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In this study we investigated the underlying mechanisms of coffee stain formation on paper – a porous substrate. When a drop of aqueous liquid containing dispersed materials dries on paper, the faster water evaporation rate at the edge of the drop drives the redistribution of the dispersed materials to the edge of the drop-covered area on paper. Deegan׳s discovery has been accepted as the “coffee ring” phenomenon, which has wide implications. However, stains left by dried aqueous liquids on paper are not always ring-shaped. This is because, besides Deegan׳s coffee ring effect, the transport of dispersed materials in porous media is affected by chromatographic and filtration effects, which are highly dependent upon the properties of the substrates. In this work we clarify the influences of different mechanisms to the dispersed materials redistribution in paper. [ABSTRACT FROM AUTHOR]

Abstract: A quick and direct method for identifying organic components of papers in library and archival collections with minimal destructive sampling is needed for preservation, forensic, and general purposes. Direct analysis in real time mass spectrometry (DART-MS) is used for characterizing 16 reference papers of known manufacture in terms of their pulp composition and pitch contaminants. Unique mass spectra are obtained from bleached kraft, chemithermomechanical, and stone groundwood pulp papers in real time without extractions, derivatizations, chromatographic separations, and other time- and chemical-consuming sample preparations. Phytosteroids are volatilized from bleached hardwood kraft but not from bleached softwood kraft papers, which differentiates the two of them. The kraft papers are in turn differentiated from chemithermomechanical pulp papers by lignin-derived thermolyis products: syringyl products arise from hardwood, but guaiacyl and coumaryl products arise from softwood, chemithermomechanical pulp papers. Stone groundwood papers contain a number of extractives that are volatilized, which serve to differentiate them from all the other papers. Papers that contain rosin vs. alkyl ketene dimer (AKD) sizings are immediately differentiated. The DART-MS methodology is fast and simple, and the spectra are repeatable. Microsamples as small as ∼10μg tweezed from the paper surface may be analyzed. These benchmark spectra are the prelude to further applications of DART-MS in paper research and the beginning of the development of a searchable library of DART-MS spectra of printing and writing papers by the Library of Congress. [Copyright &y& Elsevier]

Abstract: The efficiency of several lab scale treatments (aerobic, anaerobic and ozone or combination of these) was evaluated using two packaging board mill whitewaters. The effect of the different treatments on the elimination of the organic load, the chemical oxygen demand (COD) and the toxicity was tested as well as the relationship between these parameters. Biocides, phenolic compounds, surfactants, plasticiziers and wood extractives were identified in untreated and treated whitewaters by liquid chromatography coupled with mass spectrometry (LC–MS) or gas chromatography coupled with mass spectrometry (GC–MS). A strong dependency on the water type and treatment efficiency was observed, being the combination of anaerobic and aerobic treatments the best option to reduce the organic contaminants in these waters, although in some cases, the toxicity did not decrease. However, ozone as post-treatment permitted a further reduction of organic compounds, toxicity and COD. [Copyright &y& Elsevier]

Highlights: [•] Improvement of the direct quantification with analytical pyrolysis. [•] Optimization of the chromatographic parameters after pyrolysis of cationic starch. [•] Quantification of cationic starches in cellulose matrixes. [•] Validation of the cationic starch quantification in paper samples. [ABSTRACT FROM AUTHOR]

This paper describes a new approach for the massive production of electrochemical paper-based analytical devices (ePADs). These devices are fully fabricated by screen-printing technology and consist of a lineal microfluidic channel delimited by hydrophobic walls (patterned with diluted ultraviolet screen-printing ink in chromatographic paper grade 4) and a three-electrode system (printed with carbon and/or Ag/AgCl conductive inks). The printing process was characterised and optimized for pattern each layer with only one squeeze sweep. These ePADs were used as transducers to develop a glucose biosensor. Ionic strength/pH buffering salts, electrochemical mediator (ferricyanide) and enzyme (glucose dehydrogenase FAD-dependent) were separately stored along the microfluidic channel in order to be successively dissolved and mixed after the sample dropping at the entrance. The analyses required only 10 µl and the biosensors showed good reproducibility (RSD = 6.2%, n = 10) and sensitivity (0.426 C/M cm 2 ), wide linear range (0.5–50 mM; r 2 = 0.999) and low limit of detection (0.33 mM). Furthermore, the new biosensor was applied for glucose determination in five commercial soft-drinks without any sample treatment before the analysis. These samples were also analysed with a commercial enzymatic-kit assay. The results indicated that both methods provide accurate results. [ABSTRACT FROM AUTHOR]

This study presents the research on the chemical analysis and genotoxicity of 28 virgin/recycled paper products in food-contact use. In the chemical analysis, paper products were extracted by reflux with ethanol, and analyzed by gas chromatography/mass spectrometry. 4,4′-bis(dimethylamino)benzophenone (Michler''s ketone: MK), 4,4′-bis(diethylamino)benzophenone (DEAB), 4-(dimethylamino)benzophenone (DMAB) and bisphenol A (BPA) were found characteristically in recycled products. Seventy-five percent of the recycled paper products contained MK (1.7–12 μg/g), 67% contained DEAB (0.64–10 μ g/g), 33% contained DMAB (0.68–0.9 μg/g) and 67% contained BPA (0.19–26 μg/g). Although, BPA was also detected in virgin paper products, the detection levels in the recycled products were ten or more times higher than those in the virgin products. The genotoxicity of paper and paperboard extracts and compounds found in them were investigated by Rec-assay and comet assay. Of the 28 products tested by Rec-assay using Bacillus subtilis, 13 possessed DNA-damaging activity. More recycled than virgin products (75% against 25%) exhibited such activity, which, of the compounds, was observed in BPA, 1,2-benzisothiazoline-3-one (BIT), 2-(thiocyanomethylthio)benzothiazole, 2,4,5,6-tetrachloro-isophthalonitrile, 2,4,6-trichlorophenol (TCP), and pentachlorophenol. The critical toxicant in one virgin paper product was concluded to be BIT. Eight samples with DNA-damaging activity were also tested by comet assay using HL-60 cells; six induced comet cells significantly (five times or higher than the control) without a decrease of viable cells. TCP, BZ, DEAB, and BIT also caused a slight increase in comet cells. In conclusion, we showed that most recycled paper products contain chemicals such as MK, DEAB, DMAB, and BPA, and possess genotoxicity. However, the levels of the chemicals in the recycled products could not explain their genotoxic effects. [Copyright &y& Elsevier]

New psychoactive substances (NPS) have been associated with fatalities and severe injuries in a number of cases in the United States and have led investigators to rethink traditional drug monitoring protocols. Of particular interest are the variable phenethylamine chemical structures known as 'NBOMes', which pose an emerging threat to public health with incidence steadily growing over the past decade. In this study, direct sample analysis (DSA)-time of flight mass spectrometry was employed to leverage rapid and sensitive ambient ionization mass spectrometry without chromatographic separation as verified with an authentic case sample. Samples for method development were prepared at Boston University School of Medicine's Biomedical Forensic Sciences program (Boston, MA) and analyzed at the State of Maine Health and Environmental Testing Laboratory's Forensic Chemistry Section (Augusta, ME). Preliminary method development work was performed at the University of Central Florida (Orlando, FL). DSA without any extraction step in addition to the evaluation of methanol, dichloromethane and hexane extractions were conducted. Methanol was found to not be a suitable extraction solvent for DSA analysis of these compounds. For the screening of NBOMe designer drug variables on blotter paper, DSA-TOFMS was successful at reducing analysis time to ∼15s per sample, for qualitative identification for the selected analytes of interest. The analysis of an authentic forensic case sample by DSA-TOFMS using the method development parameters demonstrates its utility in forensic laboratories. 25C-NBOMe was identified with an exact mass accuracy of 0.60ppm. [ABSTRACT FROM AUTHOR]

Abstract: Pyrolysis-gas chromatography (Py-GC) has been applied to the evaluation of the deteriorated acidic paper in old books. A tiny piece (ca. 0.25mg) of deteriorated paper was subjected to Py-GC measurement at 300°C pyrolysis temperature. Levoglucosan and its dehydrated form levoglucosenone were typical degradation products while a recent control paper gave rise mainly to levoglucosan. The relative yield of levoglucosenone was much higher for the paper sample taken at the heavily deteriorated marginal part than that in the center of the same page of the old book. Accordingly, levoglucosenone observed in the pyrogram can be used as a marker to evaluate the degree of the deterioration of the acidic paper. The formation of levoglucosenone can be attributed to the slow deterioration process of paper, in which dehydration reaction play an important roll accompanied by the chain scission of cellulose. The Py-GC method for paper evaluation was also applied to clarify the effect of storage conditions and chemical compositions of paper materials to their deterioration processes. [Copyright &y& Elsevier]

Although nucleic acid amplification test (NAT) is widely used for pathogen detection, rapid NAT systems that do not require special and expensive instruments must be developed in order to enable point of care (POC)-NATs, which contribute to early initiation of treatment. As a POC-NAT system, Kaneka DNA chromatography chip (KDCC), developed using DNA tag-bound primer through modified substance, was shown to be suitable for POC testing, due to the rapid detection time, simple procedures, and low manufacturing costs. However, owing to some modifications in primer, the detection performance and amplification speed were shown to be reduced when using KDCC, counteracting the increased speed of detection. To solve these issues and improve the speed of this NAT system, we investigated a better modification substance for KDCC. Here, azobenzene-modified primers were shown to have the highest amplification speed and detection performance in KDCC, of all modifications tested in this study, showing 10–100-fold lower detection limit but maintaining the same reaction time. Additionally, rapid herpes simplex virus detection system with azobenzene modified primers was developed. We believed that this breakthrough will contribute toward enabling greater utilization of POC-NATs for medical care, especially in developing countries and clinics. [ABSTRACT FROM AUTHOR]

A cost-effective microfluidic paper analysis device (μPAD) was developed with a special Z-folding design for controlling the fluidic flowing and substrate transportation. This presented μPAD can be easily fabricated through wax printing by using a solid ink printer which deposits wax onto the surface of a chromatographic paper, and then baked on a hotplate by penetrating the molten wax into the paper to create a hydrophobic barrier. After μPAD fabrication, liquid control and substrate transportation can be easily carried out by twice folding the μPAD following Z shape. The Z folding made two separated reagent holding zone connected while the detection reaction occurred with the connection. In this paper, a pathogens detection indicated by ATP quantification was took as a proof-in-principle application of using this presented μPAD, the limit of detection (LOD) was 1 μM for ATP detection and 2.6×10 7 CFU/mL for Salmonella live cell detection, which showed a great potential for Point-of-Care Testing (POCT) applications. [ABSTRACT FROM AUTHOR]

Paper chromatography was a big breakthrough in the early of 20th century but it is rarely used due to the long separation time and the diffusion on the sample spots. In this work, for the first time, a paper-based chemiluminescence (CL) analytical device combined with paper chromatography was developed for the determination of dichlorvos (DDV) in vegetables without complicated sample pretreatment. The paper chromatography separation procedure can be accomplished in 12min on a paper support (0.8×7.0cm2) by using 5µL sample spotted on it. After sample developing, the detection area (0.8×1.0cm2) was cut and inserted between two layers of water-impermeable single-sided adhesive tapes. The paper-based chip was made by attaching the middle layer of paper onto the bottom layer. Then it was covered by another tape layer, which was patterned by the cutting method to form a square hole (0.8×1.0cm2) in it. 10μL mixed solution of luminol and H2O2 was dropped on the detection area to produce CL. A linear relationship was obtained between the CL intensity and the concentrations of DDV in the range between 10.0ngmL−1 and 1.0μgmL−1and the detection limit was 3.6ngmL−1. Water-soluble metal ions and vitamins can be developed at different spatial locations relative to DDV, eliminating interference with DDV during detection. The paper-based chromatographic chip can be successfully used for the determination of DDV without complicated sample preparation in vegetables. This study should, therefore, be suitable for rapid and sensitive detection of trace levels of organophosphate pesticides in environmental and food samples. [ABSTRACT FROM AUTHOR]

Background: Fingertip prick whole blood collection on chromatography paper is amenable to high-throughput fatty acid (FA) profiling for large clinical and field studies. However, sample storage is problematic because highly unsaturated FAs (HUFAs) in erythrocytes rapidly degrade in samples stored at -20°C. Objective: The aim of the current study was to determine the mechanism of HUFA degradation and to develop prevention protocols. Methods: Free fatty acid (FFA) standards and whole blood reference material from a single participant were used to examine sample storage at -20°C for up to 90 d in triplicate. Iron chelation with deferoxamine (0-5000 µg), antioxidant protection with butylated hydroxytoluene (50 µg), cryopreservation with glycerol, and blood drying were examined using whole blood on chromatography strips. Biological replicate blood samples from additional participants (n = 6) with a range of ω-3 (n-3) HUFA concentrations were similarly assessed. Results: FFAs were relatively stable when stored on chromatography strips at -20°C. Glycerol treatment prevented HUFA degradation in whole blood reference material for 30 d (45 ± 0.4 to 46.8 ± 0.1, means ± SDs) compared to untreated saline controls (45.9 ± 1.0 to 6.8 ± 0.2). Pretreatment of paper for blood spots with deferoxamine and drying blood before storage slowed, but not entirely prevented, HUFA degradation over 30 d to 22% and 19% below baseline, respectively, compared to 86-92% in the controls. Protection against HUFA degradation with blood drying and glycerol treatment was confirmed in the biological replicate study and confirmed by prevention of cell lysis. Conclusions: HUFA degradation during storage at -20°C appears to be due to hemolysis and subsequent iron-initiated peroxidation. This degradation may be prevented by glycerol, iron chelation, and/or dried blood spotting. A more thorough understanding of methods to prevent degradation during storage is critical with increasing use of FA profiling in large clinical studies. [ABSTRACT FROM AUTHOR]

Natural killer (NK) cells are immune cells that defend against viral infections and cancer and are used in cancer immunotherapies. Subpopulations of NK cells include CD56dim and CD56bright which either produce cytokines or cytotoxically kill cells directly. The absolute number and proportion of these cells in peripheral blood are tied to proper immune function. Current methods of cytokine detection and proportion of NK cell subpopulations require fluorescent dyes and highly specialized equipment, e.g., flow cytometry, thus rapid cell quantification and subpopulation analysis are needed in the clinical setting. Here, a smartphone-based device and a two-component paper microfluidic chip were used towards identifying NK cell subpopulation and inflammatory markers. One unit measured flow velocity via smartphone-captured video, determining cytokine (IL-2) and total NK cell concentrations in undiluted buffy coat blood samples. The other, single flow lane unit performs spatial separation of CD56dim and CD56bright and cells over its length using differential binding of anti-CD56 nanoparticles. A smartphone microscope combined with cloud-based machine learning predictive modeling (utilizing a random forest classification algorithm) analyzed both flow data and NK cell subpopulation differentiation. Limits of detection for cytokine and cell concentrations were 98 IU/mL and 68 cells/mL, respectively, and cell subpopulation analysis showed 89% accuracy. • First smartphone-based paper microfluidic cell chromatography that can identify cell subpopulation. • Machine learning predictive modeling for NK cell subpopulation differentiation. • Integration of both cell chromatography and flow rate analysis on a single platform. • Potential application to many other cytokines and cell subpopulation analyses. [ABSTRACT FROM AUTHOR]

Abstract: Environment-responsive membranes were prepared by coating filter paper with poly (N-vinylcaprolactam) hydrogel. These membranes could be made to switch between hydrophobic and hydrophilic states in a reversible manner by the addition or removal of lyotropic salts. The effects of polymer loading and salt concentration on hydraulic permeability and human immunoglobulin G (hIgG) binding property of these membranes were studied. A candidate membrane possessing high hydraulic permeability and hIgG binding property was selected for carrying out protein purification experiments. This membrane demonstrated selective antibody binding, and could be used for hIgG purification from simulated cell culture supernatant. [Copyright &y& Elsevier]

Abstract: Results presented in this paper demonstrate that time of flight secondary ion mass spectrometry (TOF-SIMS) can be used for the analysis of ballpoint pen inks producing mass spectra that were highly characteristic of the constituent dyes and inorganic substances used in their formulations. Analysis was performed directly off the substrate (typically document paper) containing the ink with no interference from the background matrix. The resultant spectra were highly characteristic of the ink formulation and could be used to confidently discriminate between different inks. No extraction or complicated sample preparation was necessary which ensures the integrity of the document under examination. This is not only important in forensic applications but also indicates the potential for the application of this technique to the analysis of inks on documents of historical or archaeological significance. TOF-SIMS was also shown to be capable of analysing ink containing a mixture of dyes, initially separated by thin-layer chromatography, directly on the chromatographic material. [Copyright &y& Elsevier]

Two extracellular alkalistable 1,4-β-d-glucan-4-glucanohydrolase (EC 3.2.1.4) fractions, namely Endo A and Endo B were separated from the culture filtrate of an alkalotolerant Fusarium strain by gel chromatography on Bio Gel P-100 column. The viscometric characterization of enzyme indicated that the Endo B was 1.9 times more random in action as compared to Endo A. Both the endoglucanases showed comparable patterns of their ability to release short fibers in the reaction mixture when filter paper was used as the substrate. The average size of released short fibers was determined by scanning electron microscopy ranged between 20 and 100 μm. Adsorption characteristics of the endoglucanases indicated that the enzyme complex acts prominently at the surface of substrate rather than at their cracked edges. The X-ray diffractograms showed that the crystallinity of the substrates does not vary significantly in the initial stages of the enzymatic action. The extracellular enzyme preparation was found to be suitable for deinking of mixed office waste papers. The enzyme treatment resulted in the increase in brightness with the reduction in ink counts of the recycled paper. Based on the distinct properties of endoglucanases a probable mechanism of enzymatic deinking process is presented schematically. [Copyright &y& Elsevier]

Abstract: Residual lignins were isolated from eucalypt kraft pulps by enzymatic hydrolysis of cellulose followed by purification using a combination of proteinase hydrolysis and solvent extraction. The residual lignins isolated from brown (unbleached) and totally chlorine free (TCF) bleached pulps were analyzed by Fourier-transform infrared (FT-IR) spectroscopy and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), and compared with eucalypt milled-wood lignin and kraft lignin. The lignin in eucalypt wood and pulps showed a strong predominance of syringyl (S) over guaiacyl (G) units. The strongest lignin modification was observed in the kraft lignin recovered from the alkaline pulping liquor. The chemical composition of the residual lignin from pulp was closer to milled-wood lignin than to the kraft lignin, indicating that most of the lignin modified during pulping was released to the cooking liquor. During TCF bleaching of pulp, which included oxygen delignification and peroxide stages, modifications of lignin were produced resulting in increased amount of non-conjugated carbonyl groups. We concluded that residual lignin in eucalypt kraft pulp reflects native lignin moieties entrapped into the cellulosic network thus partially avoiding their attack by chemical reagents, although different modifications are produced during the bleaching stages. [Copyright &y& Elsevier]

Abstract: Chlorinated paraffins (also called polychlorinated n-alkanes — PCAs) are a class of industrial chemicals comprising chlorinated straight chain hydrocarbons. They have a wide range of applications and are now found in a range of environmental compartments. We analysed a total of 25 human milk-fat samples, donated by 18 individuals from the urban London and more rural Lancaster areas in the UK, for short chain PCAs (C10–C13 sPCAs) and medium chain PCAs (C14–C17 mPCAs), using gas chromatography–ECNI high-resolution mass spectrometry. Our study confirms that trace quantities of PCAs can reach human milk-fat. sPCAs were detected in all but four samples, while mPCAs were detected in all samples. The median sPCA concentration was 180 ng/g fat (range of 49 to 820 ng/g fat — detected values only) and the median mPCA concentration was 21 ng/g fat (range of 6.2 to 320 ng/g fat). No differences were noted in ranges of observed values for either sPCAs or mPCAs between samples from London and Lancaster. Most samples also exhibited similar patterns of sPCAs and mPCAs. One sample exhibited a different pattern for sPCAs and mPCAs, an observation that may be related to differences in exposure or biological factors for this individual. [Copyright &y& Elsevier]

Complex systems exist widely, including medicines from natural products, functional foods, and biological samples. The biological activity of complex systems is often the result of the synergistic effect of multiple components. In the quality evaluation of complex samples, multicomponent quantitative analysis (MCQA) is usually needed. To overcome the difficulty in obtaining standard products, scholars have proposed achieving MCQA through the "single standard to determine multiple components (SSDMC)" approach. This method has been used in the determination of multicomponent content in natural source drugs and the analysis of impurities in chemical drugs and has been included in the Chinese Pharmacopoeia. Depending on a convenient (ultra) high-performance liquid chromatography method, how can the repeatability and robustness of the MCQA method be improved? How can the chromatography conditions be optimized to improve the number of quantitative components? How can computer software technology be introduced to improve the efficiency of multicomponent analysis (MCA)? These are the key problems that remain to be solved in practical MCQA. First, this review article summarizes the calculation methods of relative correction factors in the SSDMC approach in the past five years, as well as the method robustness and accuracy evaluation. Second, it also summarizes methods to improve peak capacity and quantitative accuracy in MCA, including column selection and two-dimensional chromatographic analysis technology. Finally, computer software technologies for predicting chromatographic conditions and analytical parameters are introduced, which provides an idea for intelligent method development in MCA. This paper aims to provide methodological ideas for the improvement of complex system analysis, especially MCQA. [Display omitted] SSDMC: single standard to determine multiple components; RCF: relative correction factor; 2D-LC: Two dimensional liquid chromatography; CSASS: complex sample analysis software system; QSRR: quantitative structure-retention relationship. • Reviewing development progress of SSDMC method in complex system analysis. • Reviewing chromatographic columns selection and 2D-LC analysis method construction. • Summarizing computer-aided techniques for predicting chromatographic analytical parameters. • Predicting future development direction of MCQA. [ABSTRACT FROM AUTHOR]

The formation of sewage sludge in the wastewater treatment process is an inevitable component of this process. To manage this waste in an ecological manner, the qualitative and quantitative composition of the sludge should be considered. Studies of sewage sludge clearly indicate the presence of micropollutants in raw sewage, such as residues of pharmaceuticals. This broad group of compounds differs in terms of physicochemical properties and the ability to adsorb to sludge. Some of them are significantly reduced in the treatment process. There is a large group of hydrophilic compounds that are only slightly reduced and thus leave the treatment plant together with the treated sewage. Substances characterized by high adsorption to sewage sludge, such as endocrine compounds, may affect the possibility of its safe use. This paper focuses on the review of the methods of determination of antibiotics and endocrine disruptors in sewage sludge. Issues related to the selection of the sample type, the method of its preparation and the selection of the appropriate chromatographic analysis were discussed. The obtained data will make it possible to assess the safe use of sewage sludge in agriculture, which is important for the implementation of the circular economy in sewage sludge management. [ABSTRACT FROM AUTHOR]

The analysis of chlorinated paraffins (CPs) has become a major analytical challenge. GC-ECNI-HRMS coupling is often used to analyse and quantify them. However, the influence of certain GC and ECNI parameters on the responses of polychlorinated n -alkanes (PCAs), the dominant components of CPs, has hardly been studied. In this paper, we investigated not only the influence of GC column characteristics, but also oven, GC inlet and source temperatures for simultaneous analysis of PCAs with chain-length ranging from 10 up to 20 carbon atoms (PCAs–C 10-20). Particular attention was paid to the absolute response and PCA homologue group pattern obtained for a CP technical mixture. The optimum conditions for a wide homologue group determination were GC inlet, final gradient and ion source temperatures set at 220–240 °C, 340 °C and 200 °C. At the same time, a higher response was obtained with the Optima 5HT column compared to Optima 1 column, and with a length and film thickness of 12.5 m and 0.25 μm, respectively. The homologue group pattern of the technical mixture studied was significantly modified as a function of the source and GC inlet temperatures, film thickness and composition of the stationary phase. Here we recommend conditions that will improve the overall PCA pattern, in order to better characterise their occurrence in future environmental monitoring and exposure assessment. [Display omitted] • PCAs were detected up to C 20 using the optimised GC-ECNI-HRMS method. • Influence of GC and ECNI parameters on PCA patterns were revealed. • Ion source temperatures above 250 °C lead to possible formation of PCOs. • Degradation of heaviest PCAs may occur at elevated inlet source temperatures. [ABSTRACT FROM AUTHOR]

Bio-oils produced by direct thermal liquefaction often contain heavy components that hinder their utilization as a liquefaction medium. This paper reports a new approach to fractionate the liquefaction bio-oil into a light and a heavy fraction based on solvent extraction and temperature-swing regeneration. This approach is based on hot extraction (T ∼ 70 °C) of the light fraction of the oil with a suitable extraction solvent followed by cold (T ∼ 25 °C) de-mixing of the light fraction and the extraction solvent. In this paper, we (i) illustrate the selection of the extraction solvent and define the solvent properties required, (ii) demonstrate the potential of multistage extraction/regeneration for the bio-oil produced by direct thermal liquefaction, (iii) extend the concept to fractionate a petroleum crude oil, (iv) discuss the theoretical basis of the fractionation using polymer solution theory and, finally, (v) show a low energy requirement of the extraction process by means of process simulation, i.e., an equivalent of ∼1% of the biomass intake. [ABSTRACT FROM AUTHOR]

In this paper, we describe the development of a multicomponent lateral-flow assay based on an antibody–antigen reaction for the rapid and simultaneous detection of trace contaminants in water, including a heavy metal, algal toxin, antibiotic, hormone, and pesticide. The representative analytes chosen for the study were lead (Pb(II), microcystin–leucine–arginine (MC–LR), chloramphenicol (CAP), testosterone (T), and chlorothalonil (CTN). Five different antigens were immobilized separately in five test lines on a nitrocellulose membrane. The monoclonal antibodies specifically recognized the corresponding antigens, and there was no cross-reactivity between the antibodies in the detection assay. Samples or standards containing the five analytes were preincubated with the freeze-dried colloidal-gold-labeled monoclonal antibody conjugates to improve the sensitivity of the assay. The results were obtained within 20 min with a paper-based sensor. The cut-off values for the strip test were 4 ng/mL for Pb(II), 1 ng/mL for MC–LR, 0.1 ng/mL for CAP, 5 ng/mL for T, and 5 ng/mL for CTN. The assay was evaluated using spiked water samples, and the accuracy and reproducibility of the results were good. In summary, this lateral-flow device provides an effective and rapid method for the onsite detection of multiple contaminants in water samples, with no treatment or devices required. [ABSTRACT FROM AUTHOR]

Abstract: High throughput process development (HTPD) platforms provide time and resource effective solutions for optimization of resin as well as membrane based chromatography processes. They enable successful implementation of Quality by Design by allowing us to investigate more variables and wider ranges than would be possible using traditional lab-scale based experiments. This paper presents an investigation about non-specific protein adsorption that was found to occur on the membrane disks used in a commercially available high throughput device. Both qualitative as well as quantitative analytical tools were used in this investigation. Two biotherapeutic protein molecules, granulocyte colony stimulating factor (GCSF) and Transtuzumab were selected as model proteins in this study. Qualitative assessment was performed using Attenuated Total Reflectance Fourier-Transform Infrared Spectroscopy (ATR-FTIR), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). An empirical model based on contact angle measurement was developed for quantitative assessment of the amount of adsorbed protein. The results indicated that while significant non-specific adsorption was observed in case of highly hydrophobic GCSF molecule, adsorption was minimal in the case of Transtuzumab. The paper proposes a novel use of contact angle measurement for quantitative estimation of adsorbed protein. The study also highlights the importance of accounting for non-specific adsorption when using these HTPD devices. [Copyright &y& Elsevier]

Abstract: Membrane chromatography has emerged as a potential alternative to conventional packed bed chromatography with advantages including reduced hardware requirement, operational ease, and shorter processing time. Transport of molecules in such membranes is primarily driven by convection with very limited pore diffusion as compared to packed bed column chromatography resulting in increased mass transfer and quicker capture of the product and also allowing us to work at very high flow rates. While development of such a step is relatively simpler when compared to packed bed chromatography, it still involves optimization of the various parameters experimentally as a first step towards commercialization. This is often a time and resource intensive exercise. It is expected that companies have better understanding and control of their manufacturing processes. Biotech manufacturers, however, are under ever-increasing pressure to reduce the cost of development and commercialization of a biotech therapeutic. Use of miniaturization and automation in the form of high throughput process development (HTPD) offers a potential solution. In this paper, we address development of such a platform for membrane chromatography. The platform proposed in this paper has been successfully applied towards process development for purification of a biotech therapeutic, Granulocyte Colony Stimulating Factor (GCSF). Further, we have also validated the platform by comparing the results obtained with the HTPD platform (7µl membrane volume) against those obtained at the traditional laboratory scale (0.18mL membrane volume). Statistical analysis of the data has been performed to assess the strengths and limitations of the platform. [Copyright &y& Elsevier]

Disc membrane chromatography modules are widely used for laboratory-scale protein separations. These have high radial to axial aspect ratios, with the inlet and the outlet being located at the centre. This results in a huge variability in flow path lengths. Also, the radial velocity in the feed side header decreases very significantly in an outward direction, while that in the permeate side header increases in an inward direction. Therefore, the flow paths closer to the axis of the membrane disc have higher average velocity compared to those closer to the periphery. Consequently, the solute residence time distribution within the disc membrane chromatography module is very large, which results in broad flow-through and eluted peaks and early breakthrough of bound solutes. In this paper, we discuss a simple but effective solution to this problem which involves the incorporation of a flow directing layer (FDL) within the membrane module. The FDL could be placed either in the front or at the rear of the membrane disc. The presence of FDL results in equalization of path lengths within the module, leading to narrowing of residence time distribution, and thereby improvement in separation efficiency. Modules housing strong cation exchange membrane discs having two different bed volumes of 0.4 mL (40 mm diameter) and 4.7 mL (60 mm diameter) were designed and fabricated in-house. The impact of using FDL on both the front side (F-FDL) and the rear side (R-FDL) was investigated. The separation efficiency of the membrane modules was assessed using salt tracer experiments, breakthrough protein binding, and ternary protein separation carried out in the bind-and-elute mode. The results confirmed that the use of the FDL significantly enhanced the separation efficiency. In addition to membrane chromatography, this approach of using an FDL could be extended to other membrane disc based modules such as in-line and syringe filters and membrane reactors. • Improvement in membrane chromatography using a flow directing layer (FDL). • FDL resulted in flow path length equalization. • FDL decreased residence time distribution. • FDL increased breakthrough binding capacity. • FDL increased refolution multi-protein separation. [ABSTRACT FROM AUTHOR]

Abstract: A WHO position paper states that allergen immunotherapy is an effective treatment for allergic diseases, and well characterized allergens should be used in immunotherapy. The house dust mite is a major cause of allergic disease. However, the biological activity of the mite extracts currently used cannot be clearly determined, since these extracts contain various impurities. The use of recombinant allergens can avoid this problem. However, there remains a risk of contamination by other impurities, such as host cell-derived proteins (HCPs). Advanced purification techniques are thus required to remove these contaminants. C8/119S is a mutant of the major house dust mite allergen Der f 2, and is expressed and accumulated as an inclusion body in Escherichia coli. The C8/119S was refolded and purified through three column chromatography steps. Using this method, we could obtain about 2g of the purified C8/119S in one purification batch. This amount is equivalent to 100,000 of the maintenance doses required for immunotherapy based on the WHO position paper. The purity of the C8/119S was 99% or more. The antigenicity of HCPs in the C8/119S was examined by passive cutaneous anaphylaxis assays. When the C8/119S was administered at 40μg/kg, no local anaphylaxis was observed. C8/119S was thus highly purified with an extremely low level of impurities, and our procedure was shown to be an effective advanced production-scale purification process for this Der f 2 mutant. In this study, we established an advanced purification processes for C8/119S, then characterized the purified C8/119S and evaluated its purity. [ABSTRACT FROM AUTHOR]

Abstract: Micellar electrokinetic chromatography (MEKC), which can separate neutral analytes as well as charged analytes by the capillary electrophoretic technique, was developed in 1982 and the first paper was published in 1984. The authors’ group concentrated their effort into the characterization of MEKC as a separation technique until early 1990s. Most issues in MEKC separations were successfully solved and wide applicability of MEKC was verified in 1990s. In particular, sweeping, an on-line sample preconcentration technique, was very successful for the concentration of neutral analyte as well as ionic ones. In this paper, our studies on MEKC will be summarized from the personal viewpoint of the author. [Copyright &y& Elsevier]

Abstract: This contribution addresses the design and investigation of two hybrid enantioseparation processes including an enzymatic racemization step in order to enhance the overall performance. Complementary to part I where the manufacturing and the characterization of an amino acid racemase (EC 5.1.1.10) was emphasized [Würges, K., Petrusevska, K., Serci, S., Wilhelm, S., Wandrey, C., Seidel-Morgenstern, A., Elsner, M.P., Lütz, S., 2009. Enzyme-assisted physicochemical enantioseparation processes—part I: production and characterization of a recombinant amino acid racemase. J. Mol. Cat. B (in print), online available: doi:10.1016/j.molcatb.2008.10.006.], the work presented in this paper tends more towards developing a data base for potential process schemes for the manufacture of selected amino acids. The first proposed process concept (P-I) couples preferential crystallization (PC) and racemization for the production of l-asparagine (l-Asn) using racemic mixture of dl-asparagine (conglomerate-forming system) as a starting material, while the second concept (P-II) integrates chromatography and racemization for the preparation of l-methionine (l-Met) starting with racemic mixture of dl-methionine (compound-forming system). As mentioned in part I, a racemization unit, where the unwanted enantiomer will be converted into racemate, is incorporated into the hybrid processes for the sake of 100% yield, theoretically. Besides the basic investigation according to the solid–liquid equilibria, PC and chromatography, the focus of this paper is mainly on the kinetic studies of the racemization reaction. Initially, the solubility ternary phase diagrams of both examined systems were determined, leading into the idea of combination of the proposed process schemes. For P-I the concept of PC of l-Asn was experimentally proven and the kinetics of the racemization was examined for d- and l-Asn in water using purified lyophilizate (PL). Concerning P-II, for the chromatographic unit the impact on the separation of dl-Met on eremomycin based stationary phase using KPi buffer and MeOH as mobile phase was evaluated in terms of resolution and selectivity at three different temperatures by varying the content of methanol (MeOH) in the mobile phase and the pH. The experiments for determination of the racemization kinetics were done for a compromised parameter set using crude lyophilizate (CL). In both cases a Michaelis–Menten three-step model was used to describe the enzymatic reaction. [Copyright &y& Elsevier]

Abstract: Recombinant Volvariella volvacea endoglucanase 1 (EG1) and its catalytic module (EG1-CM) were obtained by expression in Pichia pastoris, purified by two-step chromatography, and the catalytic activities and binding capacities were compared. EG1 and EG1-CM exhibited very similar specific activities towards the soluble substrates carboxymethyl cellulose, lichenan and mannan, and insoluble H3PO4 acid-swollen cellulose, whereas the specific activities of EG1-CM towards the insoluble substrates α-cellulose, Avicel and filter paper were approximately 58, 43 and 38%, respectively compared to EG1. No increase in reducing sugar release was detected in the reaction mixture supernatants after 50h exposure of filter paper, Avicel or α-cellulose to EG1-CM, whereas increases in the total reducing sugar equivalents (i.e. reducing sugar released into solution together with new reducing ends generated in the cellulosic substrates) in reaction mixtures were observed after 1h. In reaction mixtures containing EG1, soluble reducing sugar equivalents were detected in supernatants after 3h incubation with the insoluble cellulosic substrates. EG1-CM did not adsorb to Avicel, and the binding capacities of EG1-CM towards filter paper and H3PO4 acid-swollen cellulose were 27.9–33.3% and 29.6–60.6%, respectively of values obtained with EG1 within the range of total added protein. In enzymatic deinking experiments, the ink removal rate in EG1-CM-treated samples was only slightly higher (∼8%), than that of untreated controls, whereas that of the EG1-treated samples was 100% higher. Bio-stoning of denim with EG1-CM resulted in increases of 48% and 40% in weight loss and indigo dye removal, respectively compared with untreated controls. These increases were considerably lower than the corresponding values of 219% and 133% obtained when samples were treated with EG1. [Copyright &y& Elsevier]

The study included one station close to a pollution source (depth 59m) and another far from polluted areas (depth 40m). Samples were analysed for organic chlorine, bromine and sulfur compounds. Samples taken with a corer were sliced to the layers of 0–1, 1–4, 4–7cm etc. down to the depth of 34cm. The dating was made with two independent methods, the 210Po method and with the soot particle counting method. The analyses were made with a multiresidue method. Gas chromatography was connected to low resolution mass spectrometry (LRMS) or to high resolution mass spectrometry (HRMS). A different extraction was applied to screen the possible occurrence of polysulfides. Typical chlorophenol and chlorohydrocarbon traces from chlorobleaching of pulp were non-detectable. Also PCDDs, PCDFs, PCBs and various organochloride pesticides, fire retardant residues PBDEs, PBDDs and PBDFs and polychlorinated phenyl salicylates were not detected. Instead, methylated dibenzothiophenes Me-DBTs and Di-Me-DBTs, typical traces of oil based defoamers used in e.g. paper mills were found in the surface layers of the polluted site. Polysulfides were analyzed from layers representing years 1955–1970 from the polluted site. The structures of five congeners were according to GC/MS dimethyl trisulfide, 1,2,3,4-tetrathiepane, pentathiane, 1,2,3,4-tetrathiane and 1,2,4,5-tetrathiepane. Many of the analyzed pollutants have not been reported earlier from Lake Ladoga. The only positive observations were from oil-based defoamers used in paper mills, and from polysulfides, which are either of natural origin or indicate a discharge in the 1950s and 1960s. Owing to the large spreadout and dilution, the concentrations are low even at moderate distances from the pollution centers. [Copyright &y& Elsevier]

Abstract: This paper reports on polycyclic aromatic hydrocarbons (PAHs) in the atmospheric particulate matter of Jawaharlal Nehru University campus, an urbanized site of New Delhi, India. Suspended particulate matter samples of 24h duration were collected on glass-fiber filter paper for four representative days in each month during January 2002 to December 2003. PAHs were extracted from filter papers using toluene with ultrasonication method and analysed. Quantitative measurements of polycyclic aromatic hydrocarbons (PAHs) were carried out using the gas chromatography technique. The annual average concentration of total PAHs were found to be 668±399 and 672±388ng/m3 in the years 2002 and 2003, respectively. The seasonal average concentrations were found to be maximum in winter and minimum during in the monsoon. The results of principal component analysis (PCA) indicate that diesel and gasoline driven vehicles are the principal sources of PAHs in all the seasons. In winter coal and wood combustion also significantly contribute to the PAH levels. [Copyright &y& Elsevier]

Abstract: Monitoring of ambient PM10 (particulate matter which passes through a size selective impactor inlet with a 50% efficiency cut-off at 10 μm aerodynamic diameter) has been done at residential (Kasba) and industrial (Cossipore) sites of an urban region of Kolkata during November 2003 to November 2004. The measurements have been performed once a week during the study period. PM10 mass concentrations ranged from 68.2 to 280.6 μg/m3 at a residential site and 62.4 to 401.2 μg/m3 at an industrial site. Metal constituents of ambient PM10 deposited on quartz microfibre filter papers were identified using Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES). Chromium (Cr), zinc (Zn), lead (Pb), cadmium (Cd), nickel (Ni), manganese (Mn) and iron (Fe) are the seven toxic trace metals quantified from the measured PM10 concentrations. Results identified zinc with maximum contribution of PM10 among measured metals having concentrations of 0.49 μg/m3 at the residential site, and 0.53 μg/m3 at the industrial site. The PAH (polycyclic aromatic hydrocarbon) compounds namely, fluoranthene (Fl), pyrene (Py), benzo(a)anthracene (BaA), benzo(b)fluoranthene (BbF) and benzo(a)pyrene (BaP) have been analyzed using gas chromatography. The major PAH compound at the monitoring sites was BbF with 0.03 μg/m3 at the residential site and 0.02 μg/m3 at the industrial site. Total carbon (TC), inorganic carbon (IC) and organic carbon (OC) of PM10 were analyzed using a carbon analyzer. Exposed quartz microfibre filter papers were also analyzed for water-soluble anions of fluoride (F−), chloride (Cl−), nitrate (NO3 −), phosphate (PO4 3−) and sulfate (SO4 2−) using ion chromatography. Sulfate was found in maximum concentration among anionic species with a value of 1.2 μg/m3 at the residential site, and 1.7 μg/m3 at the industrial site. Meteorological parameters such as wind speed, wind direction, rainfall, temperature and relative humidity were collected simultaneously during the sampling period from the Indian Meteorological Department, Kolkata. A simultaneous meteorological study was performed to assess the influence of air masses by measured meteorological parameters. Winter concentrations of PM10 and its chemical constituents were mainly higher than in other seasons, irrespective of the monitoring sites. It indicates a longer residence time of particulates in the atmosphere during winter due to low winds and low mixing height. Winter to monsoon ratio for PM10 is 1.6 and 2.3 for residential and industrial sites, respectively. Summer to monsoon ratio of PM10 observed in the study period was 1.3 for the residential site, and 1.4 for the industrial site. The higher particulate pollution in the industrial area may be attributed to resuspension of road dust, soil dust, automobile traffic and nearby industrial emissions. Spearman rank correlation coefficient analysis showed an inverse relationship between PM10 and its chemical constituents with wind speed, temperature, rainfall and relative humidity. [Copyright &y& Elsevier]

A composite chitosan–cellulose membrane was prepared by coating chitosan on filter paper. Physical properties of the composite membrane and its application in affinity membrane immunoadsorption (IgG to immobilized Protein A) were examined. The chitosan and porogen (polyethylene glycerol, PEG) contents in the chitosan preparation solution have a significant effect on porosity of the membrane and the flow rate of water through the membrane. The effect of the evaporation time (ET) of the solution after coating on the flow rate was also determined. The composite membrane with a relatively large flux (3.2 ml/min/cm2 at 12.5 psi) and approximately 1 μm pore size was prepared by using a 0.5% chitosan solution containing 15.0% PEG and evaporating the solution for 3 h at room temperature after coating. The obtained composite membrane provided tensile strength larger than the plain cellulose support, in both wet and dry states. The hydroxyl groups on the composite membrane were modified with an 11-atom spacer arm to link Protein A as an affinity ligand. For comparison, the plain filter paper was also linked with Protein A using the same method. The amount of Protein A immobilized was 1.36 and 6.29 mg/ml membrane on the plain filter paper and the composite membrane, respectively. The composite membrane provided a relatively high dynamic binding capacity of human IgG at 14.9 mg/ml membrane, which is four-fold higher than that of the plain filter paper. [Copyright &y& Elsevier]

Abstract A simple, rapid and cost-efficient method for determination of activity concentration of 90Sr in biological samples with an extraction chromatographic column (crown ether on teflon powder) and following counted by liquid scintillation counting was developed in this paper. The column retained most of 90Sr while almost all of matrix ions were removed during rinsing steps with 8M nitric acid and finally 90Sr was eluted with deionized water, the chemical recovery of strontium is greater than 60%, almost all of matrix ions were removed by the procedure we reported. Finally the uncertainty was evaluated and minimum detectable activity of this method is 1.28Bq/kg. Highlights • Preparation of crown ether chromatographic column based on teflon power in terms of cost-effective. • Develop a rapid and selective method for determination of 90Sr in biological samples with total analyzing time within 10 h. • The value of 90Sr determined by described was in good agreement with that of reference materials. • Assess the uncertainty and minimum detectable activity of whole procedure. [ABSTRACT FROM AUTHOR]

Heterogeneous combination flooding system composed of dispersed particle gel (DPG) and tetradecyl hydroxyl sulfo betaine (THSB) has been developed as a cost-effective EOR method due to highly beneficial synergistic behavior of improving both sweep efficiency and displacement efficiency. However, the combination flooding system suffered from surfactant loss and chromatographic separation which would raffect synergistic effect of chemical components for extra oil recovery. In this paper, static adsorption and dynamic adsorption of combination flooding system were systematically investigated. Additionally, effects of core permeability, DPG concentration and flow distance on chromatographic separation were also investigated by means of core flooding experiments. Static adsorption experiments indicated that after DPG particles and THSB surfactant were combined, adsorption of THSB surfactant on the quartz sand was lowered while the adsorption of DPG particles was improved, which was attributed to the interactions between DPG particles and THSB surfactant. Dynamic adsorption experiments showed that DPG particle could reduce the surfactant mobility and lead to increase of surfactant retention. Core flooding experiments confirmed that chromatographic separation phenomenon existed when combination flooding system flowed through porous media and the degree of separation phenomenon was lower than that of surfactant and polymer combination flooding system. Smaller surfactant losses, higher particle adsorption and lower chromatographic separation were all responsible for better synergistic behavior of heterogeneous combination flooding system. [ABSTRACT FROM AUTHOR]

Pemphigus foliaceus (PF) and its endemic form, Fogo Selvagem (FS), are characterized by subcorneal vesicles and pathogenic IgG autoantibodies directed against keratinocyte surface antigens. A major pool of FS antigen(s) remains bound to the insoluble epidermal envelope fraction. In this paper we demonstrate that this antigen(s) can be released From the envelope fraction by sonication. By immune precipitation four components can be detected, having molecular weights (MW) of 260, 80, 62, and 45 kD. The 260-kD component is lost by boiling or extraction with glycine HG! at pH 2.8. The major components appear to be the 80- and 62-kD poly-peptides. They chromatograph as a unit by gel filtration in 0.1% SDS, in the MW range of 115-120 kD. The FS antigen(s) appears to be cationic, forming insoluble complexes at low pH with SDS, and is labile to ammonium sulfate and freezing and thawing. It is unaffected by positive pressure concentration, 50% acetone precipitation, and reduction/alkylation. The FS antigen(s) is precipitated by all FS and nonendemic PE sera except those in complete clinical and serologic remission. The FS antigen(s) is also precipitated by 50% of pemphigus vulgaris but none of the bullous pemphigoid sera tested. All FS antigenic components are immunoprecipitated by IgG4 autoantibodies, but the IgG1 subclass from the same patients appear to immunoprecipitate only the 62-kD polypeptide. The ES antigen(s) is able to adsorb human autoantibodies against human desmoglein 1 (DG1), but not rabbit antisera against bovine DG1 or 2. This paper shows that physical stress, i.e., sonication, may be able to solubilize sufficient ES antigen(s) from the epidermal envelope fractions for further chemical characterization. The relationship of these PS antigen(s) to other reported FS antigens is presently unknown. [ABSTRACT FROM AUTHOR]

Enzyme purification and subsequent immobilization usually require multiple steps and consume plenty of chemicals. Traditional dipping incubation operation is lengthy and the interior of porous carrier is not fully exploited due to the diffusion barrier. To solve these problems, one-step enzyme purification and immobilization was developed based on membrane chromatography concept. A membrane adsorber was prepared by polydopamine coating on a PVDF microfiltration membrane (or on a cheap and disposable cellulose filter paper) and subsequent polyethyleneimine grafting, without any solvent usage. Laccase was selectively immobilized on such membrane adsorber (enzyme activity: 39.9±4.4 U/mL; expressed activity: 19.6±3.0%) by directly capturing it from a crude fermentation broth without pH adjustment under flow-through mode. The immobilized laccase had a high purity of 92.2%, while the membrane permeability decreased due to the adsorption of laccase and impurities (“membrane fouling”). Thanks to the dominant convective transport, the enzyme loading was high and much faster than that by dipping incubation (5 min vs. 80 min). Moreover, enzyme reloading on membrane adsorber was easily realized by reversible desorption-adsorption process. The constructed biocatalytic membrane exhibited a commendable reusability for bisphenol A (BPA) removal only driven by its gravity. [ABSTRACT FROM AUTHOR]

The application of phosphorus based flame retardants as replacements for commonly used halogenated flame retardants has been gaining interest due to the possibility that these compounds may have a less significant impact on human and environmental health. Unfortunately, little is known about the chemical compositions of many of the technical products (which often are mixtures) and a single separation technique for concurrent analysis of these types of compounds has not been identified. This paper reports the results of an investigation into the constituents of three halogen free organophosphate flame retardants (OPFRs), resorcinol bis(diphenyl phosphate) (RDBPP), bisphenol A bis(diphenyl phosphate) (BPA-BDPP), and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO). The major components of commercial samples of RDBPP and BPA-BDPP were isolated by preparative TLC and characterized by NMR. A commercial sample of DOPO was found to be essentially pure, but its analysis is complicated by the fact that it can exist in ring-open and ring-closed forms. With the structures of the components confirmed by NMR, multiple analytical separation techniques (gas chromatography (GC), liquid chromatography (LC), and packed column supercritical fluid chromatography (pSFC)) were investigated for the analysis of these three technical products. Packed column supercritical fluid chromatography allows the separation of the components of all three OPFRs, including the two forms of DOPO, in a single run. [ABSTRACT FROM AUTHOR]

This paper describes the use of microwave radiation in the synthesis of urethane prepolymers in bulk (without solvent). The prepolymers were synthesized using 1,6-hexamethylene diisocyanate (HDI) and poly (ε-caprolactone) diol (PCL) at a molar ratio of 4:1. The reaction was carried out without a catalyst in the reactor with a conventional heating system (oil bath) or in the microwave reactor (MW Reactor NOVA 09) at temperatures of 60, 80 and 100 °C. The progress of the reaction was monitored based on the degree of HDI and PCL conversion, as assessed by acidimetric titration of non-bonded isocyanate groups (0–120 min). The chemical structure of the resulting products was determined via Fourier Transform Infrared Spectroscopy. Size exclusion chromatography (GPC) was applied to determine the molecular weight distribution of products at different time points of prepolymer synthesis. The obtained results indicate that the use of microwave radiation as a heat source during prepolymer synthesis accelerates the reaction in the temperature range from 60 to 80 °C. This finding allows a significant reduction in energy required for heating the reaction mixture. The acceleration of prepolymer synthesis by the application of microwave radiation as a heat source also allows for the elimination of catalysts from the system. The aforementioned catalysts are necessary to perform the prepolymer synthesis with the use of aliphatic diisocyanates and polyols, particularly at temperatures below 100 °C. In the case of prepolymers that are further used in the synthesis of biomedical polyurethanes, the catalyst elimination is especially advantageous as the presence of residual catalyst may significantly influence the final material’s biocompatibility and disturb host cell viability. [ABSTRACT FROM AUTHOR]

The most common mass spectrometry approach analyzing contamination of the environment deals with targeted analysis, i.e. detection and quantification of the selected (priority) pollutants. However non-targeted analysis is becoming more often the method of choice for environmental chemists. It involves implementation of modern analytical instrumentation allowing for comprehensive detection and identification of the wide variety of compounds of the environmental interest present in the sample, such as pharmaceuticals and their metabolites, musks, nanomaterials, perfluorinated compounds, hormones, disinfection by-products, flame retardants, personal care products, and many others emerging contaminants. The paper presents the results of detection and identification of previously unreported organic compounds in snow samples collected in Moscow in March 2016. The snow analysis allows evaluation of long-term air pollution in the winter period. Gas chromatography coupled to a high resolution time-of-flight mass spectrometer has enabled us with capability to detect and identify such novel analytes as iodinated compounds, polychlorinated anisoles and even Ni-containing organic complex, which are unexpected in environmental samples. Some considerations concerning the possible sources of origin of these compounds in the environment are discussed. [ABSTRACT FROM AUTHOR]

This paper proposes a novel handheld analyzer with disposable lab-on-a-chip technology for the electrical detection of the anesthetic propofol in human plasma samples for clinical diagnoses. The developed on-chip biosensors are based on the conduction of molecularly imprinted polymers (MIPs) that employ label-free electrical detection techniques. Propofol in total intravenous anesthesia is widely used with a target-controlled infusion system. At present, the methods employed for detecting blood propofol concentrations in hospitals comprise high-performance liquid chromatography and ion mobility spectrometry. These conventional instruments are bulky, expensive, and difficult to access. In this study, we developed a novel plastic microfluidic biochip with an on-chip anesthetic biosensor that was characterized for the rapid detection of propofol concentrations. The experimental results revealed that the response time of the developed propofol biosensors was 25 s. The specific binding of an MIP to a nonimprinted polymer (NIP) reached up to 560%. Moreover, the detection limit of the biosensors was 0.1 μg/mL, with a linear detection range of 0.1–30 μg/mL. The proposed disposable microfluidic biochip with an on-chip anesthetic biosensor using MIPs exhibited excellent performance in the separation and sensing of propofol molecules in the human plasma samples. Compared with large-scale conventional instruments, the developed microfluidic biochips with on-chip MIP biosensors present the advantages of a compact size, high selectivity, low cost, rapid response, and single-step detection. [ABSTRACT FROM AUTHOR]

Membrane chromatography has significant potential for use in biopharmaceutical purification processes. However, currently available membrane chromatography devices give poor resolution and therefore their use is restricted to polishing applications, typically carried out in the flow-through mode. Laterally-fed membrane chromatography (or LFMC) was developed specifically for carrying high-resolution multi-component protein separations. Recent studies have shown that resolution obtained with LFMC is comparable to that obtained with equivalent resin-based packed bed chromatography. Therefore, LFMC combines high-resolution with high-productivity, a highly desirable attribute in any purification technique. In this paper we explain the workings of LFMC based on theoretical and experimental analysis of hydraulic flow-path and residence time distribution. Factors likely to affect efficiency of LFMC are discussed using a simple electrical circuit analogy. [ABSTRACT FROM AUTHOR]

An efficient and reproducible photopolymerized poly(ethylene glycol methacrylate methacrylate-co- allyl methacrylate) monolith was synthesized and a photografting process based on the ene-thiol click-chemistry has been performed to give anion exchange properties to the monolith. Since their introduction in the early 1990s polymethacrylate monoliths have emerged as a powerful alternative for microscale separations or sample treatment. Their relatively simple implementation in columns with small internal diameters makes them particularly attractive for the new chromatographic challenges of complex matrices analysis and on-chip separations. Despite their relatively poor ion-exchange capacity due to their highly porous structure, their use as anion exchangers is of large interest for nuclear analysis as numerous separations are based on this process. This paper presents a systematic study of the synthesis of the polymeric porous monolith and the versatile and robust functionalization method developed for the specific strong acidic media used in radiochemical procedures. The robustness of the stationary phase was tested in concentrated nitric acid. [ABSTRACT FROM AUTHOR]

Protein purification using inverse phase transition of elastin-like polypeptide (ELP) domains is a useful alternative to chromatography. Genetic fusions of ELP domains to various proteins have the ability to reversibly transition between soluble monomers and micron-sized aggregates and this has been used to selectively purify many ELP fusions. Affinity domains can enhance this technology by using specific protein binding domains to enable ELP mediated affinity capture (EMAC) of proteins of interest (POI) that have been fused to corresponding affinity ligands. In this paper, we highlight the use of Src homology 3 (SH3) domains and corresponding peptide ligands in EMAC that have differential binding affinities towards SH3 for efficient capture and elution of proteins. Furthermore, differences between capture and elution of a monomeric and a multimeric protein were also studied. [ABSTRACT FROM AUTHOR]

In this paper, the removal of NO with dual oxidant (H 2 O 2 /S 2 O 8 2− ) system was studied in a bubble column reactor. The contrast experiment for a different system showed that the combination of Na 2 S 2 O 8 and H 2 O 2 had a significant synergistic effect on NO removal. The effects of Na 2 S 2 O 8 concentration (0.02–0.2 mol/L), H 2 O 2 concentration (0.25–2 %), molar ratio of H 2 O 2 to Na 2 S 2 O 8 (0.3:0.2–0.3:0.02 mol/mol), reaction temperature (21–70 °C) and initial pH value (1–11) on the removal efficiency of NO were investigated. The NO removal efficiency increased with the increase of Na 2 S 2 O 8 and H 2 O 2 concentrations. However, above 1 % hydrogen peroxide and 0.1 mol/L persulfate, the rate of increase in NO removal efficiency gradually slowed down. The optimal molar ratio of H 2 O 2 to Na 2 S 2 O 8 is 0.3:0.1 mol/mol. The optimum temperature for the thermal activation of dual oxidant (H 2 O 2 /S 2 O 8 2- ) system was 50 °C. The highest NO removal efficiency (82 %) was obtained at pH 11. The final ionic products were analyzed by ion chromatography. Combined with N material balance, NO 3 − was the final ionic product in spent reaction solution. A preliminary reaction mechanism for the removal of NO in dual oxidant (H 2 O 2 /S 2 O 8 2− ) solution was deduced. This dual oxidant (H 2 O 2 /S 2 O 8 2 − ) system proved to be a promising reagent for wet denitration. [ABSTRACT FROM AUTHOR]

Membrane-based lateral flow immunochromatographic strip (LFICS) is widely used in various fields because of its simplicity, rapidity (detection within 10 min), and low cost. However, early designs of membrane-based LFICS for preliminary screening only provide qualitative (“yes/no” signal) or semi-quantitative results without quantitative information. These designs often suffer from low-signal intensity and poor sensitivity and are only capable of single analyte detection, not simultaneous multiple detections. The performance of existing techniques used for detection using LFICS has been considerably improved by incorporating different kinds of nanoparticles (NPs) as reporters. NPs can serve as alternative labels and improve analytical sensitivity or limit of detection of LFICS because of their unique properties, such as optical absorption, fluorescence spectra, and magnetic properties. The controlled manipulation of NPs allows simultaneous or multiple detections by using membrane-based LFICS. In this review, we discuss how colored (e.g., colloidal gold, carbon, and colloidal selenium NPs), luminescent (e.g., quantum dots, up-converting phosphor NPs, and dye-doped NPs), and magnetic NPs are integrated into membrane-based LFICS for the detection of target analytes. Gold NPs are also featured because of their wide applications. Different types and unique properties of NPs are briefly explained. This review focuses on examples of NP-based LFICS to illustrate novel concepts in various devices with potential applications as screening tools. This review also highlights the superiority of NP-based approaches over existing conventional strategies for clinical analysis, food safety, and environmental monitoring. This paper is concluded by a short section on future research trends regarding NP-based LFICS. [ABSTRACT FROM AUTHOR]

In this study, the analytical procedures for the improved extraction and determination of the selected micropollutants (anthracene, pentachlorophenol, octylphenol, benzo(a)pyrene, and diclofenac) in aqueous environment are proposed. These methods were based on application of gas chromatography coupled with mass spectrometry and solid phase extraction for isolation of tested analytes from water samples. Compared to standard procedures currently used in the range presented in this paper, the authors’ modifications of analytical procedures allowed increasing the recovery rate of analytes. Within modification of procedures, hyamine, methanol were used. The substances increase solubility of analytes in water, for instance. Toxicological potential of samples containing tested micropollutants in different environmental matrix was evaluated. Proposed analytical procedures allow the quantitative determination of five different compounds in aquatic environment with satisfactory repeatability and precision of measurements. Applied modifications of analytical procedures had an influence on the increase of recovery degree of compounds. Extraction of micropollutants from effluent exceeded 60% and depended on compounds concentration in the samples, excluding the determination for lower concentration of anthracene. The limits of quantitation LOQ (in ng/L) were as follows: 6.5 for anthracene and octylphenol, 8.5 for diclofenac, and 10 for pentachlorophenol and benzo(a)pyrene. It was found that Microtox®assay allows the quick evaluation of toxicological potential of selected micropollutants. The toxicological potential (expressed as EC50, in mg/L) of deionized water samples containing micropollutants was equal to: 12.8; 2.2; 1.4; 6.6; 23.1 for anthracene, pentachlorophenol, octylphenol, benzo(a)pyrene, and diclofenac, respectively. However, the toxicity was also dependent on environmental matrix. The explanation of this phenomenon requires further research. [ABSTRACT FROM PUBLISHER]

Due to their proven performance and improved availability, core–shell particles are increasingly applied for chromatographic separations. This paper presents semi-analytical solutions and a moment analysis of a detailed mathematical model for fixed-beds packed with core–shell particles. The model considers axial dispersion, interfacial mass transfer, intraparticle diffusion, linear adsorption, and the injection of rectangular pulses. The Laplace transformation is used as a basic tool to derive semi-analytical solutions. In addition the first three statistical temporal moments are derived from solutions in the Laplace domain. The numerical Laplace inversion is applied for back transformation of the solution in the actual time domain. In order to demonstrate their potential, different scenarios are considered to quantify the effects of the relative core size, axial dispersion, film mass transfer resistance and intraparticle diffusion resistance in the porous layer on the elution profiles. An important new result is the derivation of a plate height equation for fully porous and core–shell particles respecting the Danckwerts boundary conditions. [ABSTRACT FROM AUTHOR]

Butyl-acrylate (BA) containing branched poly-(N-isopropyl acrylamide) or PNIPAM copolymer was grafted on filter paper to prepare composite membrane for carrying out temperature-responsive hydrophobic interaction membrane chromatography (HIMC) of proteins. The copolymer demonstrated two-step phase transition behavior due to the presence of BA and PNIPAM, making the changeover from hydrophilic to hydrophobic state more tunable. The feasibility of using the temperature-responsive membrane was demonstrated by controlling human immunoglobulin G (hIgG) binding and release using temperature change. Higher temperature promoted protein binding and lower temperature favored protein release in this process, which was carried out using lyotropic salt-free mobile phase. The purification of monoclonal antibody (mAb) hIgG1-CD4 from simulated CHO cell culture supernatant was carried out to demonstrate practical application for the novel temperature-responsive membrane. [ABSTRACT FROM AUTHOR]