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1.
Food Chem ; 335: 127649, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32738538

RESUMO

Rosa rugosa Thunb. seed oil (RR) extracted by supercritical CO2 was investigated. RR chemical composition, radical scavenging effect and oxidative stability were evaluated. RR aqueous emulsions were examined for cell cytotoxicity, proliferation, redox state and migration using mouse embryonic fibroblast Balb/3T3, human dermal fibroblast NHDF cell lines, and on neoplastic cell lines: acute monocytic leukemia THP-1 and lung adenocarcinoma A549. RR total contents of phytosterols, tocopherols, carotenoids and phenolics were 10115.23, 784.16, 40.32 and 10.30 mg/kg, respectively. Rich antioxidant composition of RR was reflected in its high antioxidant activity (2.1 mM/kg Trolox equivalent) as well as oxidative stability (activation energy 105.6 kJ/mol). The RR emulsions led to marked augmentation of the total cell protein content in BALB/3T3 and NHDF cultures, inhibited cancer cell migration and reduced ROS formation. The studied RR oil proved to have a remarkable combination of bioactive compounds and to exert an antioxidative and chemopreventive effects.


Assuntos
Óleos Vegetais/química , Óleos Vegetais/farmacologia , Rosa/química , Animais , Antioxidantes/química , Antioxidantes/isolamento & purificação , Antioxidantes/farmacologia , Dióxido de Carbono/química , Carotenoides/química , Carotenoides/isolamento & purificação , Carotenoides/farmacologia , Linhagem Celular , Cromatografia com Fluido Supercrítico , Humanos , Camundongos , Oxirredução , Fenóis/química , Fenóis/isolamento & purificação , Fenóis/farmacologia , Fitosteróis/química , Fitosteróis/isolamento & purificação , Fitosteróis/farmacologia , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Óleos Vegetais/isolamento & purificação , Sementes/química , Tocoferóis/química , Tocoferóis/isolamento & purificação , Tocoferóis/farmacologia
2.
Food Chem ; 338: 127724, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32795878

RESUMO

Peppermint is widely used medicinal plant with distinguished bioactive potential, therefore, the aim of present work was to develop novel peppermint extracts with high activity by application of traditional and emerging separation techniques. Conventional hydrodistillation and microwave-assisted hydrodistillation (MWHD) were applied for recovery of essential oil (EO), while organic solvent extraction using Soxhlet apparatus, microwave-assisted and ultrasound-assisted process and supercritical fluid extraction (SFE) were applied for non-selective recovery of peppermint lipophilic extracts. Extracts were characterized in terms of terpenoids profile with special emphasis on content of major compounds (mentol, menthone, isomenthol and eucalyptol). Antioxidant activity (DPPH, ABTS, CUPRAC, FRAP, chelating and phosphomolybdenum assay) and enzyme-inhibitory assays (acetylcholinesterase, butyrylcholinesterase, tyrosinase, amylase and glucosidase inhibition) were used for screening of peppermint bioactivity. MWHD was recognized as alternative for traditional process in EO recovery, while SFE extracts were useful for green production of solvent-free peppermint extracts rich in terpenoids and other lipophilic bioactives.


Assuntos
Antioxidantes/química , Inibidores Enzimáticos/química , Mentha piperita/química , Óleos Voláteis/química , Extratos Vegetais/química , Acetilcolinesterase/química , Acetilcolinesterase/metabolismo , Cromatografia com Fluido Supercrítico , Inibidores Enzimáticos/metabolismo , Mentha piperita/metabolismo , Micro-Ondas , Polifenóis/química , Polifenóis/isolamento & purificação , Análise de Componente Principal , Sonicação , Terpenos/química , Terpenos/isolamento & purificação
3.
Food Chem ; 334: 127595, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32711277

RESUMO

The present study report on the application of an on line supercritical fluid extraction-supercritical fluid chromatography-triple quadrupole/mass spectrometry methodology to the first apocarotenoids profiling of seventeen different chilli peppers cultivars belonging to Capsicum annuum, Capsicum baccatum and Capsicum chinense species. A total of 19 free apocarotenoids and 8 apocarotenoids fatty acid esters were identified; ß-Apo-8'-carotenal and Apo-8'-zeaxanthinal were also quantified and the ß-Apo-8'-carotenal occurrence was in the percentage ranges relative to ß-carotene of 0.03-3.87%. PCA was performed as a multivariate display method on the quantified carotenoids and apocarotenoids, in order to visualize the data structure. Moreover, different ε-apoluteinals and 4-oxo-apo-ß-carotenals were detected in Capsicum species also for the first time and, to the best of authors knowledge, in any food matrix.


Assuntos
Capsicum/química , Carotenoides/análise , Cromatografia com Fluido Supercrítico/métodos , Análise de Alimentos/métodos , Análise de Alimentos/estatística & dados numéricos , Frutas/química , Espectrometria de Massas/métodos , Análise de Componente Principal , beta Caroteno/análise
4.
Food Chem ; 338: 128074, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32950011

RESUMO

A separation and analysis method of fosthiazate stereoisomers was established utilizing supercritical fluid chromatography-tandem mass spectrometry (SFC-MS/MS) with a CHIRALPAK AD-3 column. The determination of the four fosthiazate stereoisomers could be completed within 6 min. The environmental behaviors of fosthiazate stereoisomers were studied in legume vegetables. After applying fosthiazate granules to soil, the concentrations of fosthiazate stereoisomers in the legume vegetables increased with time, reached maximum values in 7-10 days, and then decreased gradually in all legumes except for in Glycine max. No obvious dissipation behaviors were observed in Glycine max. Interestingly, the stereoselective behaviors were species-specific. A-(-), B-(-) and B-(±)-fosthiazate were preferentially enriched in Phaseolus vulgaris Linn and Vigna unguiculata, while A-(+) and A-(±)-fosthiazate preferentially accumulated in Vicia faba Linn, Pisum sativum Linn and G. max. The opposite stereoselectivity of B-(±)-fosthiazate was observed in different growth stage of G. max. No stereoselective dissipation occurred in soil.


Assuntos
Fabaceae/química , Compostos Organofosforados/química , Espectrometria de Massas em Tandem/métodos , Tiazolidinas/química , Cromatografia com Fluido Supercrítico , Fabaceae/metabolismo , Ervilhas/química , Ervilhas/metabolismo , Phaseolus/química , Phaseolus/metabolismo , Soja/química , Soja/metabolismo , Estereoisomerismo , Vicia faba/química , Vicia faba/metabolismo
5.
J Chromatogr A ; 1635: 461770, 2021 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-33310280

RESUMO

Plant extraction has existed for a long time and is still of interest. Due to technological improvements, it is now possible to obtain extracts with higher yields. While global yield is a major parameter because it assesses the extraction performance, it can be of interest to focus on the extraction of particular compounds (specific metabolites) to enrich the sample and to avoid the extraction of unwanted ones, for instance the primary metabolites (carbohydrates, triacylglycerols). The objective then is to improve extraction selectivity is then considered. In solid-liquid extraction, which is often called maceration, the solvent has a major impact on selectivity. Its polarity has a direct influence on the solutes extracted, related to the chemical structure of the compounds, and modelling compound/solvent interactions by using various polarity or interaction scales is a great challenge to favor the choice of the appropriate extracting liquid. Technical advances have allowed the development of recent, and sometimes green, extraction techniques, such as Microwave-Assisted Extraction (MAE), Ultrasound-Assisted Extraction (UAE), Pressurized Liquid Extraction (PLE) and Supercritical Fluid Extraction (SFE). This review focuses on the specificity of these recent techniques and the influence of their physical parameters (i.e. pressure, intensity, etc.). In addition to the solvent selection, which is of prime interest, the physical parameters applied by the different techniques influence the extraction results in different ways. Besides, SFE is a versatile and green technique suitable to achieve selectivity for some compounds. Due to its properties, SC-CO2 allows tailoring conditions to improve the selectivity.


Assuntos
Técnicas de Química Analítica/métodos , Extratos Vegetais/isolamento & purificação , Plantas/química , Técnicas de Química Analítica/instrumentação , Cromatografia com Fluido Supercrítico , Extratos Vegetais/química , Solventes/química
6.
J Chromatogr A ; 1634: 461661, 2020 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-33166894

RESUMO

A robust supercritical chromatography (SFC) method using an Enantiocel C2-5 column was developed for the multigram separation of the enantiomers of hydroxychloroquine (HCQ), affirming its use as a scalable technology and ability to provide quantities of each enantiomer for clinical evaluation. The enantiomers of HCQ were collected on a gram scale with greater than 99% enantiomeric excess. The S and R enantiomer elution order was confirmed using optical rotation determinations with comparison to previously determined assignments.


Assuntos
Técnicas de Química Analítica , Cromatografia com Fluido Supercrítico , Hidroxicloroquina/isolamento & purificação , Estereoisomerismo
7.
J Chromatogr A ; 1633: 461646, 2020 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-33166744

RESUMO

Chromatographic parameters have been evaluated regarding the supercritical fluid chromatography of amino acids as model compounds for polar and chargeable substances of biochemical and biopharmaceutical interest. Their inherent hydrophilicity requires suitable chromatographic conditions regarding stationary and mobile phase to obtain suitable solubility and peak performance. Ten stationary phases differing in polarity and type of ligands including neutral and charged ones were investigated regarding selectivity, peak performance and complementarity/orthogonality. The mobile phase composition regarding solvent and type of buffer additives by varying the degree of hydrophobicity of the acids and bases and degree of substitution in case of the basic amines. Addition of water to the methanol solvent was furthermore found crucial for obtaining a high peak performance. Some complementary selectivity could be obtained depending on a choice of column. Temperature and pressure variations basically only influenced retention with no selectivity changes. Suitable conditions obtained for the amino acids were then successfully applied to oligo- and polypeptides enabling a separation of 4 polypeptides and differing in only one of the 39 amino acids, thereby mimicking analysis of biotransformation reaction products. The utilization of water as mobile phase additive and sulfonic acids as buffer agents could serve as a generic methodology for polar and charged compounds such as amino containing biomolecules.


Assuntos
Aminoácidos/química , Cromatografia com Fluido Supercrítico/métodos , Peptídeos/isolamento & purificação , Aminas , Interações Hidrofóbicas e Hidrofílicas , Metanol/química , Solventes/química , Ácidos Sulfônicos , Temperatura , Água/química
8.
J Chromatogr A ; 1634: 461703, 2020 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-33234292

RESUMO

The internal energy distributions of thermometer ions dissolved in supercritical and liquid solvents and produced in the gas phase by electrospray (ESI) were measured and compared by the survival yield method. The influence of different chromatographic conditions such as the nature of solvents, the composition of the mobile phase, the pressure of the back pressure regulator was studied for supercritical fluid chromatography (SFC) whereas the influence of the composition and of the flow rate of the mobile phase was investigated for liquid chromatography (LC). The MS instrumental parameters were studied in parallel for SFC and LC showing that the drying gas temperature and the fragmentor voltage affected the internal energy distribution, whereas the capillary voltage did not modify the internal energy distribution. A comparison of the internal energy distributions generated by SFC and LC was carried out leading to conclude that SFC led to higher internal energy, i.e. more in-source fragment ions, than LC.


Assuntos
Técnicas de Química Analítica/métodos , Cromatografia Líquida , Cromatografia com Fluido Supercrítico , Espectrometria de Massas , Técnicas de Química Analítica/normas , Solventes/química
9.
J Chromatogr A ; 1634: 461684, 2020 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-33189960

RESUMO

Supercritical fluid chromatography (SFC), the most common mode of which employs pressurized carbon dioxide as the mobile phase, is enjoying resuscitation. It is once again reconsidered as a fast developing chromatographic technique for the separation and identification of compounds in mixtures. In recent years, significant improvements in instrumentation, and its proficiency in specialized applications, have rekindled interest in the technique. SFC applicability in various fields, such as pharmaceutical analysis, bioanalysis, forensic science, environmental analysis, food science, has continued to expand. The present article delineates a comprehensive up-to-date overview of the applications of SFC in pesticide analysis, including the monitoring of their residues in different matrices and the investigation of their environmental behaviors such as dissipation and bioaccumulation. Since ~30% of currently registered pesticides are chiral compounds, attention is also paid to the analysis of such pesticides due to their enantioselective biological activities. Thus, both achiral and chiral SFC in pesticide analysis is reviewed. The article covers discussions on chromatographic conditions, method validation, and sample preparation as well as comparisons with gas chromatographic and liquid chromatographic approaches.


Assuntos
Técnicas de Química Analítica/métodos , Cromatografia com Fluido Supercrítico , Praguicidas/análise , Dióxido de Carbono/química , Técnicas de Química Analítica/normas , Poluentes Ambientais/análise , Estereoisomerismo
10.
J Chromatogr A ; 1632: 461582, 2020 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-33035852

RESUMO

Selective extraction is a great concern in the field of natural products. The interest is to apply specific conditions favouring the solubility of targeted secondary metabolites and avoiding the simultaneous extraction of unwanted ones. Different ways exist to reach selective extractions with suited conditions. These conditions can be determined from experimental studies through experimental design, but a full experimental design takes time, energy, and uses plant samples. Prediction from varied solubility models can also be applied allowing a better understanding of the final selected conditions and eventually less experiments. The aim of this work was to develop and use a chromatographic model to determine optimal extraction conditions without the need for numerous extraction experiments. This model would be applied on the selective extraction of the desired antioxidant compounds in rosemary leaves (rosmarinic and carnosic acids) vs chlorophyll pigments to limit the green colour in extracts. This model was achieved with Supercritical Fluid Chromatography (SFC) and then applied to Supercritical Fluid Extraction (SFE) and Pressurised Liquid Extraction (PLE) assays. SFC models predicted low solubility of chlorophylls for low (5%) and high (100%) percentage of solvent in carbon dioxide. Also, low solubility was predicted with acetonitrile solvent compared to methanol or ethanol. This was confirmed with different extractions performed using SFE with different percentages of solvent (5, 30, and 70%) and with the three solvents used in the SFC models (acetonitrile, methanol and ethanol). Also extractions using PLE were carried out using the same neat solvents in order to confirm the SFC models obtained for 100% of solvent. Globally, extractions validated the SFC models. Only some differences were observed between ethanol and methanol showing the complexity of plant extraction due to matrix effect. For all these extracts, the content of carnosic acid and rosmarinic acid was also monitored and selective extraction conditions of bioactive compounds could be determined.


Assuntos
Cromatografia com Fluido Supercrítico/métodos , Pressão , Abietanos/análise , Antioxidantes/análise , Dióxido de Carbono/análise , Clorofila/análise , Cinamatos/análise , Depsídeos/análise , Metanol/análise , Extratos Vegetais/química , Folhas de Planta/química , Análise de Regressão , Rosmarinus/química , Solubilidade , Solventes/química
11.
J Chromatogr A ; 1632: 461587, 2020 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-33059177

RESUMO

Supercritical carbon dioxide (scCO2), the main fluid in the mobile phase for supercritical fluid chromatography (SFC), is non-polar. The majority of polar compounds are little soluble in scCO2, thereby rendering them poor candidates for achieving separation by carbon dioxide-based SFC. There is no reported method for the comprehensive analysis of hydrophilic metabolites by SFC with mobile phases comprising a high CO2 ratio. In this study, we investigated the effect of additives in the modifier for enabling the application of SFC to profile diverse polar compounds for metabolomics. Eleven types of columns were screened by using proteinogenic amino acids as the model compounds. The addition of water and acids (formic acid and trifluoroacetic acid (TFA)) to the modifier was also investigated to improve the solubility of the polar compounds and mitigate the unfavorable interaction between the stationary phase and the polar compounds. A significant improvement in the peak shapes of the amino acids was observed upon addition of TFA. The CO2/modifier ratio and TFA concentration in the mobile phases were investigated using the CROWNPAK CR-I (+) column, which showed the best performance during the column-screening. The CO2/methanol/water/TFA ratio of 70/27/3/0.15 (v/v/v/v) was determined as the optimized mobile phase composition. Furthermore, the applicability of the optimized analytical method to other polar compounds was examined; 100 cationic and amphoteric compounds with predicted logPow values that ranged from -5.9 to 1.7 could be simultaneously analyzed without derivatization. Anionic compounds such as organic acids, phosphates, and sugars were excluded from the target analytes. Most of the previously reported SFC methods for analyzing polar compounds employ a gradient elution and require the use of high modifier ratios at 40% or more. In the proposed method, the use of water and TFA enabled the rapid and simultaneous analysis under isocratic elution within 10 min, even with a high CO2 ratio of 70%. Additionally, a rat serum extract was analyzed using the optimized conditions, and 43 polar metabolites were successfully detected. This result demonstrates the applicability of the SFC/tandem mass spectrometry method to real samples.


Assuntos
Cromatografia com Fluido Supercrítico/métodos , Metabolômica/métodos , Espectrometria de Massas em Tandem/métodos , Aminoácidos/análise , Animais , Sangue/metabolismo , Dióxido de Carbono/química , Formiatos/química , Interações Hidrofóbicas e Hidrofílicas , Metanol/química , Ratos , Ácido Trifluoracético/química , Água/química
12.
Mar Pollut Bull ; 159: 111484, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32892919

RESUMO

In this study a novel sustainable method based on supercritical fluid extraction (SFE) method was developed for simultaneous extraction and fractionation of petroleum biomarkers. We herein proposed a two-step supercritical fluid extraction method for crude oil and tar ball to separate the petroleum biomarkers into aliphatic and aromatic fractions. In the first step, pure scCO2 was used, while scCO2 modified was used as a solvent in the subsequent step. CO2 SFE can serve as an environmental-friendly alternative to common column chromatography method for petroleum biomarker or compositional analysis by GC-MS. The extraction process was shown to be selective, according to the polarity of the solvent, providing fractionation of aliphatic and aromatic hydrocarbons. Yet the total extraction procedure in SFE was significantly faster than column chromatography methods (~80 min vs. 8 h). We will discuss the implications of this SFE method as a novel sustainable alternative to the existing extraction techniques.


Assuntos
Cromatografia com Fluido Supercrítico , Petróleo/análise , Biomarcadores , Fracionamento Químico , Cromatografia Gasosa-Espectrometria de Massas
13.
J Chromatogr A ; 1629: 461510, 2020 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-32889298

RESUMO

A two-dimensional system composed of supercritical fluid chromatography (SFC) and reverse phase liquid chromatography (RPLC) coupled a tandem mass spectrometry (MS) was developed for the quantitative analysis of vitamin D in daily oily supplements. Two six-port switching valves are configured, allowing four different valve positions. When the valve positions were fixed at Position A, this system worked at SFC-MS mode. When the valve positions switched between Position B and C, this system worked at a SFC-LC-MS switching mode. Vitamin D3 in two kinds of oily drops, Baby Ddrops and Vitamin AD drops, was determined at both SFC-MS and SFC-LC-MS switching modes by using the same system. The linearity, repeatability and recovery were investigated using the internal and external standard methods for the two modes. The results obtained from the internal standard method are better than those of the external standard method at either mode. The coefficient of determination (r2) for the internal standard method is more than 0.999, with a linear range of 20-1000 µg/L. Both Baby Ddrops and Vitamin AD drops were analyzed with good repeatability (<3.21%) and recovery (94.1%-116.1%) using internal standard method. When calculated by the external standard method, as compared to SFC-MS mode, SFC-LC-MS switching mode has better linearity (r2>0.999), repeatability (Baby Ddrops: 4.45%, Vitamin AD drops: 1.12%) and recovery (86.3%-107.1%). The results indicate that the two-dimensional SFC-MS/SFC-LC-MS system is useful for determination of vitamin D in oily drops. If it works at SFC-MS mode, the internal standard is required. When SFC-LC-MS switching mode is used, external standard method can also obtain the accurate results with good precision.


Assuntos
Colecalciferol/análise , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia com Fluido Supercrítico/métodos , Suplementos Nutricionais/análise , Colecalciferol/isolamento & purificação , Cromatografia de Fase Reversa , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem/métodos
14.
Chemosphere ; 260: 127639, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32758767

RESUMO

Lipids are biomolecules extracted from plant sources and plant residues and have a beneficial role in various food, nutrition and medical applications. Supercritical carbon-dioxide as an advanced high-pressure technology which increases the productivity and has negligible environmental impact is employed for the selective extraction of polar lipids from the lipid matrix in mango kernel for the first time. The process parameters affecting the extraction such as pressure, temperature and the flow rate of CO2 are ranged in the intervals of 30-50 MPa, 40-60 °C and 10-30 g min-1, respectively. Optimization using Box Behnken design obtained the highest yield of 3.38% at 40 °C, 50 MPa and 30 g min-1. The phosphorous content was evaluated to understand the behaviour of polar lipids extraction at higher pressures. The study showed the effect of process parameters having significant influence on polarity and solvating capacity of CO2 which enabled for the extraction of polar lipids adding value to the mango kernel converting waste into valuable industrial products. The economic evaluation estimates the return on investment of a plant processing 3000 tons of mango kernel per year to account net present value (NPV) almost five times higher than the investment expenses and the payback period is under 4 years.


Assuntos
Dióxido de Carbono/química , Fósforo/química , Cromatografia com Fluido Supercrítico , Análise Custo-Benefício , Lipídeos/química , Mangifera , Extratos Vegetais/química , Temperatura
15.
J Chromatogr A ; 1626: 461352, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797832

RESUMO

In the present study, we characterize a famous Pirkle-type enantioselective stationary phase ((R,R)-Whelk-O1 from Regis Technologies) and an equivalent enantiomeric phase (ReproSil Chiral-NR from Dr. Maisch) in supercritical fluid chromatography (SFC) with carbon dioxide - methanol (90:10 v/v) mobile phase. First, the interactions contributing to retention are evaluated with a modified version of the solvation parameter model, comprising five Abraham descriptors (E, S, A, B, V), two additional descriptors to take account of molecular shape (flexibility F and globularity G), and two additional descriptors to take account of interactions with ionizable species (D- and D+). Linear solvation energy relationships (LSER) are established based on the retention of 212 achiral analytes. As expected, π-π interactions are the most significant to explain retention, while dipole-dipole, hydrogen bonding and ionic interactions with cationic species are of secondary importance. Secondly, the contributions of interactions to enantioseparations are discussed, based on the analysis of 79 racemates. Discriminant analyses (DA) were computed to gain some insight on retention mechanisms. The set of racemates is first divided between racemates eluted earlier than expected based on the LSER models, and those eluted later than expected. Small spherical molecules are more retained than expected, as they may better fit inside the cleft of the chiral selector. They are also most frequently resolved, probably for the same reason. Among the molecules that are less retained than expected, which are rather large and/or non-spherical, other features are favourable to enantiorecognition: π-electrons, dipoles and electron-donating properties. Contrary to the observations on other sorts of chiral selectors, flexibility was found to have no contribution on the enantiorecognition process.


Assuntos
Cromatografia com Fluido Supercrítico/métodos , Dióxido de Carbono/química , Análise Discriminante , Ligação de Hidrogênio , Íons , Metanol/química , Modelos Teóricos , Estereoisomerismo
16.
J Chromatogr A ; 1626: 461320, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797816

RESUMO

BMS-986142 is a Bruton's tyrosine kinase inhibitor under development to treat several disease types. The compound contains three chiral elements: one chiral center and two chiral axes, resulting in three potential atropisomeric impurities in its drug substance and drug products. Separation of BMS-986142 atropisomers has been successfully achieved on an achiral polar-embedded C18 column in reversed-phase liquid chromatography (RPLC) and on polysaccharide-based chiral columns in RPLC and supercritical fluid chromatography (SFC). Compared to the RPLC chiral separation, the SFC atropisomeric separation on a sub-2 µm immobilized cellulose-based column is much more efficient and environmentally friendly. The analysis time in SFC was reduced by 8-fold compared to that in RPLC, and the method sensitivity in SFC on the sub-2 µm chiral column in 3.0 mm I.D. was 2 to 4-fold better than that on 3 µm chiral columns in 4.6 mm I.D.. Furthermore, our study suggests that the contribution to band broadening from the extra column volume (ECV) of modern commercial SFC instrument was not negligible for a 3.0 mm I.D. × 100 mm column packed with 1.6 µm particles. This result reaffirms that there is a great need for further improvement of SFC instrument design in order to realize the full theoretical efficiency of both sub-2 µm achiral and chiral columns.


Assuntos
Cromatografia com Fluido Supercrítico/métodos , Polissacarídeos/química , Inibidores de Proteínas Quinases/análise , Cromatografia de Fase Reversa , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/isolamento & purificação , Estereoisomerismo
17.
J Chromatogr A ; 1626: 461363, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797842

RESUMO

Analytical techniques to determine volatile compounds such as flavor, aroma, and fragrances are in high demand due to their wide range of applications in industry, the chemical properties of them are very diverse. Supercritical fluid chromatography (SFC) is capable of high speed, high peak capacity separation and has a high separation coverage. It is also an advantageous for preparative purifications due to its unique mobile phase conditions. However, there is no column commercially available for SFC that is suitable to comprehensively separate volatile compounds. SFC is limited to the use of silica-based columns due to weak retentions and polymer-based column issues such as pressure, swelling and shrinkage tolerances. This study demonstrated comprehensive analytical method for volatile in SFC using a highly cross-linked styrene divinylbenzene (SDVB) polymer-based column, newly developed for SFC. In this study, 23 typical volatile compounds with a wide variety of chemical properties were selected as model compounds. The newly developed SDVB column showed, compared to conventional silica-based columns (k > 0.3), an excellent overall and substantial improved retentions (k > 1.6) under SFC mobile phase conditions. It was also able to retain esters (hydroxy acetate, pentyl butylate, methyl salicylate) and non-polar terpenes (limonene, pinene) that did not show sufficient retention in any other commercially available silica-based columns. Aldehydes reacting on NH2 column due to Schiff base formation were also successfully eluted. It was confirmed that SDVB column provided comprehensive separation and wide coverage for volatile compounds.


Assuntos
Cromatografia com Fluido Supercrítico/métodos , Poliestirenos/química , Compostos de Vinila/química , Espectrometria de Massas , Dióxido de Silício , Terpenos/isolamento & purificação , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/isolamento & purificação
18.
J Chromatogr A ; 1625: 461257, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32709317

RESUMO

Fixed dose combination (FDC) of tenofovir disoproxil fumarate (TDF) and lamivudine (3TC) is one of the most preferred FDC for the treatment of acquired immunodeficiency syndrome (AIDS)/human immunodeficiency virus (HIV) infection. To the best of authors' knowledge there are no reported methods for chiral purity estimation of both drugs simultaneously from a FDC. The current study was focused on the development of a single chiral method uisng supercritical fluid chromatography (SFC) for separation of stereoisomers of TDF and 3TC combination employing design of experiment (DoE) approach. Method development was planned in three steps by using different experimental designs for each step. I-optimal, Taguchi orthogonal array and face-centred central composite designs (CCD) were employed for primary parameter selection, secondary parameter screening and final method optimization, respectively. All six stereoisomers were separated in a 10 minute run on Chiralpak IA column with carbon di-oxide /methanol (containing 0.5 % v/v n-butylamine) as mobile phase at 1.5 mL/min in gradient mode. The optimized method was verified for performance through establishing specificity, precision, linearity, accuracy, limit of quantification, and solution stability. Resolution between each isomeric pair was more than 1.5. The method was found to be linear from 1.5 µg/mL to 7.5 µg/mL for 3TC and 7.5 µg/mL to 37.5 µg/mL for TDF stereoisomers. The R2 values for all the linearity curves for undesired isomers were greater than 0.995. The method proved to be rapid, reproducible and efficient to quantify stereoisomers of both drugs in a single run.


Assuntos
Cromatografia com Fluido Supercrítico/métodos , Lamivudina/análise , Tenofovir/análise , Lamivudina/química , Padrões de Referência , Reprodutibilidade dos Testes , Estereoisomerismo , Tenofovir/química
19.
J Chromatogr A ; 1625: 461286, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32709336

RESUMO

In the past two decades, supercritical fluid chromatography has evolved from a niche application to a comprehensive technology and a fully-fledged alternative to conventional high-performance liquid chromatography. In this study, we have focused on chiral separation of synthetic cathinones in gradient supercritical fluid chromatography coupled to mass spectrometry using an inverse gradient of a make-up solvent. Synthetic cathinones possess an amphetamine-like effect and, therefore, are frequently being offered on the Internet as a replacement for illicit drugs. Cathinones are chiral compounds, however, they are usually marketed and used as racemic mixtures. Since the effect of individual enantiomers can significantly vary, there is a need for the development of enantioseparation methods enabling to study the biological effects of individual enantiomers. Since cathinones are basic molecules, they are easily protonated (positively charged) under weakly acidic mobile phase conditions, which is a typical feature of supercritical mobile phases with an alcohol as an organic modifier. The positively charged species represent ideal analytes for ion exchangers, such as chiral zwitterion ion exchangers Chiralpak ZWIX (+) and Chiralpak ZWIX (-), which possess a positively and negatively charged unit in the molecular structure of the selectors. The presence of the positive charge in the selector's structure, functioning as a counter-ion for the positively charged analytes, significantly reduces the required amount of a buffer, which is plausible for hyphenation of such a separation system with mass spectrometry. For mass spectrometry hyphenated to supercritical fluid chromatography, the use of a make-up solvent is required to avoid analyte precipitation when using a low concentration of an organic co-solvent (modifier) in the super-/subcritical mobile phase. Hereby, we introduce a unique approach, which is based on the gradient introduction of the make-up to the post-column effluent. Using this approach, it is possible to keep constant the overall amount of the organic solvent (modifier and make-up) introduced into the mass spectrometer when using a gradient of the organic modifier. We show that the developed gradient elution method facilitates the chiral separation of all employed analytes, while the mobile-phase gradient compensation by the inverse make-up gradient enables their detection with high signal intensities.


Assuntos
Alcaloides/química , Alcaloides/isolamento & purificação , Cromatografia com Fluido Supercrítico/métodos , Espectrometria de Massas/métodos , Reologia , Solventes/química , Alcaloides/síntese química , Cromatografia Líquida de Alta Pressão , Pressão , Estereoisomerismo , Temperatura
20.
J Chromatogr A ; 1625: 461299, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32709342

RESUMO

The work describes a novel supercritical fluid chromatography method for the separation of four stereoisomers, RZ(+), SZ(-), RE(+) and SE(-) of luliconazole, an antifungal agent on amylose tris[(S)-α-methylbenzyl carbamate] based Chiralpak IH column. The effect of organic modifiers (methanol, ethanol and isopropanol), column temperature and back pressure were evaluated for their selective separation. A consistent elution order, RZ(+) > SZ(-) > RE(+) > SE(-) was observed in all the modifiers. Amongst the three modifiers, the best result in terms of selectivity, resolution and analysis time was obtained with isopropanol. Analytical separation (Rs > 1.5) of RZ(+) and SZ(-) & RE(+) and SE(-) pairs was achieved with a mobile phase consisting of CO2: isopropanol (80: 20, v/v) within 5.0 min. The retention of isomers increased with increase in temperature and decreased with increase in pressure, which was more prominent for RE(+) and SE(-) isomers. The van't Hoff plots revealed that the chiral separation process was essentially entropy driven. Molecular docking was performed to understand the type of chiral recognition between the stereoisomers and the chiral stationary phase and to understand their elution orders under optimized conditions. The results suggested hydrogen bonding and π-π interactions, as the dominant interaction modes. The elution order and binding energy of the interactions were in good agreement with the experimental results. Quantitative studies of RE(+) luliconazole the pharmacologically active isomer was also performed using a marketed formulation.


Assuntos
Cromatografia com Fluido Supercrítico/métodos , Imidazóis/química , Imidazóis/isolamento & purificação , Simulação de Acoplamento Molecular , Entropia , Ligação de Hidrogênio , Fenilcarbamatos/química , Pressão , Reprodutibilidade dos Testes , Estereoisomerismo , Termodinâmica
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