Core-shell Technology Research Articles

The use of core-shell high-performance liquid chromatography column technology to improve biogenic amine quantification in wine.

HPLC column technology has been improved, providing better resolution of closely eluting compounds, better analyte sensitivity, and shorter analysis times. The core-shell technology columns offer a faster analysis through the use of shorter columns without compromising resolution. The aim of this work was to improve the methods for determination of biogenic amines (BAs) in wine using the new HPLC PFP core-shell column technology. Two different elution programs were designed to quantify BAs with the core-shell PFP column. Program I flow rate was 2 mL min(-1). The total elution time was 10 min. In elution program II, the flow rate was 0.8 mL min(-1) and the total elution time was 25 min. The two elution programs used with the core-shell PFP HPLC column showed differences related mainly to the histamine peak. The chromatograms showed that when a temporary isocratic elution was added in the gradient (program II), the histamine peak was eluted later, causing its isolation, and therefore its quantification was easier. Compared to the previous C18 HPLC column for the BAs determination in wine, the main advantage of the presented technique is the reduction of the run times and solvent volumes, and has a better sensitivity and selectivity as peaks are higher and sharper.

Prediction of HPLC retention times of tebipenem pivoxyl and its degradation products in solid state by applying adaptive artificial neural network with recursive features elimination

A sensitive and fast HPLC method using ultraviolet diode-array detector (DAD)/electrospray ionization tandem mass spectrometry (Q-TOF-MS/MS) was developed for the determination of tebipenem pivoxyl and in the presence of degradation products formed during thermolysis. The chromatographic separations were performed on stationary phases produced in core–shell technology with particle diameter of 5.0µm. The mobile phases consisted of formic acid (0.1%) and acetonitrile at different ratios. The flow rate was 0.8mL/min while the wavelength was set at 331nm. The stability characteristics of tebipenem pivoxyl were studied by performing stress tests in the solid state in dry air (RH=0%) and at an increased relative air humidity (RH=90%). The validation parameters such as selectivity, accuracy, precision and sensitivity were found to be satisfying. The satisfied selectivity and precision of determination were obtained for the separation of tebipenem pivoxyl from its degradation products using a stationary phase with 5.0µm particles. The evaluation of the chemical structure of the 9 degradation products of tebipenem pivoxyl was conducted following separation based on the stationary phase with a 5.0µm particle size by applying a Q-TOF-MS/MS detector. The main degradation products of tebipenem pivoxyl were identified: a product resulting from the condensation of the substituents of 1-(4,5-dihydro-1,3-thiazol-2-yl)-3-azetidinyl]sulfanyl and acid and ester forms of tebipenem with an open β-lactam ring in dry air at an increased temperature (RH=0%, T=393K) as well as acid and ester forms of tebipenem with an open β-lactam ring at an increased relative air humidity and an elevated temperature (RH=90%, T=333K). Retention times of tebipenem pivoxyl and its degradation products were used as training data set for predictive model of quantitative structure–retention relationship. An artificial neural network with adaptation protocol and extensive feature selection process was created. Input parameters for model were calculated from molecular geometries optimized with application of Density Functional Theory. The model was prepared and optimized especially for small data sets such as degradation products of specific compound. Validation of the model with statistical test against requirements for QSAR showed its ability for prediction of retention times within given data set. Mean error of 24.75% (0.8min) was achieved with utilization of topological, geometrical and electronic descriptors.

A Novel Stability Indicating HPLC Assay Method for Simultaneous Estimation of Clopidogrel and Aspirin in Tablet dosage form by Using Core shell Technology column

A novel, rapid and a stability-indicating reverse phase LC method has been developed and validated for the simultaneous estimation of Clopidogrel and Aspirin in tablet dosage form. The chromatographic separation was achieved on a novel core shell technology phenyl hexyl stationary phase of particle size 2.6μ. The method employed a linear gradient elution and the detection wavelength was set at 220nm. The proposed method was extensively validated as per ICH guidelines. The specificity of the method was proved by performing forced degradation studies. Regression analysis shows r value (correlation coefficient) of greater than 0.999 for individual active drug substances. Accuracy was proved in the range of 50% to 150% of working range.

Transfer of pharmacopoeial liquid chromatography reversedphase methods for determination of related compounds in diclofenac sodium and metamizole sodium from conventional to core-shell column

Core-shell silica particles were developed as a new material for chromatographic stationary phases in order to provide fast and high efficiency separations of small and large molecules and complex samples, at pressures compatible with conventional HPLC equipment. The aim of our work was to show the applicability of the HPLC columns based on a core-shell technology for determination of related substances in diclofenac sodium and in metamizole sodium using the methods described in the corresponding monographs of the European pharmacopoeia. The obtained results have shown that the proposed methods can be successfully transferred on core shell column, with suitable adjustment of injection volume and flow rate. The advantage of using core-shell column is fast and highly efficient separation on conventional HPLC equipment with increased sensitivity of the method and high throughput of the analysis, providing enhanced lab productivity and reduced costs.

Systematic evaluation of commercially available ultra-high performance liquid chromatography columns for drug metabolite profiling: Optimization of chromatographic peak capacity

The present study investigated the practical use of modern ultra-high performance liquid chromatography (UHPLC) separation techniques for drug metabolite profiling, aiming to develop a widely applicable, high-throughput, easy-to-use chromatographic method, with a high chromatographic resolution to accommodate simultaneous qualitative and quantitative analysis of small-molecule drugs and metabolites in biological matrices. To this end, first the UHPLC system volume and variance were evaluated. Then, a mixture of 17 drugs and various metabolites (molecular mass of 151–749Da, logP of −1.04 to 6.7), was injected on six sub-2μm particle columns. Five newest generation core shell technology columns were compared and tested against one column packed with porous particles. Two aqueous (pH 2.7 and 6.8) and two organic mobile phases were evaluated, first with the same flow and temperature and subsequently at each column's individual limit of temperature and pressure. The results demonstrated that pre-column dead volume had negligible influence on the peak capacity and shape. In contrast, a decrease in post-column volume of 57% resulted in a substantial (47%) increase in median peak capacity and significantly improved peak shape. When the various combinations of stationary and mobile phases were used at the same flow rate (0.5mL/min) and temperature (45°C), limited differences were observed between the median peak capacities, with a maximum of 26%. At higher flow though (up to 0.9mL/min), a maximum difference of almost 40% in median peak capacity was found between columns. The finally selected combination of solid-core particle column and mobile phase composition was chosen for its selectivity, peak capacity, wide applicability and peak shape. The developed method was applied to rat hepatocyte samples incubated with the drug buspirone and demonstrated to provide a similar chromatographic resolution, but a 6 times higher signal-to-noise ratio than a more traditional UHPLC metabolite profiling method using a fully porous particle packed column, within one third of the analysis time. In conclusion, a widely applicable, selective and fast chromatographic method was developed that can be applied to perform drug metabolite profiling in the timeframe of a quantitative analysis. It is envisioned that this method will in future be used for simultaneous qualitative and quantitative analysis and can therefore be considered a first important step in the Quan/Qual workflow.

Comparison of core–shell and totally porous ultra high performance liquid chromatographic stationary phases based on their selectivity towards alfuzosin compounds

This paper focuses on the application of a column classification system based on the Katholieke Universiteit Leuven for the characterization of physicochemical properties of core–shell and ultra-high performance liquid chromatographic stationary phases, followed by the verification of the reliability of the obtained column classification in pharmaceutical practice. In the study, 7 stationary phases produced in core–shell technology and 18 ultra-high performance liquid chromatographic columns were chromatographically tested, and ranking lists were built on the FKUL-values calculated against two selected reference columns. In the column performance test, an analysis of alfuzosin in the presence of related substances was carried out using the brands of the stationary phases with the highest ranking positions. Next, a system suitability test as described by the European Pharmacopoeia monograph was performed. Moreover, a study was also performed to achieve a purposeful shortening of the analysis time of the compounds of interest using the selected stationary phases. Finally, it was checked whether methods using core–shell and ultra-high performance liquid chromatographic columns can be an interesting alternative to the high-performance liquid chromatographic method for the analysis of alfuzosin in pharmaceutical practice.

Triacylglycerol in edible oil: Biomarkers for food quality

IntroductionEdible lipids consist of plants oils and animal fats that made up the key components of human diet which is important in the sustenance of life. Triacylglycerol (TAG), a subset of lipid, is the major lipid component in human nutrition. Food quality is important especially for Muslims and vegetarians that consume only Halal food and animal free products, respectively. These products include canned and frozen foods, pastry and certain processed beverages that may contain oils or its derivatives. The quality of said foods can easily be compromised by the addition of food additives, such as oils, that do not follow those requirements. ObjectiveTo perform TAG profiling in various oil standards and commercial cooking oils using ultra high performance liquid chromatography tandem mass spectrometry and to optimize the existing methodology from using a porous-type column to the new core-shell-type column. MethodsThe identification of TAG in various oil standards, commercial cooking oils and marine oils was done by using an established method utilizing a porous C18 1.9 μm column on an ultra pressure liquid chromatography connected to a linear ion trap mass spectrometer with an APCI ion source. The advantages of the core-shell technology were put into test by using a C18 1.7 μm column. Results & DiscussionUnique and characteristic TAGs have been successfully identified in a number of oils samples. For instance in the coconut oil, LOM, MOO, and MLL are examples of unique TAGs. The core-shell column has shortened the total analysis time from 55 minutes to approximately 35 minutes with better peak efficiency and thus improving the resolution. ConclusionUnique TAGs that have been found in various oils have the potential to serve as biomarkers of food quality. The new core-shell column was shown to have several advantages over the porous column.

Synthesis of antibacterial surfaces by plasma grafting of zinc oxide based nanocomposites onto polypropylene

Antibacterial polymer surfaces were designed using ZnO nanoparticles as a bactericide. Mineral encapsulated nanoparticles were grafted onto activated polymer surfaces through their shells. Polypropylene (PP) surfaces were treated using an innovative process coupling core–shell technology and plasma grafting, well-known techniques commonly used to obtain active surfaces for biomedical applications. First, ZnO nanoparticles were encapsulated by (co)polymers: poly(acrylic acid) (PAA) or a poly(methyl methacrylate-co-methacrylic acid) copolymer [P(MMA-MA)]. Second, PP substrates were activated using plasma treatment. Finally, plasma-treated surfaces were immersed in solutions containing the encapsulated nanoparticles dispersed in an organic solvent and allowed to graft onto it. The presence of nanoparticles on the substrates was demonstrated using Fourier-Transform Infrared Spectroscopy (FTIR) analysis, Scanning Electron Microspcopy (SEM)/Energy-Dispersive X-ray (EDX), and Atomic Force Microscopy (AFM) studies. Indeed, the ZnO-functionalized substrates exhibited an antibacterial response in Escherichia coli adhesion tests. Moreover, this study revealed that, surprisingly, native ZnO nanoparticles without any previous functionalization could be directly grafted onto polymeric surfaces through plasma activation. The antibacterial activity of the resulting sample was shown to be comparable to that of the other samples.

Application of core–shell technology for determination of retinol and alpha-tocopherol in breast milk

Breast milk is a main source of fat-soluble vitamins for newborns and it is needful to monitor the nutritional status prior to its application. In this work a novel, high-throughput and low-cost method for monitoring of retinol and alpha-tocopherol in breast milk was developed, validated and compared with reference method using monolithic column.For this purpose five various porous shell and monolithic columns were tested on the basis of relationship between HETP and linear mobile phase velocity, analysis time and consumption of solvents. Finally the core–shell analytical column Kinetex C18 (2.6μm, 100Å, 100×4.6mm) was chosen as the best and optimal values of flow rate, injection volume and temperature of analysis were established.The detection of retinol and alpha-tocopherol was carried out at 325 and 295nm, respectively by diode array detector. The LOD 0.004μmol/L and 0.078μmol/L, the LOQ 0.012μmol/L and 0.182μmol/L for retinol and alpha-tocopherol, respectively were calculated. The validation data showed good linearity, repeatability of retention time with RSD 0.22% and 0.12%, repeatability of peak area with RSD 6.94% and 1.75%, recovery 114.1–116.3% and 99.0–108.6% for retinol and alpha-tocopherol, respectively. Moreover, the newly developed method substantially decreased the solvent consumption by about 263mL per 100 samples with the total time of analysis 1.75min in comparison with analysis time 1.80 of the reference method.

Polyphenolic characterization and chromatographic methods for fast assessment of culinary Salvia species from South East Europe

Although the knowledge and use of several Salvia species (Salvia officinalis, Salvia fruticosa, and Salvia pomifera) can be dated back to Greek Era and have a long history of culinary and effective medicinal use, still there is a remarkable interest concerning their chemistry and especially the polyphenolic composition. Despite the demand in the food and pharmaceutical industry for methods for fast quality assessment of the herbs and spices, even now there are no official requirements for the minimum content of polyphenols in sage covered by current regulations neither the European Pharmacopoeia monographs nor the ISO 11165 standard. In this work a rapid analytical method for extraction, characterization and quantification of the major polyphenolic constituents in Sage was developed. Various extractions (infusion – IE; ultrasound-assisted extraction – USE and microwave-assisted extraction – MWE) were performed and evaluated for their effectiveness. Along with the optimization of the mass-detector and chromatographic parameters, the applicability of three different reverse C18 stationary phases (extra-density bonded, core–shell technology and monolith column) for polyphenolics characterization was evaluated. A comprehensive overview of the very variable polyphenolic composition of 118 different plant samples of 68 populations of wild growing culinary Salvia species (S. officinalis: 101; S. fruticosa: 15; S. pomifera: 2) collected from South East Europe (SEE) was performed using HPLC–DAD–ESI-MSn and more than 50 different compounds were identified and quantified. With this work the knowledge about polyphenols of culinary Sage was expanded thus the possibility for gaining an insight into the chemodiversity of culinary Salvia species in South East Europe was unlocked.

Rapid determination of polycyclic aromatic hydrocarbons in rainwater by liquid–liquid microextraction and LC with core‐shell particles column and fluorescence detection

Liquid-liquid microextraction coupled to LC with fluorescence detection for the determination of Environmental Protection Agency's 16 priority pollutant polycyclic aromatic hydrocarbons in rainwater has been developed. The optimization of the extraction method has involved several parameters, including the comparison between an ultrasonic bath and a magnetic stirrer as extractant apparatus, the choice of the extractant solvent, and the optimization of the extraction time. Liquid-liquid microextraction gave good results in terms of recoveries (from 73.6 to 102.8% in rainwater) and repeatability, with a very simple procedure and low solvent consumption. The reported chromatographic method uses a Core-Shell technology column, with particle size <3 μm instead of classical 5-μm particles column. The resulting backpressure was below 300 bar, allowing the use of a conventional HPLC system rather than the more expensive ultrahigh performance LC (UHPLC). An average decrease of 59% in run time and 75% in eluent consumption has been obtained, compared to classical HPLC methods, keeping good separation, sensitivity, and repeatability. The proposed conditions were successfully applied to the determinations of polycyclic aromatic hydrocarbons in genuine rainwater samples.

Core-Shell Particle Technology in Pharmaceutical Analysis

The column is the heart of chromatographic system, common secret among all chromatographers. This statement is the most impressive that I remember from my early steps using any chromatographic science. But what happens when this heart becomes so hard as a stone? Oppositely to real life consequences, the result is that sensitivity is higher. And this heart of stone makes the life of the chromatographer much more interesting and easier. Yes, you have correctly guessed. I am talking about core shell technology. This technology allows us to achieve ultra high performance liquid chromatography using the conventional equipment available in any laboratory that involves HPLC as routine analytical technique.

C&amp;EN Webinars - Tips &amp; Tricks for HPLC/UHPLC Method Development with Core-Shell Technology

RETURN TO ISSUEPREVAdvertisementNEXTC&EN Webinars - Tips & Tricks for HPLC/UHPLC Method Development with Core-Shell TechnologyCite this: Chem. Eng. News 2012, 90, 47, 49Publication Date (Print):November 19, 2012Publication History Published online29 March 2013Published inissue 19 November 2012https://doi.org/10.1021/cen-09047-ad34Copyright © 2012 Chemical & Engineering NewsArticle Views60Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (680 KB) Get e-Alerts

Protein kinase inhibitor analysis with the core–shell separation technique

Here, we describe the application of the core-shell separation technology in the field of protein kinase inhibitor analysis with the HPLC-diode-array detector (DAD) technique. A Kinetex 2.6 μm C8 100 Å, 150 × 4.6 mm column maintained at 30 ± 1 °C was used for the separation, and further, a connection of two core-shell HPLC columns with a total column dimension of 250 × 4.6 mm was also applied. The analytes were eluted with a mobile phase consisting of 0.05 M H(3)PO(4)/KH(2)PO(4) (pH = 2.3)-acetonitrile (7:3, v/v), with a flow rate of 0.7 mL/min. A liquid-liquid extraction with 1-chlorobutane was used for the sample preparation. The validation of the canertinib analytical method resulted in recoveries in the range of 74-79 % and in relative standard deviation and accuracy lower than 15 %, both for between- and within-batch calculations. A very good linearity in the validated range (5-10,000 ng/mL) and a limit of quantification (LOQ) of 5 ng/mL were achieved. Peak width, height and peak area of six protein kinase inhibitors analysed with a core-shell column and with a conventional fully porous particle column were compared. The results showed that, for most inhibitors analysed with the core-shell analytical column, the peaks were about two to three times narrower and two to three times higher, with areas that remained almost unchanged. The presented study revealed that the application of this separation technology is a very cost-effective way to bring the LOQ of the protein kinase inhibitor analysis with an HPLC closer to the possibilities of the LC-MS/MS technique.

Quantum dots: an insight and perspective of their biological interaction and how this relates to their relevance for clinical use.

Due to their novel physico-chemical characteristics, semi-conductor nanocrystal quantum dots (QDs) provide an advantageous perspective towards numerous different consumer and medical applications. The most notable potential application of QDs is their use as therapeutic and diagnostic tools in nanomedicine. Despite the many benefits posed by QDs, the proposed, intentional exposure to humans has raised concerns towards their potential impact upon human health. These concerns are predominantly based upon the heterogeneous composition of QDs, which most commonly comprises of a cadmium-based core and zinc sulphide shell. Whilst other nanoparticle (NP) types possess a similar structure to QDs (i.e. core-shell technology (e.g. Fe2O3, Au and superparamagnetic iron oxide NPs)), the importance of the concerns surrounding human exposure to QDs is amplified further since, due to the sophisticated chemical and light-emitting properties of QDs, the use of these NPs within any (nano)medical setting/application could be suggested as realistic, rather than simply an advantageous possibility. It is therefore imperative that a thorough understanding of how QDs interact with various biological systems, predominantly those relative to humans and what the consequences of such interactions are is gained with extreme alacrity. It is the aim of this review to highlight the current knowledge base of QD-biological system interactions, where the knowledge gaps (still) remain and how the understanding of this interaction relates to the most notable of applications for QDs; their clinical relevance.

Validation of a method for the analysis of nine quinolones in eggs by pressurized liquid extraction and liquid chromatography with fluorescence detection

A multiresidue method for the analysis, in egg matrices, of residues of nine quinolones used in veterinary medicine, has been developed and validated according to the provisions of Council Decision 2002/657. Compounds were extracted by a pressurized liquid extraction (PLE) technique using a 1:1 mixture of acetonitrile and a phosphoric acid buffer (pH 3.0) at 70°C. The obtained extract was clear enough, so that no further clean-up was necessary. Analytes were determined by liquid chromatography (LC) with fluorescence detection (FL). Two chromatographic columns were compared: a high-purity silica Inertsil C8 column and a newly developed Kinetex C18 core–shell technology column. Validation was carried out at four concentration levels, using both chromatographic columns. Precision in terms of reproducibility standard deviation was between 7% and 23%, and good recoveries were obtained. Decision limit (CCα) and detection capability (CCβ) values obtained with the Inertsil and Kinetex columns were in the 0.2–19.8μgkg−1 and 0.4–33.5μgkg−1 concentration ranges, respectively. The proposed method allows residues of quinolones banned for use with laying hens to be detected and quantified in eggs. About twenty-four samples per day can be processed.

On the use of Kinetex™‐C18 core‐shell 2.6 µm stationary phase to the multiclass determination of antibiotics

Fast and accurate analysis is a prerequisite in all analytical fields especially in food, biological, pharmaceutical, and environmental samples. The new trend of ultra performance liquid chromatography (LC) has the main drawback of expensive instrumentation, which can't be easily found in low-budget analytical laboratories. The evolution of core shell technology has contributed to this direction, since ultra high efficiency can be achieved on common LC instrument platforms. Herein the novel core shell analytical column, KINETEX (™) 2.6 µm, (150 mm × 4.6 mm) was comparatively studied against two conventional reversed-phase silica-based and one monolithic column. Eight antimicrobial agents representing two different classes: penicillins and amphenicols, were separated using a typical 400 bar high performance liquid chromatography (HPLC) equipment. Comparison of column performance was carried out by calculation of the number of theoretical plates N, the tailing factor T(f) , the relative retention time RRT, the retention factor k, the resolution factor R(s) , and the precision of the retention time and peak area. Optimal chromatographic conditions were used to validate the method. Its applicability was proven by the analysis of veterinary drug formulations. The examined antibiotics were well resolved within 17 min. Limit of quantitation values were 25.9 ng for amoxicillin, 14.1 ng for ampicillin, 41.6 ng for thiamphenicol, 9.6 ng for oxacillin, 23.5 ng for florfenicol, 26.7 for cloxacillin, 23.5 ng for chloramphenicol and 42.3 ng for dicloxacillin for 20 µL injection volume. The developed method can be easily and readily transferred to any laboratory.

Synthesis and characterisation of optically tuneable, magnetic phosphors

YVO 4:Eu 3+ phosphor particles have been encapsulated with silica using core–shell technology to produce particles of 400–600 nm in size. The surface of the outer silica shell was further functionalised by the introduction of iron oxide nanoparticles, thus producing a material possessing both magnetic and luminescent properties. The YVO 4:Eu 3+@SiO 2–magnetite composite material was characterised by X-ray diffraction (XRD), Raman and Fourier transform IR spectroscopy, scanning electron microscopy and emission spectroscopy. Characterisation of the outer iron oxide coating with 57Fe Mössbauer spectroscopy, magnetization measurements and scanning electron microscopy reveals the presence of non-stoichiometric maghemite and magnetite nanoparticles of sizes less than ∼20 nm.

Colloidal stability by surface modification

The study of colloids is important in the design of materials for uses ranging from pot making to petroleum refining. This review presents the reasons for instability and different methods for attaining stability in various systems of interest. in this context, both steric and electrostatic stabilization are discussed. Also discussed are surface modification in core-shell technology and the importance of surfactants in emulsions.

Fabrication of silver nanotubes using functionalized silica rod as templates

Silver nanotubes were prepared by the adsorption of silver nanoparticles or ions at the surface of functionalized silica rod, followed by the removal of silica rod by chemical etching process with 10 M HF solution. The surfaces of silica rod were functionalized with silanol, amine or thiol group. The 3-aminopropyltrimethoxysilane (APTMS) and 3-mercaptopropyltrimethoxysilane (MPTMS) were used as functionalizing agents. In the conventional method, the fabrication of silver nanotubes by core-shell technology was not easy due to the difficulties in retaining the shell structures during the core removal process. This limitation was overcome through the method proposed in this study. The major focus of this study is on understanding the mechanism of formation of the silver nanotubes through the self-assembly behavior by the adsorption of silver nanoparticles or ions onto the silica templates. The silver coated silica rods and silver nanotubes were characterized using the field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS).