza, olive, linseed, and walnut oils. The electrolyte solutions were made to emulsions using sodium dodecyl sulfate and alkaline tetraborate. The solution mixtures made from ethyl acetate, sodium dodecyl sulfate, 1-butanol, acetonitrile, and sodium tetraborate were used as the reference solutions to evaluate the performance of the vegetable oil emulsions. Our study showed that the lipophilic organic phase in the microemulsion did provide resolution improvements but not selectivity changes. The results also correlate with real interactions of the steroids with the lipophilic organic microemulsion phase. The quality of the oils between the manufacturers did not have importance, which was noticed from the equal behavior of the steroids in the vegetable oil emulsions. Detection limits of the steroids in vegetable oil emulsions were at the level of 0.20–0.43 μg/L. Thus, they were 2–10 times higher than the concentrations in the partial filling micellar electrokinetic chromatography (PF-MEKC), which we have obtained earlier. The repeatability (RSD%) of the electrophoretic mobilities of the steroids was between 0.50 and 3.70. The RSD% values between the inter-day separations were below 1%, but when walnut and olive oils were used the values exceeded even 10%.

The effect of acrylonitrile co-polymerization and molecular imprinting on bisphenol A (BPA) affinity by the polystyrene-divinylbenzene adsorbents was studied. Adsorption equilibria were measured using batch uptake experiments and equilibrium data were analyzed by means of Langmuir isotherm and Scatchard approach. The calculated parameters were utilized for modeling of adsorption–microfiltration hybrid system. The highest BPA capacity, 27 mg/g, is achieved for the material synthesized with 10% BPA template concentration in relation to monomer. Acrylonitrile does not improve BPA affinity or adsorption capacities of sorbents. BPA sorption rate can be described assuming pore diffusion control and using a tortuosity factor of 3. The estimated equilibrium and mass transport parameters describe reasonably well the removal of BPA in the adsorption–microfiltration hybrid system. Model calculations show that 97% reduction in BPA concentration is attained with sufficiently high amount of the adsorbent.

Three different commercial β-1,4-endoxylanase preparations were used to hydrolyze bleached kraft pulp. Xylo-oligosaccharides in the produced filtrates were separated and quantified using both high performance liquid chromatography (HPLC) and capillary electrophoresis (CE). All the determinations were performed without sample derivatization. The analytical methods were used to highlight the differences between the enzymes behaviour in terms of hydrolysates, but also to estimate the productivity of xylo-oligosaccharides from kraft pulp when the bleached material would be used in biorefining industry. The research showed that the glycosyl hydrolase family 10 enzyme produced by Aspergillus oryzae released xylobiose and xylotriose from the pulp material. The major oligosaccharides released by the family 11 enzyme produced by Bacillus sp. were xylotriose, xylobiose and xylotetraose. On the contrary, another family 11 enzyme produced by A. oryzae produced also xylose. The HPLC results agreed well with the xylose concentrations obtained after acid hydrolysis. The CE data showed the same trend, but much lower concentrations were identified than with HPLC. At the same time the HPLC method was able to separate only small oligosaccharides, whereas CE could be used for separation of all the xylo-oligosaccharides from xylobiose to xylohexaose. The highest xylo-oligosaccharide yield was achieved with Shearzyme at pH 5 corresponding to 22 % of total xylan from bleached birch kraft pulp.

Hydrolysates of lignocellulosic biomass, used as substrates for the sustainable production of fuels and chemicals often contain high amounts of phenolic compounds inhibiting the production microbiota. Quantification of these inhibitor compounds may help to understand possible difficulties in bioprocessing and further the development of more efficient, robust and tolerable processes. A separation method based on capillary electrophoresis with UV detection was developed for the simultaneous quantification of 10 phenolic compounds that may have inhibitor properties. Intraday relative standard deviations were less than 0.7% for migration times and between 2.6% and 6.4% for peak areas. Interday relative standard deviations were less than 3.0% for migration times and between 5.0% and 7.2% for peak areas. The method was applied to demonstrate that Saccharomyces cerevisiae was able to decrease the concentrations of vanillin, coniferyl aldehyde, syringaldehyde, acetoguaiacone and cinnamic acid during the cultivation, whereas the concentrations of phenols increased.

Two complementary instrumental techniques were used, and the data generated was processed with advanced numerical tools to investigate the interactions between anti-human apoB-100 monoclonal antibody (anti-apoB-100 Mab) and apoB-100 containing lipoproteins. Partial Filling Affinity Capillary Electrophoresis (PF-ACE) combined with Adsorption Energy Distribution (AED) calculations provided information on the heterogeneity of the interactions without any a priori model assumptions. The AED calculations evidenced a homogenous binding site distribution for the interactions. Quartz Crystal Microbalance (QCM) studies were used to evaluate thermodynamics and kinetics of the Low-Density Lipoprotein (LDL) and anti-apoB-100 Mab interactions. High affinity and selectivity were observed, and the emerging data sets were analysed with so called Interaction Maps. In thermodynamic studies, the interaction between LDL and anti-apoB-100 Mab was found to be predominantly enthalpy driven. Both techniques were also used to study antibody interactions with Intermediate-Density (IDL) and Very Low Density (VLDL) Lipoproteins. By screening affinity constants for IDL-VLDL sample in a single injection we were able to distinguish affinity constants for both subpopulations using the numerical Interaction Map tool. (C) 2016 Elsevier Inc. All rights reserved.

Capillary electrophoresis was used for determination of inorganic alkali and alkali earth metal cations, inorganic anions, anions of organic acids, and carbohydrates in six Pinot Noir grape red wines. Spectrum analysis was applied to evaluate the possible chemical differences between the wines from different geographic origin. In addition, sensory evaluation was used to reveal differences between wines from the end user point of view. Both chemical analyses and the sensory evaluation revealed clear differences among the wine samples. The total concentrations of inorganic ions, carboxylate anions, and carbohydrates varied 1.9–3.1 g L−1, 4.3–5.5 g L−1, and 1.5–7.5 g L−1, respectively. Although the grape was same in all samples, the results show considerable variations in chemical composition, the red wine from Tasmanian being the most different among samples.

Capillary zone electrophoresis (CZE) with indirect UV detection was used in developing a method for the simultaneous determination of inorganic anions, aliphatic and heterocyclic organic acids in various processed samples. The analytes were determined simultaneously in 10 min using an electrolyte containing 20 mM 2,3-pyrazine dicarboxylic acid, 65 mM tricine, 2 mM BaCl2, 0.5 mM cetyltrimethylammonium bromide, and 2 M urea at pH 8.06. Linear plots for the analytes were obtained in the concentration range of 2–150 mg L−1. Relative standard deviations (RSDs) of peak areas during a 3-day analysis period varied from 5.5% for glycolate to 9.5% for oxalate. RSDs of migration times varied between 0.4% and 1.1%. The detection limit (at S/N 3) was 1 mg L−1 for all the analytes studied. The proposed method was successfully demonstrated for the determination of carboxylic acids in eight oxygen treated samples of commercial softwood and hardwood kraft lignin and two red wine samples of Pinot Noir grapes. In the kraft lignin samples the concentrations of carboxylic acids correspond to the oxidation time. The acid concentrations of wine varied considerable.

Silicon–glass microchips were designed and fabricated for on-chip solid phase extraction (SPE) and zone electrophoresis studies. The solvent channels for extraction and the separation channels for analyses were fabricated sequentially on the silicon device. Electrical contacts were integrated in a fused silica glass lid. Amorphous silicon thin film electrodes were fabricated for high voltage and conductivity detection. A chip installation rack with electrical and fluidic contacts was constructed to facilitate the experiments. Simulation was used to elucidate both the liquid flow and the electric field distribution. The operational performance of the microchips was demonstrated by using a fluorescein isothiocyanate (FITC)-labelled testosterone derivative as the model analyte and fluorescein as both the negative control and the calibration compounds. In SPE an immunosorbent, based on recombinant anti-testosterone Fab-fragments, was immobilized to activated Sepharose gel. Simultaneous monitoring of the movement of FITC-testosterone from SPE cavity through the channel to the detection point was performed with a laser-induced fluorescence detector. The observed limit of detection for FITC-testosterone was 2 μM.

A new system for on-line analyses of metal cations has been developed by combining flow injection sample introduction with on-line capillary electrophoresis. The on-line analysis instrument has a simple construction and it allows fast sample introduction from a flowing solution. The ends of the separation capillary and the electrodes were placed opposite to each other into tubings that were installed over them behaving as flow-through channels. The capillary temperature during the analyses was controlled by water cooling and the analyte monitoring was conducted with a contactless conductivity detector. The construction allowed compound detection of very low concentrations.The instrument was used for simultaneous determination of ammonium, potassium, calcium, magnesium, and sodium as complexes in aqueous 18-crown-6 ether – acetate electrolyte solution. Flow injection analysis of sample introduction was kept apart from the ligand modified electrolyte solution. Calibration with standard mixtures of alkali metals, alkaline earth metals, and ammonium was linear in the range from 10 ng/mL to 1 µg/mL for each analyte. The intraday reproducibility for the separations was 2% (RSD). The detection limit for the cations was 10 ng/mL. The studies showed the performance of the method to be sensitive for the monitoring of inorganic ions in water treatment.

Actual mobilities and dissociation constants of six diuretics (benzthiazide, bumetanide, ethacrynic acid, furosemide, hydrochlorothiazide and chlorothiazide) and probenecid were investigated in methanol by capillary zone electrophoresis (CZE). The actual mobilities were derived from the dependence of the effective mobilities of the analytes on the pH(*) of the methanolic background electrolyte (BGE) solution. The measurement of effective mobilities was carried out mainly by a pressure-mediated capillary electrophoresis (CE) method. For comparison, parallel measurements were carried for two of the analytes by the conventional capillary electrophoresis approach, without pressure. The pK(a)(*) values in methanol were calculated by non-linear curve fitting to the measured mobility values. The difference between the pK(a) values in water and methanol was about 5 units for the loop diuretics (furosemide, bumetanide, ethacrynic acid) and probenecid and around 3-4 units for the thiazide diuretics. Knowledge of the ionisation behaviour of compounds in methanol paves the way for the wider use of methanol as background electrolyte solvent in capillary electrophoresis. Moreover, as is demonstrated in the current study, the calculation of actual mobilities and pK(a) values facilitates the optimisation of pH conditions for the separation, thereby applications can be expanded, and the combination of capillary electrophoresis with electrospray ionisation mass spectrometry becomes easier.

The aim of this study was to develop a method for comprehensive profiling of metabolites involved in mammalian steroid metabolism. The study was performed using the partial filling micellar electrokinetic chromatography (PF-MEKC) technique for determination of endogenous low-hydrophilic steroids. The detection techniques in capillary electrophoresis were UV absorption and electrospray mass spectrometry (ESI-MS). Thirteen steroids were included in the method development, and the selected were metabolites involved in major pathways of steroid biosynthesis. Although only eight of them could be separated and detected with UV, they could be identified by ESI-MS using selected ion monitoring (SIM) technique. Tandem MS spectra were also collected. UV detection was more sensitive than MS due to better separation of compounds and the selective signal sensitivity. The lowest limits of detection were 10–100 ng/mL for cortisone, corticosterone, hydrocortisone and testosterone. The other steroids could be detected at 500–1000 ng/mL. The identification of cortisone, corticosterone, hydrocortisone, estrogen and testosterone were made in patient urine samples and their concentrations were 1–40 μg/L.

The neutral sugar composition of acid hydrolyzed extracts of cellulose fiber samples, i.e. oat spelt, wheat straw, thermomechanica pulp (TMP) made of spruce, aspen stemwood, and bleached birch kraft pulp, was determined by a new capillary zone electrophoresis (CZE) method employing an alkaline background electrolyte. The method relies on in-capillary reaction and direct UV detection at wavelength 270 nm. Neutral carbohydrates d -(+)-galactose, d -(+)-glucose, l -rhamnose, d -(+)-mannose, d -(−)-arabinose, and d -(+)-xylose were simultaneously separated. The calibration plots were linear over a range from 10 to 150 mg/L for d -(+)-galactose, l -rhamnose, d -(+)-mannose, and d -(−)-arabinose and from 50 to 400 mg/L for d -(+)-glucose and d -(+)-xylose. Relative standard deviations (RSDs) of peak areas during a 5-day analysis period varied from 3.3% for galactose to 11.8% for rhamnose. RSDs of migration times varied between 0.3 and 0.7%. The detection limit (at S/N 3) was 5 mg/L for each monosaccharide. The results obtained by CZE agreed well with results obtained by high-performance anion-exchange chromatography. Glucose and xylose were the two predominant monosaccharides in the plants, except in the spruce TMP sample where glucose and mannose dominated.

ACE is a popular technique for evaluating association constants between drugs and proteins. However, ACE has not previously been applied to study the association between electrically neutral biomolecules and plasma proteins. We studied the affinity between human and bovine serum albumins (HSA and BSA, respectively) and three neutral endogenous steroid hormones (testosterone, epitestosterone and androstenedione) and two synthetic analogues (methyltestosterone and fluoxymesterone) by applying the partial-filling technique in ACE (PF-ACE). From the endocrinological point of view, the distribution of endogenous steroids among plasma components is of great interest. Strong interactions with albumins suppress the biological activity of steroids. Notable differences in the association constants were observed. In the case of the endogenous steroids, the interactions between testosterone and the albumins were strongest, and those between androstenedione and the albumins were substantially weaker. The association constants, K(b), for testosterone, epitestosterone and androstenedione and HSA at 37 degrees C were 32 100 +/- 3600, 21 600 +/- 1500 and 13 300 +/- 1300 M(-1), respectively, while the corresponding values for the steroids and BSA were 18 800 +/- 1500, 14 000 +/- 400 and 7800 +/- 900 M(-1). Methyltestosterone was bound even more strongly than testosterone, while fluoxymesterone was only weakly bound by the albumins. Finally, the steroids were separated by PF-ACE with HSA and BSA used as resolving components.

Conventional methods for the determination of testosterone in body fluids typically suffer from poor recovery, lack of specificity, complex sample pretreatment, or the need for derivatization. Here, a simple, specific, and fast analysis method for testosterone was developed, with a methodology based on testosterone-specific immunoaffinity solid-phase extraction (IA-SPE) and subsequent analysis by partial filling micellar electrokinetic chromatography (PF-MEKC). An immunosorbent consisting of a recombinant anti-testosterone Fab fragment covalently attached to activated Sepharose was prepared. IA-SPE and PF-MEKC were set up in hyphenated and off-line constructions, and the applicability of the two constructions in analysis of testosterone in male urine was investigated. The results obtained with the hyphenated construction proved to be only indicative of the presence of testosterone. The off-line IA-SPE and PF-MEKC construction, however, was successfully used in the determination of free testosterone in male urine samples after enzymatic hydrolysis of the glucuronide conjugates. Except for the hydrolysis reaction, no sample pretreatment was required. After hydrolysis, the overall analysis time per sample was only 14 min. The off-line IA-SPE PF-MEKC method proved to be robust, sensitive (limit of quantification 35 ?g/L), and specific, enabling separation of testosterone from four related steroids. Thus, it provides attractive features when compared to traditional methods for determination of testosterone in male urine.

A new CZE method relying on in-capillary reaction and direct UV detection at the wavelength 270 nm is presented for the simultaneous separation of the neutral carbohydrates xylitol, D-(-)-mannitol, sucrose, D-(+)-fucose, D-(+)-cellobiose, D-(+)-galactose, D-(+)-glucose, L-rhamnose, D-(+)-mannose, D-(-)-arabinose, D-(+)-xylose, and D-(-)-ribose. The alkaline electrolyte solution was prepared of 130 mM sodium hydroxide and 36 mM disodium hydrogen phosphate dihydrate. Separation of the sample mixture was achieved within 35 min. Calibration plots were linear in the range of 0.05-3 mM. Reproducibility of migration times was between 0.3 and 1.1%, and the detection limits for the analytes were 0.02 and 0.05 mM. The optimized method was applied for the determination of neutral monosaccharides in lemon, pineapple, and orange juices and a cognac sample. The methodology is fast since no other sample preparation except dilution is required.

International audience; In order to highlight the importance of the complex stoichiometry during ion imprinted polymer (IIP) synthesis, we investigated the effect of the complex structure on IIPs selectivity by adjusting the complex stoichiometry before polymerization. 2-(aminomethyl)pyridine monomer (amp) was chosen as a functionalized ligand for nickel(II) ions and a polymerizable vinylbenzyl derivative (Vbamp) was prepared. Complex formation was studied by varying the nickel/Vbamp ratio and recording absorption spectra of the complexes at the polymerization conditions. Using a least-squares minimization scheme, the complex species distribution was successfully established. From these results, it was possible to choose the metal/ligand stoichiometry in the complex (1:1; 1:2 or 1:3) by adjusting the initial metal/ligand ratio. IIPs were then prepared by inverse suspension copolymerization of Vbamp with ethyleneglycol dimethacrylate (EDMA). Highly porous particles with good nickel binding capacity and good Ni/Zn selectivity even at acidic conditions were obtained. Equilibrium uptake of Ni(II) at pH 7 ranged from 0.12 to 0.2 mmol g−1 and relative selective coefficient was as high as 260 for the IIP prepared using the Ni(Vbamp)2 complex.

Pinot Noir red wines made by malolactic fermentation were studied for studying differences in their chemical profiles with help of a wide spectrum of grape -based and other chemical compounds used in winemaking. Determinations were made with capillary electrophoresis, liquid chromatography, and spectrometry to investigate carbohydrates, organic acids, aldehydes, anthocyanins, phenolic compounds, inorganic anions, and metals. In addition, tot-N, tot-S, and tot-P in the wines were examined. The wine products showed different profiles of carbohydrates, organic acids, phenolic compounds, and minerals. Especially, saccharose (max. 0.21 g/L), rhamnose (max. 0.45 g/L), fructose (max. 1.9 g/L), phosphate (max 1.4 g/L), and potassium (max 1.1 g/L) quantities were extremely high in some wines. The results also showed that yeast fermentation in winemaking agitated high production of lactic (max 5.7 g/L) and tartaric (max 1.7 g/L) acids. The red wines processed by cold maceration and natural fermentation gave similar profiles. Only one of the Pinot Noir wines entirely differentiated from the others with comparison of carbohydrates and organic acids.

Capillary electrophoresis with UV detection was used to separate tramadol (TR), a centrally acting analgesic, and its five phase I (M1, M2, M3, M4, M5) and three phase II metabolites (glucuronides of M1, M4 and M5). Several factors were evaluated in optimisation of the separation: pH and composition of the background electrolyte and the influence of a micellar modifier, sodium dodecyl sulfate. Baseline separation of TR and all the analytes was obtained with use of 65 mM tetraborate electrolyte solution at pH 10.65. The lowest concentrations of the analytes that could be detected were below 1 microM for the O-methylated, below 2 microM for the phenolic and ca. 7 microM for the glucuronide metabolites. The suitability of the method for screening of real samples was tested with an authentic urine sample collected after a single oral dose (50 mg) of TR. After purification and five-fold concentration of the sample (solid-phase extraction with Oasis MCX cartridges), the parent drug TR and its metabolites M1, M1G, M5 and M5G were easily detected, in comparison with standards, in an interference-free area of the electropherogram. Diastereomeric separation of TR glucuronides in in vitro samples was achieved with 10 mM ammonium acetate-100 mM formic acid electrolyte solution at pH 2.75 and with basic micellar 25 mM tetraborate-70 mM SDS electrolyte solution at pH 10.45. Both separations showed that glucuronidation in vitro produces glucuronide diastereomers in different amounts. The authentic TR urine sample was also analysed by micellar method, but unambiguous identification of the glucuronide diastereomers was not achieved owing to many interferences.

Two capillary electrophoretic analysis methods are presented; one optimized for the analysis of Br− and the other for determination of K+ in groundwaters of high conductivity. The water sampling was performed from the planned final disposal facility area for spent nuclear fuel at Olkiluoto in the municipality of Eurajoki, Finland. Bromide was analysed in an acidic electrolyte solution containing 5 mM formic acid and 42 mM NaCl (pH 3.5) and using direct UV detection (200 nm). Sample stacking was needed for the preconcentration. Potassium was analysed at pH 4.5 using imidazole-18-crown-6 ether solution. The accuracies of the Br− and K+ methods were tested using laboratory-made reference sample mixtures with high salt concentration. In the Br− analyses, the limits of detection and determination were 0.1 and 1 mg L−1, respectively. The developed CE analysis for K+ in saline water was repeatable (RSD% 14.5–18.0) and the detection and the determination limits were 0.5 and 2.0 mg L−1, respectively. The interlaboratory results showed that CE measurements of Br− and K+ were compatible with those made with traditional solvent chemistry techniques.

Nonaqueous capillary electrophoretic separation of a group of flavonoids (quercetin, myricetin, catechin, epicatechin) and resveratrol in wine was investigated in methanol at high pH. Malonate background electrolyte (pH* 13.5, ionic strength I = 14.2 mmol/L) provided highly repeatable separations of the analytes. Tests of untreated and coated (poly(glycidylmethacrylate-co-N-vinylpyrrolidone)) capillaries showed the analysis to be faster (6.5 min vs. 25 min) and the repeatability better in the coated capillaries. The coating procedure was simple and highly repeatable and the coating was stable during 40-45 runs. Determination of the last migrating peaks (epicatechin, resveratrol and catechin) was achieved merely by evaporating the wine samples and reconstituting the residue in methanol. For determination of the first migrating peaks (quercetin and myricetin) the samples were submitted to solid-phase extraction in C8 cartridges.

The stability of three complexing agents, HEDP, CDTA and DTPMP, in the SC-1 bath was determined. The feasibility of using capillary electrophoresis (CE) and electrospray ionization mass spectrometry (ESI/MS) for such studies was assessed. CE was employed for stability studies and ESI/MS was used to analyze small complexing agent concentrations relevant to residue studies. Chem. residues were studied by secondary ion mass spectrometry.

2,3-Pyrazinedicarboxylic acid (PZDA), 2,6-pyridinedicarboxylic acid (PDA) and 2,3-pyridinedicarboxylic acid (QUIN) solutions were studied as background electrolytes (BGEs) in the capillary electrophoretic analysis of dicarboxylic acids in aerosol particles with indirect UV detection. The BGEs were selected on the basis of similarity in structure with the analytes so that mobilities would be compatible. Optimised pH values for PZDA, PDA and QUIN solutions were 10.6, 11.0 and 10.2, respectively. Myristyltrimethylammonium hydroxide and myristyltrimethylammonium bromide were added to reverse the electroosmotic flow in the solutions in the direction of anode to enable fast anion detection. Separation was obtained for nine dicarboxylic acids (C2-C10) differing in the number of CH2 groups in their skeleton. The electrophoretic mobilities were determined to lie in the range 3.0 x 10(-4)-7.0 x 10(-4) cm2 V(-1) s(-1). The relative standard deviations (RSDs) for the absolute migration times of the analytes were mostly less than 0.5% (n=6) in PZDA solution. In PDA solution the within-day and day-to-day RSD values for migration were less than 1% and between 2 and 4%, respectively. Peak heights and areas mostly deviated between 1 and 15% in both PZDA and PDA solutions. Detection limits ranged between 1 and 5 mg/l. Methods were applied to the analysis of dicarboxylic acids isolated from aerosol particles.

A contactless conductivity detector integrated into the capillary cassette of Agilent 3DCE equipment is described. The detector is user-friendly, compact and easily modified. The UV detector of the 3DCE equipment is available parallel with the contactless conductivity detector increasing the detection power. Two electrolyte solutions, 2-(N-morpholino)ethanesulfonic acid–histidine solution (20 mM, pH 6.0) and ammonium acetate (10 mM, pH 4.0), were used as the separation media for inorganic cations and organic catecholamines, respectively. The detection limit for all metal cations except barium was under 0.5 mg/l, and that for four catecholamines was ca. 10 mg/l. This last value was the same order of magnitude as achieved with parallel UV detection.

This study presents the optimization of a microemulsion electrokinetic chromatographic (MEEKC) electrolyte solution by using UV detection and with the method, simultaneous separations of chemically, biochemically and pharmaceutically related anionic and cationic compounds. Representatives of the compound groups were from isoflavonoids, benzodiazepines, metanephrines, diuretics and peptide hormones. The MEEKC separations under basic conditions were first optimized using a two-component isoflavonoid mixture as the sample and an electrolyte containing 10 mM tetraborate as the main buffer (pH 9.5). The stable microemulsion phase was adjusted with various amounts of octane, 1-butanol and sodium dodecyl sulfate (SDS). An only acidified electrolyte solution used in the study was made of phosphoric acid (pH 1.8) containing octane, SDS and ethyl acetate. The analyses with isoflavonoids showed that electrophoretic mobilities of the investigated compounds were highly related to the concentrations of SDS and 1-butanol with linear and parabolic correlation, respectively. However, addition of octane gave linear correlation only at low concentrations. In most cases four to six structurally related compounds and even 13 diuretics with various polar properties were separated from each other in basic microemulsion medium. The acidified MEEKC electrolyte gave good resolution for anionic metanephrines.

The capillary electrophoresis (CE) study was focused on quantifying glycohemoglobin A 1c , HbA 1c , in whole blood samples of patients suffering diabetes mellitus. The results showed that dynamic polyionic coating of the capillary made the method very reproducible. The precision evaluation, method comparison and bias estimation in CE were performed during 20 days with patient blood samples and with four control samples. The influence of the storage time and temperature on the glycohemoglobin levels were also tested. High resolution in CE could be used to show evidences of the ageing of the samples stored at -70 °C. The results showed that the ageing peak was not originated from HbA 1c , because it did not affect the HbA 1c level which was in balance with the results of fresh samples measured with immunoassay. The HbA 1c % values of blood samples of 105 patients measured with the CE technique varied between 3.6 and 11.8 and they were approximately 2-3% lower than measured with immunoassay. The correlation (R 2 ) of CE results with immunoassay and HPLC results were 0.962 and 0.781, respectively.

Catecholamines were analysed in aqueous and alcoholic non-aqueous solutions by capillary electrophoresis and capillary electrophoresis-mass spectrometry using sheathless nanospray coupling. Decreases in the electrophoretic mobilities of the catecholamines and in the electroosmotic mobilities were observed from water to 1-propanol. Separations were more efficient in all non-aqueous media than in water. The diffusion coefficients of the catecholamines in the different media were determined. The solvent had little effect on the sensitivity of the UV or MS detection. Both methods were successfully applied to the analysis of urine samples.

This paper demonstrates the use of the first on-line capillary electrophoresis instrument with continuously flowing electrolyte solutions and sequentially applied sample introduction. The system was used in on-line determination of chloride, sulphate and carbonate concentrations of process waters at a pulp mill. The module constructed for on-line feedings of the solvents is described. Separations were performed in a pyromellitic acid-hexamethonium hydroxide-triethanol amine mixture at pH 7.7 with indirect-UV detection at 254 nm. Two standard mixtures were used to show the repeatability of the analysis and to estimate the accuracy of the on-line system. The analytes could be separated within 240 s. Sampling from a pulp machine could be accomplished on-line at 6 minute intervals. On-line tests gave a limit of detection and a limit of determination in the low mg/L range.

The aim of this work was to determine inorganic ions from natural waters by capillary electrophoresis (CE) and to compare the results obtained with those measured with conventional solvent chemistry techniques. The project was part of a larger CE study, during which we measured inorganic ions from some lake and river systems and groundwaters in Southern Finland. Results obtained from contaminated Finnish waters were compared with samples from the River Rhine in the Düsseldorf area. Two CE methods were used for analysis: one for determination of chloride, sulfate, nitrite and nitrate at pH 7.7 and the other for ammonium, potassium, calcium, sodium and magnesium at pH 3.6, both methods using identification based on indirect UV detection. Two separation methods were used in order to prevent complex formation of metals with sulfate, hydroxide and decomposed organic matter present in the environmental samples. On the basis of the CE studies dilution was needed for those samples having more than 100 mg/l of sulfate, chloride, calcium and sodium. On average, the natural waters in the study contained ammonium, magnesium, sodium, potassium and calcium below 0.3, 20, 200, 20, and 200 mg/l, respectively. The concentrations of chloride, sulfate, nitrite and nitrate were below 20, 100, 10, and 10 mg/l, respectively. Correlation of the CE results with those acquired by titration, atomic absorption spectrometry, ion chromatography and flow injection analysis were obtained; R2 values for the comparison tests varied from 0.8816 to 0.9994 depending on the ion. The repeatabilities of the anion and cation CE methods were tested using laboratory-made reference sample mixtures with high and low salt concentration