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1.
Indian J Med Res ; 153(1 & 2): 126-131, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33818469

RESUMO

Background & objectives: Coronavirus disease 2019 (COVID-19) has so far affected over 41 million people globally. The limited supply of real-time reverse transcription-polymerase chain reaction (rRT-PCR) kits and reagents has made meeting the rising demand for increased testing incompetent, worldwide. A highly sensitive and specific antigen-based rapid diagnostic test (RDT) is the need of the hour. The objective of this study was to evaluate the performance of a rapid chromatographic immunoassay-based test (index test) compared with a clinical reference standard (rRT-PCR). Methods: A cross-sectional, single-blinded study was conducted at a tertiary care teaching hospital in north India. Paired samples were taken for RDT and rRT-PCR (reference standard) from consecutive participants screened for COVID-19 to calculate the sensitivity and specificity of the RDT. Further subgroup analysis was done based on the duration of illness and cycle threshold values. Cohen's kappa coefficient was used to measure the level of agreement between the two tests. Results: Of the 330 participants, 77 were rRT-PCR positive for SARS-CoV-2. Sixty four of these patients also tested positive for SARS-CoV-2 by RDT. The overall sensitivity and specificity were 81.8 and 99.6 per cent, respectively. The sensitivity of RDT was higher (85.9%) in participants with a duration of illness ≤5 days. Interpretation & conclusions: With an excellent specificity and moderate sensitivity, this RDT may be used to rule in COVID-19 in patients with a duration of illness ≤5 days. Large-scale testing based on this RDT across the country would result in quick detection, isolation and treatment of COVID-19 patients.


Assuntos
/diagnóstico , Cromatografia , Imunoensaio , Estudos Transversais , Humanos , Índia , Sensibilidade e Especificidade
2.
Int J Mol Sci ; 22(6)2021 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-33809562

RESUMO

Adzuki seed ß-vignin, a vicilin-like globulin, has proven to exert various health-promoting biological activities, notably in cardiovascular health. A simple scalable enrichment procedure of this protein for further nutritional and functional studies is crucial. In this study, a simplified chromatography-independent protein fractionation procedure has been optimized and described. The electrophoretic analysis showed a high degree of homogeneity of ß-vignin isolate. Furthermore, the molecular features of the purified protein were investigated. The adzuki bean ß-vignin was found to have a native size of 146 kDa, and the molecular weight determined was consistent with a trimeric structure. These were identified in two main polypeptide chains (masses of 56-54 kDa) that are glycosylated polypeptides with metal binding capacity, and one minor polypeptide chain with a mass 37 kDa, wherein these features are absent. The in vitro analysis showed a high degree of digestibility of the protein (92%) and potential anti-inflammatory capacity. The results lay the basis not only for further investigation of the health-promoting properties of the adzuki bean ß-vignin protein, but also for a possible application as nutraceutical molecule.


Assuntos
Cromatografia/métodos , Proteínas de Plantas/genética , Vigna/química , Sequência de Aminoácidos , Células CACO-2 , Fracionamento Químico , Farinha , Globulinas/química , Humanos , Concentração de Íons de Hidrogênio , Inflamação/patologia , Proteínas de Plantas/química , Proteínas de Plantas/isolamento & purificação , Sementes/química , Solubilidade
3.
Adv Exp Med Biol ; 1280: 149-159, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33791980

RESUMO

Ion chromatography (IC) represents an important technique for separation of charged and polar compounds. Traditionally, IC is often used for the analysis of small inorganic ions. Due to the development of eluent suppression technology that allows continuous online desalting and conversion of high-salt eluents into pure water, IC has been coupled with mass spectrometry (MS) for the analysis of more diverse range of anionic and cationic analytes. Recent studies have demonstrated that IC-MS is a powerful technique with exquisite detection sensitivity, high reproducibility, and quantitative capability for metabolomic analysis. In this chapter, we provide a brief overview of IC principles and IC-MS for metabolomic analysis.


Assuntos
Cromatografia , Metabolômica , Íons , Espectrometria de Massas , Reprodutibilidade dos Testes
4.
J Chromatogr A ; 1643: 462042, 2021 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-33761434

RESUMO

This review specifically examines the development of sample preparation methods for residue analyses of neonicotinoid insecticides in agricultural and environmental matrices. Pesticide residue analysis is fundamentally important to ensure the safety of foods and processed foods of plant and animal origin, and to preserve the environment, particularly soil and water. For the development of pesticide residue analysis, the sample preparation process is an important key to maximizing the analytical performance of highly sensitive and accurate chromatographic instruments and to acquiring reliable analytical results. This review outlines sample preparation methods that have been proposed to date for extraction of neonicotinoids that might remain in a complicated sample matrix in quantitatively trace amounts, and for cleaning up, to the greatest extent possible, the interfering components that coexist in the sample extract.


Assuntos
Agricultura , Métodos Analíticos de Preparação de Amostras , Cromatografia/métodos , Poluentes Ambientais/análise , Neonicotinoides/análise , Animais , Poluentes Ambientais/química , Neonicotinoides/química , Resíduos de Praguicidas/análise
5.
J Chromatogr A ; 1642: 462010, 2021 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-33652368

RESUMO

Evaluation of the chromatographic properties of covalently bonded hyperbranched stationary phase based on poly(styrene-divinylbenzene) (PS-DVB) and containing zwitterionic fragments in the structure of functional layer was conducted in suppressed ion chromatography (IC), reversed phase high performance liquid chromatography (RP HPLC), and hydrophilic interaction liquid chromatography (HILIC) modes. Besides the possibility of resolving 20 inorganic anions and organic acids using KOH eluent in suppressed IC, prepared resin provided the separation of alkylbenzenes in RP HPLC, water-soluble vitamins, amino acids, and sugars in HILIC mode. Trends in the retention of hydrophobic and polar analytes on the prepared stationary phase indicated the dominating effect of analyte nature on the retention mechanism and proved satisfactory hydrophilization of PS-DVB surface with hyperbranched functional layer for retaining polar compounds. The obtained results revealed good prospects of using hydrophobic PS-DVB substrate for preparing stationary phases for mixed-mode chromatography.


Assuntos
Cromatografia/métodos , Poliestirenos/química , Aminoácidos/isolamento & purificação , Cromatografia de Fase Reversa , Interações Hidrofóbicas e Hidrofílicas , Açúcares/isolamento & purificação , Vitaminas/isolamento & purificação
6.
J Chromatogr A ; 1642: 462023, 2021 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-33714081

RESUMO

Mass spectrometry is now in widespread use for the detection of the analytes separated by chromatography. Electron ionization is the most frequently used method in mass spectrometry. However, this ionization technique sometimes suffers from extensive fragmentation of analytes, which makes identification difficult. A photoionization technique has been developed for suppressing this fragmentation and for subsequently observing a molecular ion. A variety of lasers have been employed for the sensitive and selective ionization of organic compounds. A femtosecond laser has a high peak power and is preferential for efficient ionization as well as for suppressing fragmentation, providing valuable information concerning molecular weight and chemical structure as well. In this review, we report on applications of femtosecond ionization mass spectrometry combined with gas chromatography.


Assuntos
Cromatografia/métodos , Espectrometria de Massas/métodos , Cromatografia Gasosa-Espectrometria de Massas , Hidrocarbonetos Policíclicos Aromáticos/análise , Análise Espectral Raman , Termodinâmica
7.
J Chromatogr A ; 1642: 462033, 2021 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-33714774

RESUMO

Multiple-open-tubular columns enabling transverse diffusion (MOTTD) are made of straight, parallel, and cylindrical flow channels separated by a mesoporous stationary phase. In Part 1, a model of band broadening along MOTTD columns accounting for longitudinal diffusion, the trans-channel velocity bias, and mass transfer resistance in the stationary phase was proposed and validated. In this Part 2, the model is completed by considering the impact of short-range inter-channel velocity biases on the MOTTD plate number. These velocity biases are caused by the wide distribution of the channel diameters. Different ratios, ρ, of the average inner diameter, 2, of the flow channels to their closest center-to-center distance d (d= 5 µm, ρ= 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, and 0.9) with a relative standard deviation (RSD) increasing from 0 to 50% are considered. The zone retention factor k1 was increased from 1 to 25. The complete model of band broadening is validated after adjustment to dispersion data obtained by 1) the lattice-Boltzmann method for modeling fluid flow, 2) a random-walk particle-tracking (RWPT) technique to address advective-diffusive transport, and 3) by considering two distinct populations of flow channels (inner radii rc,1=(1-RSD) and rc,2=(1+RSD)) arranged at the nodes of a hexagonal compact array. The completed model of band broadening in MOTTD columns reveals that the RSD of the channel diameters has only a moderate impact on the optimum plate number of MOTTD columns: the relative increase of the minimum plate height do not exceed 30% even for the largest RSDs. However, when the mass transfer of the analyte is governed by its slow rate of transverse diffusion across the MOTTD column, the plate height can be increased by up to 100% at high average velocities. Regarding the best trade-off between analysis speed and column performance at a fixed pressure drop of 400 bar, irrespective of the zone retention factor and RSD of the distribution of the channel diameters, the fastest analyses are recommended for MOTTD columns having a small structural parameter ρ. In contrast, for the longest analysis times, the largest values of ρ are required to maximize the performance of MOTTD columns.


Assuntos
Cromatografia/instrumentação , Simulação por Computador , Difusão , Cinética
8.
Carbohydr Polym ; 261: 117866, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33766354

RESUMO

Almost all plant cells are surrounded by a wall constructed of co-extensive networks of polysaccharides and proteoglycans. The capability to analyse cell wall components is essential for both understanding their complex biology and to fully exploit their numerous practical applications. Several biochemical and immunological techniques are used to analyse cell walls and in almost all cases the first step is the preparation of an alcohol insoluble residue (AIR). There is significant variation in the protocols used for AIR preparation, which can have a notable impact on the downstream extractability and detection of cell wall components. To explore these effects, we have formally compared ten AIR preparation methods and analysed polysaccharides subsequently extracted using high-performance anion exchange chromatography (HPAEC-PAD) and Micro Array Polymer Profiling (MAPP). Our results reveal the impact that AIR preparation has on downstream detection of cell wall components and the need for optimisation and consistency when preparing AIR.


Assuntos
Parede Celular/química , Técnicas de Química Analítica/métodos , Células Vegetais/química , Polissacarídeos/isolamento & purificação , Arabidopsis/química , Membrana Celular/química , Cromatografia/métodos , Análise em Microsséries , Folhas de Planta/química , Preparações de Plantas/isolamento & purificação , Caules de Planta/química , Polímeros/análise , Polímeros/isolamento & purificação , Polissacarídeos/química , Tabaco/química
9.
Molecules ; 26(4)2021 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-33669919

RESUMO

With the rapid development of global industry and increasingly frequent product circulation, the separation and detection of chiral drugs/pesticides are becoming increasingly important. The chiral nature of substances can result in harm to the human body, and the selective endocrine-disrupting effect of drug enantiomers is caused by differential enantiospecific binding to receptors. This review is devoted to the specific recognition and resolution of chiral molecules by chromatography and membrane-based enantioseparation techniques. Chromatographic enantiomer separations with chiral stationary phase (CSP)-based columns and membrane-based enantiomer filtration are detailed. In addition, the unique properties of these chiral resolution methods have been summarized for practical applications in the chemistry, environment, biology, medicine, and food industries. We further discussed the recognition mechanism in analytical enantioseparations and analyzed recent developments and future prospects of chromatographic and membrane-based enantioseparations.


Assuntos
Praguicidas/isolamento & purificação , Preparações Farmacêuticas/isolamento & purificação , Fracionamento Químico , Cromatografia , Praguicidas/química , Preparações Farmacêuticas/química , Estereoisomerismo
10.
J Chromatogr A ; 1641: 461992, 2021 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-33706165

RESUMO

Stereoisomeric determination of individual triacylglycerols (TAGs) in natural oils and fats is a challenge due to similar physicochemical properties of TAGs with different fatty acid combinations. In this study, we present a strategy to resolve the enantiomeric composition of nutritionally important TAGs in sea buckthorn (Hippophaë rhamnoides) as an example food matrix. The targeted strategy combines 1) fatty acid profiling with GC, 2) separation of TAGs with RP-HPLC, 3) stereospecific separation with chiral-phase HPLC and 4) structural characterization with MS. Three major asymmetric diacid- and triacid-TAG species were analyzed in sea buckthorn pulp oil. Off-line coupling of RP-HPLC and chiral-phase HPLC allowed separation of several TAG regioisomers and enantiomers, which could not be resolved using one-dimensional techniques. Enantiomeric ratios were determined and specific structural analysis of separated TAGs was performed using direct inlet ammonia negative ion chemical ionization method. Of the TAG 16:0/16:1/16:1 palmitic acid (C16:0) was located predominantly in a primary position and the enantiomeric ratio of TAG sn-16:1-16:1-16:0 to sn-16:0-16:1-16:1 was 70.5/29.5. Among the TAGs 16:0/16:0/18:2 and 16:0/16:0/16:1, only ca 5% had C16:0 in the sn-2 position, thus, ca 95% were symmetric sn-16:0-18:2-16:0 and sn-16:0-16:1-16:0. The enantiomeric ratio of triacid-TAGs containing C16:0 and two unsaturated fatty acids (palmitoleic C16:1, oleic C18:1 or linoleic acids C18:2) could not be resolved due to lack of commercial enantiopure reference compounds. However, it became clear that the targeted strategy presented offer unique and convenient method to study the enantiomeric structure of individual TAGs.


Assuntos
Cromatografia/métodos , Espectrometria de Massas/métodos , Triglicerídeos/química , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia de Fase Reversa , Ácidos Graxos/análise , Hippophae/química , Óleos/análise , Estereoisomerismo
11.
Zhongguo Zhong Yao Za Zhi ; 46(6): 1430-1437, 2021 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-33787141

RESUMO

To study phenylpropanoids from Eleocharis dulcis and their hepatoprotective activities. The compounds were separated and purified from ethyl acetate part by conventional column chromatography and preparative liquid chromatography, and their structures were identified by various spectral techniques. The HL-7702 cells damage model of hepatocytes induced by APAP was used to screen and evaluate the hepatoprotective activities of these compounds. Sixteen compounds were isolated from ethyl acetate part of E. dulcis, and their structures were identified as 6'-(4″-hydroxy-3″-methoxy-phenylpropenyl)-1-(10-methoxy-phenylacetone)-1'-O-ß-D-glucopy-ranoside(1), susaroyside A(2), clausenaglycoside B(3), clausenaglycoside C(4), clausenaglycoside D(5), emarginone A(6), emarginone B(7), thoreliin B(8), 4-O-(1',3'-dihydroxypropan-2'-yl)-dihydroconiferyl alcohol 9-O-ß-D-glucopyranoside(9), 2-[4-(3-methoxy-1-propenyl)-2-methoxy-phenoxy]-propane-1,3-diol(10), 6'-O-(E-cinnamoyl)-coniferin(11), methyl 3-(2-O-ß-D-glucopyranosyl-3,4,5,6-tetramethoxyphenyl) propanoate(12), clausenaglycoside A(13), 9-O-(E-cinnamoyl)-coniferin(14), 6'-O-(E-cinnamoyl)-syringin(15), 2'-O-(E-cinnamoyl)-syringin(16). Among them, compound 1 was a new compound. Compounds 2-16 were isolated from this plant for the first time. Among them, compounds 2 and 8 showed certain hepatoprotective activities.


Assuntos
Eleocharis , Cromatografia , Hepatócitos , Extratos Vegetais
12.
J Chromatogr A ; 1639: 461919, 2021 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-33535114

RESUMO

The first CE methodology enabling the enantiomeric separation of panthenol was developed in this work. Electrokinetic chromatography with cyclodextrins (CD-EKC) was the CE mode employed for this purpose. The effect of different experimental variables such as the nature and concentration of the cyclodextrin, the temperature and the separation voltage was investigated. The best enantiomeric separation was obtained with 25 mM (2-carboxyethyl)-ß-CD (CE-ß-CD) in 100 mM borate buffer (pH 9.0), with a separation voltage of 30 kV and a temperature of 30 °C. Under these conditions, an enantiomeric resolution of 2.0 in an analysis time of 4.2 min was obtained, being the biologically active enantiomer d-panthenol (dexpanthenol) the second-migrating enantiomer. The analytical characteristics of the method were evaluated in terms of precision, accuracy, selectivity, linearity, LOD, and LOQ, showing a good performance for the quantitation of dexpanthenol in cosmetic and pharmaceutical formulations. The enantiomeric impurity (L-panthenol) could be detected at a 0.1% level with respect to the majority enantiomer, allowing to accomplish the requirements of the ICH guidelines. The method was also successfully applied to study the stability of panthenol under abiotic and biotic conditions and its toxicity on non-target organisms (the aquatic plant Spirodela polyrhiza).


Assuntos
Eletroforese Capilar/métodos , Ácido Pantotênico/análogos & derivados , Testes de Toxicidade , Araceae/efeitos dos fármacos , Cromatografia , Cosméticos/análise , Ciclodextrinas/química , Limite de Detecção , Ácido Pantotênico/química , Ácido Pantotênico/isolamento & purificação , Ácido Pantotênico/toxicidade , Preparações Farmacêuticas/análise , Estereoisomerismo
13.
J Chromatogr A ; 1639: 461918, 2021 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-33540182

RESUMO

A literature update has been done concerning Deep Eutectic Solvents (DES) use in chromatography applications. The literature survey was based on the period from 2010 till 2020 and manuscripts reported in the data bases Web of Science and Scopus. The use of DES as mobile phase and mobile phase additives, stationary phases and solid phase modifiers and the use of DES as reaction solvents for chromatography use, were evaluated. Emphasis was placed on the differentiation of DES and Ionic Liquids (ILs) and the advanced green characteristics of the new solvents as compared with traditional organic solvents and ILs with a look into the drawbacks and future perspectives in the field of separation methods.


Assuntos
Cromatografia/métodos , Solventes/química , Líquidos Iônicos/química
14.
J Chromatogr A ; 1639: 461916, 2021 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-33548663

RESUMO

Cell membrane chromatography (CMC) is a biomimetic chromatographic method based on the ability of membrane receptors to selectively interact with their ligands in vivo. Using membrane receptors as a stationary phase, the CMC method helps in determining the binding characteristics between ligands and membrane receptors and in efficiently identifying specific target components in a complex sample that produce the cellular biological effects of ligands (drugs, antibodies, enzymes, cytokines, etc.). CMC is an analytical tool for revealing characteristics of ligand-receptor interactions, screening and discovering target substances, and accurately controlling the quality of drugs. Since establishment of CMC in the early 1990s, with the rapid development of cell biology, significant progress has been made in the development of high-expression receptors, engineered cell cultures, and standardized preparations, which allowed in vitro immobilization of cell membrane receptors and miniaturization of binding assays. A variety of CMC models have been established using different membrane receptors as a stationary phase, and many new methods have been developed by combining CMC with high-performance liquid chromatography (HPLC)/mass spectrometry or HPLC-IT-TOF technologies. CMC methods have been widely used to study drug-receptor interactions and to screen complex samples for effective or harmful components.


Assuntos
Membrana Celular/química , Cromatografia/métodos , Medicamentos de Ervas Chinesas/análise , Humanos , Cinética , Espectrometria de Massas , Receptores de Superfície Celular/química
15.
J Chromatogr A ; 1640: 461931, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33581675

RESUMO

The average minimum resolution required for separating adjacent single-component peaks (SCPs) in one-dimensional chromatograms is an important metric in statistical overlap theory (SOT). However, its value changes with changing chromatographic conditions in non-intuitive ways, when SOT predicts the average number of peaks (maxima). A more stable and easily understood value of resolution is obtained on making a different prediction. A general equation is derived for the sum of all separated and superposed widths of SCPs in a chromatogram. The equation is a function of the saturation α, a metric of chromatographic crowdedness, and is expressed in dimensionless form by dividing by the duration of the chromatogram. This dimensionless function, f(α), is also the cumulative distribution function of the probability of separating adjacent SCPs. Simulations based on the clustering of line segments representing SCPs verify expressions for f(α) calculated from five functions for the distribution of intervals between adjacent SCPs. Synthetic chromatograms are computed with different saturations, distributions of intervals, and distribution of SCP amplitudes. The chromatograms are analyzed by calculating the sum of the widths of peaks at different relative responses, dividing the sum by the duration of the chromatograms, and graphing the reduced sum against relative response. For small values of relative response, the reduced sum approaches the fraction of baseline that is occupied by chromatographic peaks. This fraction can be identified with f(α), if the saturation α is defined with the average minimum resolution equaling 1.5. The identification is general and is independent of the saturation, the interval distribution, or the amplitude distribution. This constant value of resolution corresponds to baseline resolution, which simplifies the interpretation of SOT.


Assuntos
Cromatografia/métodos , Estatística como Assunto , Simulação por Computador , Probabilidade
16.
J Vis Exp ; (167)2021 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-33522504

RESUMO

High demand for antibodies as therapeutic interventions for various infectious, metabolic, autoimmune, neoplastic, and other diseases creates a growing need in developing efficient methods for recombinant antibody production. As of 2019, there were more than 70 FDA-approved monoclonal antibodies, and there is exponential growth potential. Despite their promise, limiting factors for widespread use are manufacturing costs and complexity. Potentially, plants offer low-cost, safe, and easily scalable protein manufacturing strategies. Plants like Nicotiana benthamiana not only can correctly fold and assemble complex mammalian proteins but also can add critical post-translational modifications similar to those offered by mammalian cell cultures. In this work, by using native GFP and an acid-stable variant of green fluorescent protein (GFP) fused to human monoclonal antibodies, we were able to visualize the entire transient antibody expression and purification process from N. benthamiana plants. Depending on the experiment's purpose, native GFP fusion can ensure easier visualization during the expression phase in the plants, while acid-stable GFP fusion allows for visualization during downstream processing. This scalable and straightforward procedure can be performed by a single researcher to produce milligram quantities of highly pure antibody or antibody fusion proteins in a matter of days using only a few small plants. Such a technique can be extended to the visualization of any type of antibody purification process and potentially many other proteins, both in plant and other expression systems. Moreover, these techniques can benefit virtual instructions and be executed in a teaching laboratory by undergraduate students possessing minimal prior experience with molecular biology techniques, providing a foundation for project-based exploration with real-world applications.


Assuntos
Imunoglobulina G/biossíntese , Proteínas Recombinantes de Fusão/biossíntese , Tabaco/genética , Agrobacterium tumefaciens/metabolismo , Animais , Anticorpos Monoclonais/metabolismo , Sequência de Bases , Cromatografia , Eletroforese em Gel de Poliacrilamida , Proteínas de Fluorescência Verde/metabolismo , Humanos , Canamicina/farmacologia , Folhas de Planta/microbiologia , Plantas Geneticamente Modificadas , Tabaco/crescimento & desenvolvimento , Tabaco/microbiologia , Raios Ultravioleta
17.
J Chromatogr A ; 1641: 461968, 2021 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-33611116

RESUMO

The adoption of process analytical technologies by the biopharmaceutical industry can reduce the cost of therapeutic drugs and facilitate investigation of new bioprocesses. Control of critical process parameters to retain critical product quality attributes within strict bounds is important for ensuring a consistently high product quality, but developing the sophisticated analytical technologies required has proven to be a major challenge. Here, we demonstrate a new optical technique for continuous monitoring of protein species as they are eluted from a chromatographic column, even when they fully co-elute with other protein species, without making any assumption about or peak-fitting to the elution profile. To achieve this, we designed and constructed a time-resolved intrinsic fluorescence lifetime chromatograph, and established an analytical framework for deconvolving and quantifying distinct but co-eluting protein species in real time. This proof-of-concept technology has potentially useful applications as a process analytical technology and more generally as an analytical technique for label-free quantification of proteins in mixtures.


Assuntos
Cromatografia/instrumentação , Fenômenos Ópticos , Estudo de Prova de Conceito , Proteínas/análise , Fluorescência , Ovalbumina/análise , Soroalbumina Bovina/análise
18.
J Chromatogr A ; 1641: 461999, 2021 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-33611122

RESUMO

Low molecular weight diglycolamide (DGA) extractants were tested for the extraction of europium(III) and americium(III) from nitric acid solutions in n-dodecane, a molecular diluent and 1-butyl-3-methylimidazolium bis(trifluoromethanesulphonyl) imide (C4mim⋅NTf2), a room temperature ionic liquid, as the diluents. N,N,N',N'-tetra-n-butyl diglycolamide (TBDGA) was selected for extraction chromatography (XC) studies involving Eu(III) and Am(III). While the TBDGA resin containing n-dodecane gave reasonably high Kd values, that containing the ionic liquid showed higher Eu(III) uptake values. Compared to Eu(III), Am(III) was extracted by the resins to a lower extent. The loaded Eu(III) was back extracted from the resin using 0.05 M EDTA solutions in a buffered medium containing 1 M guanidine carbonate. Reusability studies indicated that, while the ionic liquid-based resin can be conveniently recycled five times with very marginal decrease in the percentage extraction values, there was a sharp decrease in the percent extraction after three cycles with the n-dodecane-based resin. The uptake data was fitted into different isotherm models and the results conformed to the Langmuir model. Based on the batch uptake studies, columns were prepared and the breakthrough as well as elution profiles were obtained. The elution profiles were found to be sharp without any significant tailing.


Assuntos
Cromatografia/métodos , Glicolatos/química , Líquidos Iônicos/química , Ácido Nítrico/química , Resinas Sintéticas/química , Amerício/química , Cátions , Európio/química , Imidazóis/química , Ligantes , Solventes/química , Temperatura , Termogravimetria , Fatores de Tempo
19.
J Chromatogr A ; 1641: 461991, 2021 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-33640805

RESUMO

The importance of yeasts in aroma production during wine fermentation is a significant concern for obtaining a wine that appraises a broad number of consumers. For wine producers, wine aroma modulation is an essential issue where the yeasts used during the winemaking process represents a feasible way to improve the complexity and enhance wines specific characteristics. During the fermentation process of wines, yeasts convert grapes sugars into alcohol, carbon dioxide and a large number of secondary metabolites, depending on yeast metabolism, affecting the wine composition, namely its aroma and amino acids (AAs) composition. So, the present work aims to study the effect of different Saccharomyces-type yeasts on the AAs composition and volatile profile of Arinto white wines. To pursue this goal, four white wines from Arinto grapes were fermented with three different commercial yeasts (Saccharomyces bayanus EC1118, Saccharomyces cerevisiae CY3079, Saccharomyces bayanus QA23) and one Native yeast. Arinto wines AAs composition was quantified by HPLC-DAD, after a derivatization step to obtain the aminoenone derivatives. The volatile content of Arinto wines was determined by GC/MS, after an HS-SPME extraction. Results showed significant differences among the AAs content and volatile profile in the Arinto wines. The higher AAs content was found in the Arinto wines fermented with the CY3079 yeast (470.74 mg•L-1), and the lowest content of AAs in the Arinto wines fermented with EC1118 yeast (343.06 mg•L-1). Native yeast results in wines with a volatile profile richer in esters compared to the other sample wines. Principal component analysis (PCA) obtained with combined data of AAs and volatile compounds, after normalization, for each Arinto wine samples, shows a clear separation of wines fermented with Native and CY3079 yeasts in relation to QA23 and EC1118 fermented wines . The first and second principal components are responsible for 44.40% and 32.20%, respectively, of the system's variance, which clearly showed a differentiation among wines.


Assuntos
Aminoácidos/análise , Cromatografia/métodos , Saccharomyces/metabolismo , Compostos Orgânicos Voláteis/análise , Vinho/microbiologia , Fermentação , Cromatografia Gasosa-Espectrometria de Massas , Odorantes/análise , Análise de Componente Principal , Reprodutibilidade dos Testes , Saccharomyces cerevisiae/metabolismo , Vitis/química , Volatilização
20.
J Chromatogr A ; 1640: 461948, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33561708

RESUMO

Fast-throughput and cost reduction of current purification platforms are becoming increasing requests during antibody manufacture. The macroporous-matrix absorbents have presented extensive potentiality in improving operational throughput during purification of macromolecule. And meanwhile the peptide ligand has become a promising alternative to recombinant protein ligands for cost reduction of chromatographic purification. Therefore, here we designed a functionalized microspheres resin with both macroporous matrix of polymerized glycidyl methacrylate and ethylene glycol dimethacrylate (PGMA-EDMA) and peptide ligand of hexapeptide (FYEILH). In order to circumvent the steric effect of peptides and amplify the binding sites on macroporous matrix, the peptide ligand was coupled on a liner PGMA polymer brushes grafted on microspheres. Comparing to the conventional agarose-matrix resin and the general peptide-grafted microspheres, the functionalized microspheres presented excellent permeability and high capacity to rapid loading hIgG by maintaining a stable level of dynamic binding capacity at fast flow rate above 110 column volume per hour (cv/h) and very short residence time below 0.5 min. Such functionalized microspheres provide a facile and broadly applicable strategy to develop the attractive candidate for rapid and cost-reduced purification of antibody.


Assuntos
Anticorpos Monoclonais/isolamento & purificação , Imunoglobulina G/isolamento & purificação , Microesferas , Peptídeos/química , Polímeros/química , Adsorção , Animais , Células CHO , Cromatografia , Cricetulus , Difusão , Humanos , Ligantes , Permeabilidade , Polimerização , Porosidade , Domínios Proteicos , Proteínas Recombinantes/química , Resinas Sintéticas/química , Sefarose/química , Soroalbumina Bovina/química , Proteína Estafilocócica A/química , Propriedades de Superfície
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