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Potent muscle relaxant (thiocolchicoside, TCC) and nonsteroidal anti-inflammatory drug (etoricoxib, ETXB) fixed-dose combination is formulated at relatively high 1:15 and 1:7.5 ratios for TCC and ETXB, respectively. Since the minor component (TCC) has lower absorptivity, assay of TCC/ETXB tablets presents an analytical challenge. The current study presents two novel methods: first is a micellar electrokinetic capillary chromatography (MEKC). Background electrolyte is borate buffer (40 mM, pH 9.2) containing 30 mM sodium dodecyl sulfate and methanol (ratio 80:20%, v/v), measured at 210 nm. Second is a direct double A max spectrophotometric method; minor component, TCC, is measured directly at its distant λ max (373 nm), at zero absorption of ETXB. Then, a ten-fold dilution step is carried out to eliminate TCC spectral interference and ETXB is determined at its λ max (282 nm). Both drugs’ concentrations disclose obedient linearities at 2–100 μg·mL−1 in MEKC, versus 3–25 and 40–350 μg·mL−1 for TCC and ETXB, respectively, in spectrophotometry. All ICH validation elements have been fulfilled for the developed methods. MEKC and spectrophotometric assays achieve accuracy, precision, selectivity, and robustness to be recommended for industrial quality control routine analysis of TCC/ETXB pills formulated at cited ratios or even higher.

Ethanol extracts of three widely growing plants were added to silica sol–gel solutions, which were subsequently applied as wall surface modifiers in inner quartz capillaries. Modified capillaries were used for open-tubular capillary electrochromatographic separation of nucleotides and amino groups containing biological compounds (neurotransmitters, amino acids and oligopeptides). The experiments were performed at physiological pH 7.40, and eventual changes of effective mobilities were calculated. Specific compounds characteristic for each plant were tested as sol–gel additives as well, and thus-modified capillaries were used for the separations of the same analytes under identical conditions. The aim of this study was to find out possible interactions between physiological compounds and extracts of freely available plants anchorded in the sol-gel stationary phase in the flowing system. Even though the amount of the modifier in each capillary is very small, basic statistical evaluation showed some not negligible changes in effective mobility of tested analytes. These changes were bigger than ±5% for separations of nucleotides in capillaries with curcuma, Moringa or the mixture of synthetic additives as the sol-gel aditive, and for separations of amino compounds where these changes varying by additive, analyte by analyte. [ABSTRACT FROM AUTHOR]

Ethanol extracts of three widely growing plants were added to silica sol–gel solutions, which were subsequently applied as wall surface modifiers in inner quartz capillaries. Modified capillaries were used for open-tubular capillary electrochromatographic separation of nucleotides and amino groups containing biological compounds (neurotransmitters, amino acids and oligopeptides). The experiments were performed at physiological pH 7.40, and eventual changes of effective mobilities were calculated. Specific compounds characteristic for each plant were tested as sol–gel additives as well, and thus-modified capillaries were used for the separations of the same analytes under identical conditions. The aim of this study was to find out possible interactions between physiological compounds and extracts of freely available plants anchorded in the sol-gel stationary phase in the flowing system. Even though the amount of the modifier in each capillary is very small, basic statistical evaluation showed some not negligible changes in effective mobility of tested analytes. These changes were bigger than ±5% for separations of nucleotides in capillaries with curcuma, Moringa or the mixture of synthetic additives as the sol-gel aditive, and for separations of amino compounds where these changes varying by additive, analyte by analyte.

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Background: The objective of this study was to determine the features of fragment length for circulating cell-free DNA (cfDNA) from plasma and serum samples. Methods: Plasma and serum samples from different sources were randomly collected. Circulating cfDNA was extracted and purified by a precipitation-enriched and spin-column-based kit. The concentration of the purified DNA was immediately measured by a highly sensitive dsDNA quantitative assay, and then the fragment length was analyzed by capillary electrophoresis. The abundance of a specific fragment was estimated by the area under curve (AUC) for the fragment peak in the capillary electrophoresis. Results: A total of 199 plasma and 117 serum samples were extracted and analyzed. The average yield of cfDNA from the serum samples (131.67 ng/mL) was significantly higher than that from the plasma samples (32.78 ng/mL, p < 0.001). The average abundance of the 20–400 bp fragments in plasma cfDNA (84.4%) was significantly higher than that of serum cfDNA (51.9%, p < 0.001). Fragment peaks in serum cfDNA always presented in regions around 190 bp, 430 bp, and 630 bp, but plasma cfDNA generally showed a sharp peak in the 165–190 bp region and a much lower peak in the 300

Metal-organic cages (MOCs) are a novel kind of porous materials which have three dimensional structures with perpetual and well-defined holes. They have attracted wide consideration for relatively simple synthesis and potential applications such as separation, sensing, microreactor and catalysis etc. In this study, a homochiral MOC [Zn 3 L 2 ] was prepared as a novel stereoselective stationary phase and added into poly (ionic liquid- co -ethylene dimethacrylate) (Zn 3 L 2 @poly(IL- co -EDMA)) monolith for capillary electrochromatography (CEC). The chiral analytes comprising mandelic acid, benzoin and furoin enantiomer were separated perfectly using the monolithic column Zn 3 L 2 @poly(IL- co -EDMA), and the effects of buffer pH, acetonitrile percentage and buffer concentration on enantiomers separation were confirmed. Moreover, incorporation of MOC [Zn 3 L 2 ] into IL polymer monolith strengthened obviously the stereoselective isolation of some positional isomers (such as nitrophenols, nitrotoluenes, xylenes, and ionones). The relative standard deviations (RSDs) of the retention time for intra-day (n = 5) and inter-day (n = 3) and column-to-column (n = 3) enantioseparations were all below 5.0%. This novel monolithic column combined distinct features of the stereoselective materials with the eminent traits of ionic liquid matrix, it has great application potential in CEC. Image 1 • Homochiral MOC [Zn 3 L 2 ] was first used as novel stationary phases for CEC. • The Zn 3 L 2 @poly(IL- co -EDMA) monolith was successfully prepared by one-step copolymerization. • The monolithic column showed good separation selectivity for isomers and enantiomers. • The Zn 3 L 2 @poly(IL- co -EDMA) monoliths exhibited excellent reproducibility and stability. [ABSTRACT FROM AUTHOR]

This review critically discusses the developments on open-tubular liquid chromatography (OT-LC) and open-tubular capillary electrochromatography (OT-CEC) during 2014–2018. An appropriate Scopus search revealed 5 reviews, 4 theoretical papers on open-tubular format chromatography, 29 OT-LC articles, 68 OT-CEC articles and 4 OT-LC/OT-CEC articles, indicating a sustained interest in these areas. The open-tubular format typically uses a capillary column with inner walls that are coated with an ample layer or coating of solid stationary phase material. The ratio between the capillary internal diameter and coating thickness (CID/CT) is ideally ≤ 100 for appropriate chromatographic retention. We, therefore, approximated the CID/CT ratios and found that 22 OT-LC papers have CID/CT ratios ≤100. The other 7 OT-LC papers have CID/CT ratio >100 but have clearly demonstrated chromatographic retention. These 29 papers utilised reversed phase or ion exchange mechanisms using known or innovative solid stationary phase materials (e.g. metal organic frameworks), stationary pseudophases from ionic surfactants or porous supports. On the other hand, we found that 68 OT-CEC papers, 7 OT-LC papers and 4 OT-LC & OT-CEC papers have CID/CT ratios >100. Notably, 44 papers (42 OT-CEC and 2 OT-LC & OT-CEC) did not report the retention factor and/or effective electrophoretic mobility of analytes. Considering all covered papers, the most popular activity was on the development of new chromatographic materials as coatings. However, we encourage OT-CEC researchers to not only characterise changes in the electroosmotic flow but also verify the interaction of the analytes with the coating. In addition, the articles reported were largely driven by stationary phase or support development and not by practical applications. Image 1 • Developments in OT-LC and OT-CEC during 2014–2018 were critically reviewed. • Appropriate coating thickness inside narrow capillaries were implemented in OT-LC. • Lack of rigour in reporting the chromatographic effect of coatings in OT-CEC. • OT-LC and OT-CEC are still in the exploratory or research phase. • Focus was on development of innovative stationary phase materials and supports. [ABSTRACT FROM AUTHOR]

Surfactant bilayers or admicelles at the solid surface-liquid interface inside 50–200 μm inner diameter (i.d.) open-tube fused-silica capillaries were developed as 'soft' stationary pseudophases for the liquid chromatographic (LC) separations of neutral and charged analytes. Admicelles were formed in-situ from buffered aqueous mobile phases with cetytrimethylammonium bromide at concentrations between the critical surface aggregation concentration and critical micelle concentration, which were determined by electroosmotic flow measurements using capillary electrophoresis. There were no micelles in the mobile phase solution. Also, there was no solid phase that is classically required in LC. Pressure and voltage driven modes or open-tubular admicellar liquid chromatography (OT-AMLC) and electrochromatography, respectively were proposed based on the separation of neutral analytes. The parameters (i.e., pH, concentration of surfactant, salt, and methanol in the mobile phase and capillary i.d.) that affected the surprising chromatographic effect of admicelles at the interface were investigated. The analytical performance of OT-AMLC for small molecules were found acceptable. Applications to environmental water and biological (HepG cell line metabolism media) samples analysis with appropriate sample preparation procedures were also conducted. The use of pseudophases at the solid surface-liquid interface could be a viable solution to problems associated with the use of solid stationary or support materials in nano- and micro-liquid chromatography and electrochromatography. Image 1 • Open-tubular chromatography and electrochromatography without a solid stationary phase or support. • CTAB admicelles at the inner fused silica capillary surface-liquid interface. • Admicelles as stationary pseudophase in chromatography and electrochromatography. • Separation of neutral and charged analytes. • Potential for applications to environmental and biological sample analysis. [ABSTRACT FROM AUTHOR]

• Multi-particles serve as frits for packed columns based on keystone effect. • Multi-particle frits are short, permeable and of easy preparation. • Multi-particle fritting is feasible for CEC columns of various inter diameters. • Good over-run and over-column reproducibilities were obtained. Further development of capillary electrochromatography (CEC) is to some extent restricted by column technology. Packed capillary columns are most commonly used in CEC because of higher sample capacity and higher sensitivity than open tubular columns, and better reproducibility and uniformity than monolithic columns. Fritting is the core component for the fabrication of packed capillary columns. Therefore various fritting technologies attract continuous attention from analytical community. A convenient fritting method was developed in this study. In contrast to the reported single-particle fritting, this method applies a multi-particle fritting technology to hold stationary phase in capillary columns. Several large porous particles smaller than the column internal diameter were tapped in and immobilized in inlet and outlet of the packing material bed due to direct and indirect keystone effect. Except the smallest permeability by the sintered frit and the lowest breaking pressure by the single-particle frit, EOF mobility and peak dispersion of the multi-particle frit were at the same levels with the formers. In addition, all the three frits avoided bubble formation. It demonstrated that the multi-particle frits met the general requirements of permeability, mechanical resistance and efficiency for packing capillary microcolumns as well as the sintered frits and the single-particle frits. Thus, peak efficiency around 4.3 μm plate height (approximately 232,560 plates per meter) was obtained by multi-particle fritted capillary columns with electrokinetic packing, compared to 6.5 μm plate height by single-particle fritted columns with slurry pressure packing. In particular, the multi-particle fritting was simpler, faster, and more reproducible than the sintered fritting, and the multi-particle fritting was suitable to pack capillary columns of various capillary bore sizes owing to rich commercial resources of fritting particles of various diameters. Multi-particle fritted columns offered satisfactory run-to-run and column-to-column reproducibilities for retention factor, plate height and peak area (precisions of 4.1–9.3% for 10 replicated columns, and precisions of 0.9–3.1% for 30 replicated trials). They also had consistent CEC performance (differences of 1.1–3.9% between the first and 31 st day) during a lifetime more than one month. Application examples in packing capillary columns of 75 and 100 μm i.d. and CEC analysis of sixteen polycyclic aromatic hydrocarbons prove the diversity and reliability of the multi-particle fritting in column technology. [ABSTRACT FROM AUTHOR]

Concepts leading to single enantiomers of chiral molecules are of crucial importance for many applications, including pharmacology and biotechnology. Recently, mesoporous metal phases encoded with chiral information have been developed. Fine‐tuning of the enantioaffinity of such structures by imposing an electric potential is proposed, which can influence the electrostatic interactions between the chiral metal and the target enantiomer. This allows the binding affinity between the chiral metal and the target enantiomer to be increased, and thus, the discrimination between two enantiomers to be improved. The concept is illustrated by generating chiral encoded metals in a microfluidic channel by reduction of a platinum salt in the presence of a liquid crystal and l‐tryptophan as a chiral model template. After removal of the template molecules, the modified microchannel retains a pronounced chiral character. The chiral recognition efficiency of the microchannel can be fine‐tuned by applying a suitable potential to the metal phase. This enables the separation of both components of a racemate flowing through the channel. The approach constitutes a promising and complementary strategy in the frame of chiral discrimination technologies. In for a shock: The electric potential of a mesoporous chiral platinum phase can be tuned to allow quantitative separation of the enantiomers in a tryptophan racemate. An applied potential influences the electrostatic interactions, and thereby the enantioaffinity, between the chiral metal and the target enantiomer. [ABSTRACT FROM AUTHOR]

Core-shell particle is a new generation high performance packing material for liquid chromatography. Through comparison with a classical totally porous silica phase of the same particle size, we studied Ascentis Express 5 μm core-shell particle's electrochromatographic behavior, in terms of voltage-current property, electroosmotic flow (EOF) and van Deemter curve. It was found, due to the nonpermeable solid core, the core-shell particle presented a diminished EOF and efficiency than the totally porous paricle. This on the other hand proved that the intra-particle pore flow extensively exists and plays an important role in electrochromatography on totally porous material. The core-shell particle's high retentivity led to an enhanced resolution for weakly retained hydrophilic peptides, which were poorly retained and co-eluted on totally porous particles. Further exploration has shown the core-shell material can achieve efficient electrochromatography of protein digests, excellent performance in terms of resolution, reproducibility and long term stability have been observed. The results indicate that the core-shell structure may suggest a reasonable design of stationary phase for bioelectrochromatography of peptides and proteins. [ABSTRACT FROM AUTHOR]

A carbamoylated clarithromycin‐incorporated zirconia hybrid monolith (CLA‐ZHM) was prepared in a fused silica capillary via an in situ sol–gel process. The CLA‐ZHM capillary column was employed for enantiomer separation of acidic chiral compounds by capillary electrochromatography in eluents consisting of acetonitrile, methanol, and acetic acid and triethylamine as electrolytes. Influences of the composition of eluent and applied voltage on enantiomer separation were investigated. Baseline resolutions were achieved for 10 acidic compounds in an eluent consisting of 70/30 acetonitrile/methanol with 255 mM acetic acid and 17.4 mM triethylamine at an applied voltage of −10 kV and capillary temperature of 25 °C. Relative standard deviation values in resolution parameters for column to column and batch to batch repeatability were less than 2.7% (for n = 3) under the optimal separation settings, indicating that stability of the ZHM columns and reproducibility of the column preparation method are acceptable. [ABSTRACT FROM AUTHOR]

Bacteria, the microorganism with intrinsic chirality, have numerous fascinating chiral phenomena such as various chirality-triggered biological processes and behaviors. Herein, bacteria were firstly explored as novel chiral stationary phases in open-tubular capillary electrochromatography (OT-CEC) for enantioseparation of fluoroquinolone enantiomers and simultaneous separation of six fluoroquinolone antibiotics. The model strain, i.e. non-pathogenic Escherichia coli ( E. coli ) DH5α, was adhered onto the inner surface of positively charged polyethyleneimine (PEI) modified capillaries based on the bacterial adhesion characteristics and strong electrostatic interaction. The morphology and thickness of the bacteria adhesive coatings in the capillary were characterized by field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). Baseline separation of ofloxacin and partial separation of lomefloxacin enantiomers could be achieved by the E. coli coated columns. The preparation parameters including the coating time and concentration of bacteria that affecting the chiral resolution were intensively investigated. The electrophoretic parameters, including pH, buffer concentration and applied voltage, were also optimized. The developed method was validated (linearity, LOD, LOQ, intra-day, inter-day and column-to-column repeatability and recovery) and successfully utilized for the quantitative analysis of ofloxacin enantiomers in the ofloxacin tablets. Moreover, only a slight decrease in the separation efficiency was observed after 90 consecutive runs on the E. coli @capillary. These results demonstrated that bacteria are promising stationary phases for chiral separation in CEC. [ABSTRACT FROM AUTHOR]

The orthogonal pressurized planar electrochromatography (OPPEC) is an example of 2-D separation technique, in which two simultaneous and orthogonal processes of electrophoresis and chromatography are involved in the separation mechanism. In the case of preparative separation of substances characterized by different electrophoretic mobility, such separation system can be constantly fed with the sample solution and the separated components can be constantly collected at its outlet. In the paper, as opposed to the previous studies, we discuss the capabilities of OPPEC technique for preparative separation of substances characterized by the same electrophoretic mobility. According to the proposed solution, the separation system can be periodically fed with the sample solution and separated components can be collected alternately at its outlet. The advantages of this new approach over the column chromatography with regard to the separation of complex mixtures have been signaled. [ABSTRACT FROM AUTHOR]

Carboxylated single-walled carbon nanotubes (c-SWNTs) were incorporated into poly(glycidylmethacrylate-co-ethylene glycol dimethacrylate) [poly(GMA-co-EDMA)] monoliths to develop a novel monolithic stationary phase for capillary electrochromatography. The prepared monoliths were characterized by scanning electron microscopy and nitrogen adsorption. Additionally, pepsin, which is a chiral selector, was bonded to the c-SWNT-incorporated monoliths via epoxide groups as reactive sites and glutaraldehyde as the spacer. The effects of the c-SWNT concentration on chiral separation were investigated, and the results suggested that the c-SWNTs played a significant role in improving the separation efficiency, although pepsin was the dominant element in determining the chiral recognition ability of the monolith. Moreover, the influences of buffer pH, operating voltage and sample volume were also studied with (±)-nefopam as a model drug. Under the optimized conditions, the pepsin-modified poly(GMA-c-SWNTs-EDMA) monolith exhibited excellent enantioseparation performance for ten pairs of basic chiral drugs and extended the scope of chiral separation of drug enantiomers. [ABSTRACT FROM AUTHOR]

A refractive index sensor has been fabricated in silicon oxynitride by standard UV lithography and dry etching processes. The refractive index sensor consists of a 1D photonic crystal (PhC) embedded in a microfluidic channel addressed by fiber-terminated planar waveguides. Experimental demonstrations performed with several ethanol solutions ranging from a purity of 96.00% (n = 1.36356) to 95.04% (n = 1.36377) yielded a sensitivity (Δλ/Δn) of 836 nm/RIU and a limit of detection (LOD) of 6 x 10-5 RIU, which is, however, still one order of magnitude higher than the theoretical lower limit of the limit of detection 1.3 x 10–6 RIU.

Fabricating metal-organic frameworks (MOFs) with the use of nucleating agents in the microenvironment have attracted increasing attention recently. Herein, a simple and rapid synthesis method was developed to in situ fabricate homochiral MOF [Zn(s-nip)2]n in the capillary inner wall by using ZnO nanoparticles as efficient nucleating agents for open tubular capillary electrochromatography (OT-CEC) separation of monoamine neurotransmitters enantiomers of epinephrine, isoprenaline and synephrine, the diastereoisomers of ephedrine and pseudoephedrine, the isomers of nitrophenols and analogues of bisphenols with good resolution. The relative standard deviations (RSDs) for the analytes migration time of intra-day, inter-day and column-to-column were in the range of 0.8-2.1% (n = 10), 0.3-3.2% (n = 3) and 3.2-9.3% (n = 3), respectively. Additionally, the homochiral MOF [Zn(s-nip)2]n coated capillary column could be successively used over 260 runs without observable change in the separation efficiency. [ABSTRACT FROM AUTHOR]

Orthogonal pressurized planar electrochromatography (OPPEC) is the new separation technique, in which two simultaneous and orthogonal processes of electrochromatography/electrophoresis and chromatography proceed under external pressure. It means in the OPPEC separation system a mobile phase solution hydrodynamically flows against adsorbent layer of the chromatographic plate and electric field is orthogonally applied to it. This technique can be applied to analytical and preparative separations. In the paper we report influence of some operating variables on continuous preparative OPPEC separation of test dyes in system with HPTLC RP-18W plates from Merck and methanol–buffer mobile phase. The following operation variables are discussed: external pressure exerted on the adsorbent layer, mobile phase flow velocity, and the ratio of flow velocities of the mobile phase to the sample solution, voltage applied to electrodes, modifier concentration in the mobile phase, concentration and pH of buffer. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants which can reach the environment and food in different ways. Because of their high toxicity, two international regulatory institutions, the US Environmental Protection Agency and the European Food Safety Authority, have classified PAHs as priority pollutants, generating an important demand for the detection and identification of PAHs. Thus, sensitive, fast, and cheap methods for the analysis of PAHs in environmental and food samples are urgently needed. Within this context, electrophoresis, in capillary or microchip format, displays attractive features. This review presents and critically discusses the published literature on the different approaches to capillary and microchip electrophoresis analysis of PAHs. [ABSTRACT FROM AUTHOR]

This review covers various approaches now available to enhance the surface area of stationary phases fabricated in the porous layer open tubular (PLOT) format for use in liquid-phase-based separation techniques and catalytic applications. We focus attention on the preparation of porous polymers (monoliths), since many procedures have already been described related to the production of PLOT columns with distinctive properties and coatings at the column wall. We discuss advantages and limitations of these methodologies with regard to materials used and the demonstrated application. [ABSTRACT FROM AUTHOR]

Tocotrienols, members of the vitamin E family, are natural compounds found in a number of vegetable oils, wheat germ, barley and certain types of nuts and grains. Vegetable oils provide the best sources of these vitamin E forms, particularly palm oil and rice bran oil contain higher amounts of tocotrienols. Other sources of tocotrienols include grape fruit seed oil, oats, hazelnuts, maize, olive oil, buckthorn berry, rye, flax seed oil, poppy seed oil and sunflower oil. Tocotrienols are of four types, viz. alpha (α), beta (β), gamma (γ) and delta (δ). Unlike tocopherols, tocotrienols are unsaturated and possess an isoprenoid side chain. A number of researchers have developed methods for the extraction, analysis, identification and quantification of different types of vitamin E compounds. This article constitutes an in-depth review of the chemistry and extraction of the unsaturated vitamin E derivatives, tocotrienols, from various sources using different methods. This review article lists the different techniques that are used in the characterization and purification of tocotrienols such as soxhlet and solid-liquid extractions, saponification method, chromatography (thin layer, column chromatography, gas chromatography, supercritical fluid, high performance), capillary electrochromatography and mass spectrometry. Some of the methods described were able to identify one form or type while others could analyse all the analogues of tocotrienol molecules. Hence, this article will be helpful in understanding the various methods used in the characterization of this lesser known vitamin E variant. [ABSTRACT FROM AUTHOR]

This manuscript is intended to summarize strategies developed to chemically functionalize the surface of porous polymeric materials using the so-called click reactions with the general aim of developing chromatographic stationary phases with well-defined interfacial characteristics. The preparation pathway starts with the synthesis of polymeric materials with micrometre-sized channel-like pores providing enhanced permeability and fast mass transfer. Such monolithic structure is obtained by solvent-induced phase separation occurring in the course of the free radical polymerization of functional monomers and crosslinkers mixture. The presence of functional groups on the monolith surface allows its further functionalization through click chemistry. Herein, implementation of Huisgen, thiol-ene, thiol-yne and diels--alder click-type reactions is discussed for the grafting of molecular and oligomeric selectors. This work undoubtedly highlights click-surface chemistry as a powerful surface modification strategy for tuning, at the molecular level, the chemical nature of pores surface. [ABSTRACT FROM AUTHOR]

Duplex capillary columns, the standard for electrochromatography using optical detection, consist of a packed and an open section. Normally, optical detection is performed in an on-column manner, i.e. at a point right after the packed section. It was deemed that band broadening may take place when an analyte band travels from the packed bed, through the frit and down to the open section. In this study, without using any sintering steps for fritting or window creation, robust packed capillary columns were prepared using transparent capillaries based on single particle fritting technology. The detection point could be easily shifted by simply sliding the transparent column against the ultraviolet (UV) beam. In this way, the band broadening effect was directly evaluated as a function of the detection point, which was positioned before or after the end frit. The consistent van Deemter curves recorded indicate that there was no efficiency difference between the positions investigated. The result proved that the significant band broadening effect previously observed via on-column detection should be caused by the sintered frit used, while the single particle frit made through a purely physical process did not lead to efficiency degradation. The conservative separation performance recorded at different positions around the column's end also suggests the applicability of on-line tandem detection strategy, e.g. UV followed by mass spectrometry (MS), on the same capillary column, which should be a promising approach to mining multiplex detection information from a single microseparation process. [ABSTRACT FROM AUTHOR]

A novel chiral stationary phase consisting of an amidopropyltrimethylammonium chloride divinylbenzene (APAT-DVB) polymer containing the chiral selector heptakis(2,3-di-O-acetyl-6-O-sulfo)-β-cyclodextrin (HSβCD) has been employed in porous layer open tubular (PLOT) capillary column format with various conditions evaluated to optimize the polymerization and chiral selector immobilization. Scanning electron microscopy demonstrated a near homogenous longitudinal open path in the column with a polymer film of uniform thickness. IR spectroscopy characterized the functional groups of the polymer and energy-dispersive X-ray spectroscopy provided further evidence of the successful polymer modification with HSβCD. Optimum electrochromatographic separation conditions were elaborated with respect to organic solvent content and pH of the background electrolyte. Colum-to-column and long-term reproducibility was excellent. The effectiveness of the new capillary column was demonstrated with the successful separation of d-and l-aspartic acid, d- and l-tyrosine and d-and l-lysine. [ABSTRACT FROM AUTHOR]

Highlights: [•] Simplex column configuration with an essentially fully packed bed was introduced. [•] Single particle fritting technology enabled fabrication of robust simplex columns. [•] Simplex column has uniform electric field distribution and higher efficiency. [•] Simplex column configuration should enable regulation of electroseparation speed. [•] Bidirectional electrochromatography was demonstrated using a simplex column. [Copyright &y& Elsevier]

Highlights: [•] We propose and optimize a new procedure to form silica end frits in capillary columns. [•] The method is based on thermal sintering of particles using axial transfer of heat. [•] The method is robust, reproducible and save the polyimide coatings. [•] The obtained frits are short, permeable, resistant, efficient and do not form bubbles. [ABSTRACT FROM AUTHOR]

Highlights: [•] Overpressured layer chromatography (OPLC). [•] Pressurized planar electrochromatography (PPEC). [•] Two dimensional orthogonal combination of OPLC and PPEC into simultaneous process. [•] Orthogonal pressurized planar electrochromatography (OPPEC). [•] Application of OPPEC to preliminary analytical and micro-preparative separations. [Copyright &y& Elsevier]

Highlights: [•] Monolithic phases are prepared with different hydrophobic and fluorous fraction. [•] Phase selectivity is probed using different fluorous and hydrophobic analytes. [•] The strength of different fluorous interactions is determined with CEC migration data. [•] Hypothetical water percentage describes monolithic fluorous/hydrophobic character. [ABSTRACT FROM AUTHOR]

This work describes novel devices for electric field-assisted solid phase extraction (E-SPE) and an application was carried out on the antimicrobial marbofloxacin (MAR). Conventional syringe-type SPE cartridges were easily adapted to receive two electrodes that were inserted and positioned below and above the sorbent. The adapted cartridges were coupled to a flow extraction system, which consisted of an electrophoresis power supply, a peristaltic pump and a homemade SPE manifold. These devices were used to apply electric fields during the extraction of MAR from fortified buffer and milk samples. The recovery of MAR was improved (2.3 times) or reduced (4.2 times) in comparison to conventional SPE when the top electrode was used as cathode (E-SPE) or anode (E-SPE), respectively. The results demonstrated that usual SPE cartridges can be easily and inexpensively adapted for applying an electric field in SPE. It was also concluded that the electric field applied in a usual SPE cartridge can be employed as a new suitable approach to enhance the extraction efficiency of ionic compounds in a complex sample matrix. [ABSTRACT FROM AUTHOR]