Supercritical Fluid Chromatography

Food, drugs, dyes, extracts, and minerals are all made up of complex elements, and utilizing unidimensional chromatography to separate them is inefficient and insensitive. This has sparked the invention of several linked chromatography methods, each of them with distinct separation principles and affinity for the analyte of interest. Multidimensional chromatography consists of the combination of multiple chromatography techniques, with great benefits at the level of efficiency, peak capacity, precision, and accuracy of the analysis, while reducing the time required for the analysis. Various coupled chromatography techniques have recently emerged, including liquid chromatography–gas chromatography (LC–GC), gas chromatography–gas chromatography (GC–GC), liquid chromatography–liquid chromatography (LC–LC), GCMS–MS, LCMS–MS, supercritical fluid techniques with chromatography techniques, and electro-driven multidimensional separation techniques. In this paper, the different coupled chrom...

The retention process in supercritical fluid chromatography depends on the solute volatility as well as the strength of the mobile phase. When the capacity factor is plotted as a function of temperature at constant pressure, the curve passes through a maximum point. At higher temperatures, the capacity factor decreases as the temperature increases, and at lower temperatures the opposite is observed. This makes prediction of the capacity factor in supercritical fluid chromatography complicated. Rigorous thermodynamic equations to predict retention characteristics result in complex equations. A simple empirical approach for prediction of the capacity factor as a function of mobile phase density and column temperature is presented.

The retention process in supercritical fluid chromatography depends on the solute volatility as well as the strength of the mobile phase. When the capacity factor is plotted as a function of temperature at constant pressure, the curve passes through a maximum point. At higher temperatures, the capacity factor decreases as the temperature increases, and at lower temperatures the opposite is observed. This makes prediction of the capacity factor in supercritical fluid chromatography complicated. Rigorous thermodynamic equations to predict retention characteristics result in complex equations. A simple empirical approach for prediction of the capacity factor as a function of mobile phase density and column temperature is presented.

In SFC the sample cannot be dissolved in the mobile phase, so it is often dissolved in pure modifier, or another liquid, sometimes resulting in serious distortions of the eluted peak profiles already at moderately high injection volumes. It is suspected the reasons for these effects are solvent strength mismatch and/or viscosity mismatch. This study presents a systematic and fundamental investigation of the origin of these peak deformations due to the injection solvent effects in SFC, using both systematic experiments and numerical modeling. The first set of experiments proved that the injection volume and the elution strength of the sample solution had a major impact of the shapes of the eluted peaks. Secondly, the sample band elution profile was numerically modeled on a theoretical basis assuming both un-retained and retained co-solvent injection plugs, respectively. These calculations quantitatively confirmed our first set of experiments but also pointed out that there is also an additional significant effect. Third, viscous fingering experiments were performed using viscosity contrast conditions imitating those encountered in SFC. These experiments clearly proved that viscous fingering effects play a significant role. A new method for determination of adsorption isotherms of solvents was also developed, called the "Retention Time Peak Method" (RTPM). The RTPM was used for fast estimation of the adsorption isotherms of the modifier and required using only two experiments.

Supercritical fluid technology is a process using a supercritical fluid as a solvent. When a fluid is taken above its critical temperature (Tc) and critical pressure (Pc), it exists in a condition called the supercritical fluid state. The physico-chemical properties of a fluid in the supercritical state are in between those of a typical gas and liquid. Due to increasingly stringent environmental regulations, supercritical fluid technology (SFT) has gained wide acceptance in recent years as an alternative to conventional solvent extraction for herbal compounds as well as in many analytical and industrial processes. This article presents the practical aspects of SFT applications in selection of modifiers, on-line offline coupling techniques. SFT can also be used to clean up pesticides from herbal medicines. Carbon dioxide is most commonly used Supercritical Fluid (SF) as it is safe, inexpensive, non-toxic, non-inflammable and inert to most of the materials as well as its solvating str...

The present study describes a reversed phase ultra performance liquid chromatographic (RP-UPLC) method development and validation for dertermination of Itraconazole in capsule formulation. Accquity BEH C18 column was used as stationary phase while mobile phase A was buffer: Tetrahydrofuran, 95:05 v/v (Buffer=0.1%v/v Triethylamine in water pH 2.5 by orthophospheric acid) and mobile phase B as Acetonitrile. Method was developed in isocratic binary mode with 8 minutes run time, at flow rate of 0.40 mL/min. Eluent was monitored at 260nm. The developed method separates Itracoazole from its seven related compounds by 8 minutes run time. Stability indicating capability of developed method is established by analysing forced degradation samples in which spectral purity of Itraconazole ascertained along with separation of degradation products from analytes peak. The method was validated for specificity, linearity, accuracy, precision, robustness and solution stability. Recovery was found to b...

A non-uorescent pigment produced from the uorescent Bacillus endophyticus AVP-9 which possess abundant lutein content considered as a xanthophyl-type compound with potentially bene cial pharmacological properties for enhancing human health. In this context, bacterial lutein was extracted by employing different solvents to isolate from Bacillus endophyticus was examined in this study. Chromatographically puri ed lutein was spectrally characterized using ultraviolet-visible spectrometry and spectral analysis was carried through liquid chromatography-mass spectrometry, functional group identi cation was done by using fourier transform-infrared spectroscopy, structural determination by nuclear magnetic resonance spectrometry. By using hexane and ethyl acetate (7:3) with the ow rate of 5ml/min, was proven to be an excellent solvent phase for separation of lutein, meaning that up to 90% pure lutein generated with a 60% estimated yield. The puri ed compound identi ed as a β, ε-3, 3 1 -diol (lutein) having molecular weight of 568.6g/mol with the molecular formula C 40 H 56 O 2 which exhibits potential antibacterial activity against E. coli (35mm) followed by S. typhi (33mm), S. exneri (30mm), P. aureginosa (29mm), M. lutea (28mm), P. vulgaris (24mm), S. aureus (21mm) and lowest antibacterial activity against V. cholera (19mm). Puri ed pigment shows concentration dependent antioxidant activities with IC 50 values of pigment was found to be 4.5 mg/ml. Whereas anti-proliferation activity pigment shows considerable effect MCF-7 and LNCaP cell lines, when treated with 100µg/ml, cell viability was decreased to 36.363% at IC 50 value of 21.935 µg/ml and for LNCaP, the cell viability was decreased to 42.449% at IC 50 value of 56.937 µg/ml.

A new Supercritical fluid liquid chromatographic (SFC) method has been developed in normal-phase conditions for the determination of enantiomeric purity of Montelukast sodium (S,E)-2-(1-((1-3-(2-(7-chloroquinolin-2-yl)vinyl)phenyl)-3-(2-(2hydroxypropan-2-yl)phenyl)propylthio)ethyl) cyclopropyl) acetic acid (R-isomer) (Anti asthmatic drug) in bulk drugs and in dosage forms. The sample was screened on the analytical SFC to determine the best column for the separation. The screening conditions are Column: Chiralpak AS-H (250 mm x 4.6 mm, 5 μm) column using a mobile phase system containing Supercritical fluid (Co2) and 2-Propanol in the ratio (85:15% v/v). The mobile-phase compositions and the differences in separation capability of the method is noted. The resolution between two enantiomers is found to be greater than 1.5. The SFC method for the separation of enantiomers of Montelukast is proved Accurate, Precise, Linear and robust. Relative standard deviation of retention times and peak areas were better than 0.2% and 0.4%, respectively, for precision.

A new Supercritical fluid liquid chromatographic (SFC) method has been developed in normal-phase conditions for the determination of enantiomeric purity of Montelukast sodium (S,E)-2-(1-((1-3-(2-(7-chloroquinolin-2-yl)vinyl)phenyl)-3-(2-(2-hydroxypropan-2-yl)phenyl)propylthio)ethyl) cyclopropyl) acetic acid (R-isomer) (Anti asthmatic drug) in bulk drugs and in dosage forms. The sample was screened on the analytical SFC to determine the best column for the separation. The screening conditions are Column: Chiralpak AS-H (250 mm x 4.6 mm, 5 μm) column using a mobile phase system containing Supercritical fluid (Co2) and 2-Propanol in the ratio (85:15% v/v). The mobile-phase compositions and the differences in separation capability of the method is noted. The resolution between two enantiomers is found to be greater than 1.5. The SFC method for the separation of enantiomers of Montelukast is proved Accurate, Precise, Linear and robust. Relative standard deviation of retention times and p...

Chlorophyll extraction plays a pivotal role in enhancing the functional properties of microalgal biomass for biofuel applications. This study investigated the efficiency of four commonly used solvents-methanol, ethanol, acetone, and diethyl ether in extracting chlorophyll from Chlorella vulgaris and Scenedesmus quadricauda under different experimental conditions. Extractions were conducted at three temperatures (20 °C, 40 °C, and 60 °C) and two-time intervals (5 and 10 minutes). Extraction efficiency was evaluated using the Extraction Efficiency Index, Temperature Sensitivity Index, Time Efficiency Index, Coefficient of Variation, and Comprehensive Extraction Index. Statistical analyses, including ANOVA and post-hoc tests, were conducted to identify significant differences at p≤0.05 among solvents and microalgae species. Methanol proved to be the most effective solvent for extracting chlorophyll. The highest chlorophyll concentrations were observed at 60 °C after 10 minutes, reached 21mg/L for C. vulgaris and 19.4 mg/L for S. quadricauda. Statistical analysis revealed significant differences (p<0.001) in chlorophyll extraction among the solvents, with methanol recorded as the best solvent. The EEI for methanol was 79.68% for C. vulgaris and 79.23% for S. quadricauda, indicating the highest extraction performance. Temperature significantly influenced extraction efficiency, with the highest yield at 60 °C. TEI and TSI confirmed that methanol had the highest extraction performance. Post-hoc analysis confirmed significant differences between methanol and other solvents.

The technical report "Analytical method and characterization of fatty acids from marine foods matrices: property and recent trend" is part of the project "Sperimentazione e validazione di nuove tecnologie per il miglioramento della shelflife dei prodotti ittici attraverso l'uso di un film edibile a base pectinica"-PECTINE-PON Research and Competitiveness 2007-2013. The aim was to test and validate a mixture based pectinic able to lengthen the shelf life of fish products, through the study and analysis of the mixture in toto for the evaluation of its eco-toxicity and the analysis of useful indicators (polyunsatured fatty acids, biogenic amines, proteolysis, pattern of protein, etc.) to estimate the deterioration of the products. The different assays predicted also analysis of indicators to evaluate the nutritional parameters, in particular the qualitative and quantitative analysis fatty acids (Masullo et al., 2015 a; Masullo et al., 2015 b).

This revision presents applications of multivariate curve resolution alternating least squares (MCR-ALS) applied to chromatographic data. Initially, the fundamentals and recent advances of the MCR-ALS method will be presented. Several critical issues such as data organization, advantages of the modelling, constraints, evaluation of ambiguity and the use for mathematical separation is discussed. An extensive revision of the papers on MCR-ALS applied to chromatographic data reported up to 2020 is presented. A practical example of an innovative application of cholesterol lowering drugs using supercritical fluid chromatography (SFC) is described highlighting important aspects of the method. At the end, a list of links to MCR-ALS algorithms and graphical interfaces developed in Matlab, R and Python 3 is provided.

Glycerolysis of soybean oil was conducted in a supercritical carbon dioxide (SC-CO?) atmosphere to produce monoglycerides (MG) in a stirred autoclave at 150-250°C, over a pressure range of 20.7-62.1 MPa, at glycerol/oil molar ratios between 15-25, and water concentrations of 0-8% (wt% of glycerol). MG, di-, triglyceride, and free fatty acid (FFA) composition of the reaction mixture as a function of time was analyzed by supercritical fluid chromatography. Glycerolysis did not occur at 150°C but proceeded to a limited extent at 200°C within 4 h reaction time; however, it did proceed rapidly at 250°C. At 250°C, MG formation decreased significantly (P < 0.05) with pressure and increased with glycerol/oil ratio and water concentration. A maximum MG content of 49.2% was achieved at 250°C, 20.7 MPa, a glycerol/oil ratio of 25 and 4% water after 4 h. These conditions also resulted in the formation of 14% FFA. Conversions of other oils (peanut, corn, canola, and cottonseed) were also attempted. Soybean and cottonseed oil yielded the highest and lowest conversion to MG, respectively. Conducting this industrially important reaction in SC-CO) atmosphere offered numerous advantages, compared to conventional alkalicatalyzed glycerolysis, including elimination of the alkali catalyst, production of a lighter color and less odor, and ease of separation of the CO 2 from the reaction products.

Packed-coiumn supercritical fluid chromatography with flame ionization detection (SFC-FID) has been appiied to the analysis of abused vegetable oiis. Previous studies have shown that packed-column SFi=-FID of poiar solutes is difficult due to the unshielded surface siianols on SFC stationary phases. The use of a polymeric resin-based stationary phase or high-temperature water saturation with a bonded-silica column eliminates the probiem. With the use of the polymeric resin-packed column. silanophiiic interactions are non-existent. High-temperature water saturation of the carbon dioxide mobile phase provides water as a modifier at levels of 2 to 3 mole%. levels previously unattained in packed-column SFC. At this concentration, water notably minimizes fatty acid interactions with the bonded-siiica column. yet allows the use of FID. These two chromatographic approaches are illustrated on lipid-containing samples such as oil from storage-abused soybeans and a commercial frying fat. Chromatograms obtained by packedcolumn SFC-FID are compared with separations attained using capillary-column SFC. Packed-microbore SFC-FID results show a linear correlation with free fatty acid content determined by ;I standard titration method. ' The mention of tirm names or trade products does not Imply that they are cndorscd or recommended by the United States Department of Ggricuiture over other firms or similar products not mentioned.

In this work, we have studied both experimentally and theoretically the praziquantel (PZQ) chiral discrimination. According to the main results, the enantioseparation of PZQ was efficiently optimized by HPLC on the reverse phase from the Chiralpak IB column, which has cellulose tris (3,5dimethylphenylcarbamate) (CDMPC) as a chiral selector. The thermodynamic and structural parameters obtained via density functional theory (DFT) calculations pointed out the chiral discrimination as well as the enantiomeric elution order of PZQ, thus elucidating the experimental data and validating our proposed method. Finally, the hydrogen bonds and π-π stacking interactions played a key role in the discrimination between the PZQ diastereomeric complexes formed.

The synthesis of a polysiloxane containing chemically bonded chiral metal complex derived from nickel(I1) bis[(3-heptafluorobutanoyl)-lo-methylene-( lR)-camphorate] (ChirasiI-nickel) and its effective immobilization on the inner surface of fused-silica capillaries by thermal treatment is described. As expected, the immobilization properties were found to be dependent on the content of residual reactive Si-R groups in the polymer backbone (R = OCH,, H). The immobilized Chirasil-nickel stationary phase was employed for the analytical enantiomer separation of coordinating solutes by high-resolution capillary gas and supercritical fluid chromatography. The increase in the relative retention monitored for racemic test solutes after rinsing the columns indicates a slight increase in the effective complex concentration which does not affect the chiral separation factor a. The temperature limit of analysis was raised to 170-180°C for temperature-programmed runs and to 140-150°C under isothermal conditions, thus extending the scope of complexation gas chromatography considerably, as demonstrated by various enantiomer separations performed at elevated temperatures. When Chirasil-nickel is immobilized on the inner surface of short, narrow-bore capillaries (50 pm I.D.), it can be employed in complexation supercritical fluid chromatography, combining the high solvation strength of supercritical carbon dioxide with the benefit of low operating temperatures, enhancing enantioselectivity. INTRODUCIION * Corresponding author. food additives) [l-3]. It is now well appreciated that the separation of enantiomers on chiral, non-racemic stationary phases by capillary chromatography represents a powerful tool for quantitative enantiomer analyses because of the high resolution, speed and sensitivity. Chiral recognition in chromatography may arise from various types of enantioselective interactions between the solute (selectand) and the chiral, non-racemic moiety (selector), e.g., hydrogen bonding [4], charge transfer [5], dipoledipole [6], inclusion [7,8] and combinations thereof [9]. Complexation chromatography offers a valuable complementary method based on coordination as the formation of the diastereo-

The synthesis of a polysiloxane containing chemically bonded chiral metal complex derived from nickel(I1) bis[(3-heptafluorobutanoyl)-lo-methylene-( lR)-camphorate] (ChirasiI-nickel) and its effective immobilization on the inner surface of fused-silica capillaries by thermal treatment is described. As expected, the immobilization properties were found to be dependent on the content of residual reactive Si-R groups in the polymer backbone (R = OCH,, H). The immobilized Chirasil-nickel stationary phase was employed for the analytical enantiomer separation of coordinating solutes by high-resolution capillary gas and supercritical fluid chromatography. The increase in the relative retention monitored for racemic test solutes after rinsing the columns indicates a slight increase in the effective complex concentration which does not affect the chiral separation factor a. The temperature limit of analysis was raised to 170-180°C for temperature-programmed runs and to 140-150°C under isothermal conditions, thus extending the scope of complexation gas chromatography considerably, as demonstrated by various enantiomer separations performed at elevated temperatures. When Chirasil-nickel is immobilized on the inner surface of short, narrow-bore capillaries (50 pm I.D.), it can be employed in complexation supercritical fluid chromatography, combining the high solvation strength of supercritical carbon dioxide with the benefit of low operating temperatures, enhancing enantioselectivity. INTRODUCIION * Corresponding author. food additives) [l-3]. It is now well appreciated that the separation of enantiomers on chiral, non-racemic stationary phases by capillary chromatography represents a powerful tool for quantitative enantiomer analyses because of the high resolution, speed and sensitivity. Chiral recognition in chromatography may arise from various types of enantioselective interactions between the solute (selectand) and the chiral, non-racemic moiety (selector), e.g., hydrogen bonding [4], charge transfer [5], dipoledipole [6], inclusion [7,8] and combinations thereof [9]. Complexation chromatography offers a valuable complementary method based on coordination as the formation of the diastereo-

The immobilized polysaccharide-derived chiral stationary phases (CSPs) combine the benefits of broad application scope and high preparative potential with CSP robustness and universal solvent compatibility. Strategies for efficient and straightforward method development with these CSPs were previously overviewed. In the current study, six CSPs with different structural features in the immobilized series were examined for their complementary properties in separation of enantiomers. Some method development aspects related to polysaccharide-derived CSPs in general and certain specific features observed on these immobilized supports, such as the effects of mobile phase, sample solvent and mobile phase additive on chiral separation, are also discussed.

Carotenoids are isoprenoids widely distributed in foods that have been always part of the diet of humans. Unlike the other so-called food bioactives, some carotenoids can be converted into retinoids exhibiting vitamin A activity, which is essential for humans. Furthermore, they are much more versatile as they are relevant in foods not only as sources of vitamin A, but also as natural pigments, antioxidants, and health-promoting compounds. Lately, they are also attracting interest in the context of nutricosmetics, as they have been shown to provide cosmetic benefits when ingested in appropriate amounts. In this work, resulting from the collaborative work of participants of the COST Action European network to advance carotenoid research and applications in agrofood and health (EUROCAROTEN, www.eurocaroten.eu, tabsjName:overview) research on carotenoids in foods and feeds is thoroughly reviewed covering aspects such as analysis, carotenoid food sources, carotenoid databases, effect of processing and storage conditions, new trends in carotenoid extraction, daily intakes, use as human, and feed additives are addressed. Furthermore, classical and recent patents regarding the obtaining and formulation of carotenoids for several purposes are pinpointed and briefly discussed. Lastly, emerging research lines as well as research needs are highlighted.

Satureja thymbra L. is well known in Italy by the popular name of “Santoreggia sarda”. It grows only in Sardinia and nowadays it is restricted to the slope of the Colle San Michele in Cagliari. The composition of the aromatic extracts obtained by supercritical CO2 and by hydrodistillation and their antifungal activity is reported. The collected extracts were analyzed by GC-FID and GC-MS methods. No significant differences were observed in the composition of the volatile extracts depending on the extraction method. The results showed the presence of thymol, γ-terpinene, β-caryophyllene, p-cymene, carvacrol and borneol as main components. The minimal inhibitory concentration (MIC) and the minimal lethal concentration (MLC) were used to evaluate the antifungal activity of the oils against Candida albicans, C. tropicalis, C. krusei, C. guillermondii, C. parapsilosis, Cryptococcus neoformans, Trichophyton rubrum, T. mentagrophytes, T. mentagrophytes var. interdigitale, Trichophyton rubru...

The volatiles from Coriandrum sativum L., Satureja montana L., Santolina chamaecyparissus L., and Thymus vulgaris L. were isolated by hydrodistillation (essential oil) and supercritical fluid extraction (volatile oil). Their effect on seed germination and root and shoot growth of the surviving seedlings of four crops (Zea mays L., Triticum durum L., Pisum sativum L., and Lactuca sativa L.) and two weeds (Portulaca oleracea L. and Vicia sativa L.) was investigated and compared with those of two synthetic herbicides, Agrocide and Prowl. The volatile oils of thyme and cotton lavender seemed to be promising alternatives to the synthetic herbicides because they were the least injurious to the crop species. The essential oil of winter savory, on the other hand, affected both crop and weeds and can be appropriate for uncultivated fields.

The supercritical fluid technology has been target of many pharmaceuticals investigations in particles production for almost 35 years. This is due to the great advantages it offers over others technologies currently used for the same purpose. A brief history is presented, as well the classification of supercritical technology based on the role that the supercritical fluid (carbon dioxide) performs in the process. Key words: Supercritical fluid technology, supercritical carbon dioxide, pharmaceuticals.

Several test compounds were introduced into a unidirectional flow Ion mobillty spectrometer by both gas chromatography (GC) and supercritical fluld chromatography (SFC). The test samples were drugs from three general classes, opiates, benrodiazoplnones, and steroids. Drm spectra were collected for each compound by Fourier transform ion moblllty spectrometry. The drlft veioclty data for each compound was corrected for temperature and pressure dlfferences by conversion to reduced mobllity values, K,. Agreement of KO values for each method confkmed that the mobility of product ions In the unldirectlonai flow ion mobility spectrometer is independent of the introduction method. I n addition, drift tknes of the reactant ions In the spectrometer were compared for conditions of the presence of a contaminating CO, flow and the absence of any CO, flow. I t was found that there were no differences In the mobliitles of the reactant ions caused by CO, contamination, Indicating that the identities of the reactant ions were not affected by CO, flow.

High Temperature Capillary GC and Capillary SFC have been applied to the analysis of non‐ionic lubricants, i.e. alkylphenol polyethoxylates (APnEO), ethoxylated alcohols (nEOAIc), polyethylene glycols (PEG), and ethoxylated triethanolamines (nEOEA); to the analysis of anionic lubricants, i.e. alkylbenzene‐sulfonates (ABS), alkylsulfonates (AS), and ethoxylated phosphoric acids (nEOPhA); and to the analysis of cationic lubricants, i.e. quaternary ammonium salts (Quats). Both techniques are compared in terms of resolution and analysis time. The importance of derivatization in HT‐CGC and CSFC is illustrated.

Antioxidants from orange juice are isolated by the use of countercurrent supercritical fluid extraction (CC-SFE) and characterized by reversed-phase liquid chromatography (RPLC) coupled to mass spectrometry (MS) and diode-array detection (DAD). A pilot-scale SFE plant equipped with a packed column has been employed for countercurrent extraction and fractionation of raw orange juice with carbon dioxide. Several experiments have been performed in order to study the effect of the countercurrent conditions on the content of antioxidative compounds. In this study, the main variable that has been considered is the solvent-to-feed ratio (S/F) because it plays an essential role in the extraction efficiency. The values tested covered a wide range of sample and solvent (CO 2 ) flow rates. In each experimental run, two different extracted fractions and the residual nonextracted juice were obtained and characterized. Different flavonoids have been identified in the fractions obtained after CC-SFE. The possibility of using this process for antioxidant compounds enrichment is discussed.

Screen technology for "smart" devices continues to advance as researches seek to enhance display performance by reducing energy consumption and improving color characteristics. To that end, researchers are turning to organic light-emitting diodes (OLEDs) as the display materials due to higher energy saving and richer color compared to liquid crystal displays (LCDs). However, one major setback of the OLED technology is that the devices are very sensitive to the impurities present in the OLED materials, impacting device lifetime, stability, and overall performance. The isolation of large quantities of the main OLED components from the synthetic impurities is challenging using the traditional purification process (i.e., train sublimation), which has poor reproducibility, and high capital and operating cost. Supercritical fluid chromatography (SFC) could lend itself as an alternative technique for the profiling of impurities and their purification. In this study, we investigated the use of SFC to analyze a mixture of amorphous monomeric molecular glasses with charge-transporting property typical of OLED materials. The separation behavior of four different chromatographic columns containing the stationary phases 1aminoanthracene (1-AA), naphthyl, 2-ethylpyridine, and C-18 were examined to perform the SFC separations. The effect of using three different co-solvents (i.e., isopropyl alcohol, acetonitrile, and tetrahydrofuran) to the CO2 mobile phase on the separation selectivity and resolution was also investigated. For the probe mixture used, the naphthyl column in combination with the addition of acetonitrile as co-solvent provided the best separation in terms of resolution. The SFC method was farther optimized for co-solvent composition, temperature, pressure, and flow rate. The SFC analysis showed high resolution and short analysis time compared to HPLC, and also provided for the separation of small components that have been attributed to impurities in the sample.

A BME-n a csoport altal korabban kifejlesztett igen hatekony szuperkritikus extrakcios reszolvalas tapasztalataibol kiindulva tovabbi enantiomer előallitasi modszereket fejlesztettunk. A vilagon elsőkent valositottunk meg in situ diasztereomer so kepzest tiszta szuperkritikus szen-dioxidban es kimutattuk, hogy a nyomas es a hőmerseklet befolyasolja a sokepzesi reakcio sebesseget es a diasztereomer sok egyensulyi aranyat is. A szuperkritikus szen-dioxidot antiszolvenskent alkalmazva nagy enantiomer tisztasagu (ee) es mikromeretű diasztereomer so kristalyositasara alkalmas eljarast dolgoztunk ki. A legfontosabb eredmenye az antiszolvens kristalyositason alapulo reszolvalasnak a “know how”, ami akar az ee ertek maximalizalasat akar a szemcsemeret eloszlas szabalyozasat lehetőve teheti. A harmadik modszer, aminek alkalmazhatosagat bemutattuk az a szuperkritikus szen-dioxid oldoszerben vegrehajtott enzimkatalizalt kinetikus reszolvalas, amit kedvező oldhatosagi viszonyok eseten termekelv...

Vitamins are compounds that take part in all basic functions of an organism but also are subject of number of studies performed by different researchers. Two groups of vitamins are distinguished taking into consideration their solubility. Chromatography with supercritical CO 2 has found application in determination, separation and quantitative analyses of both fat-and water-soluble vitamins. The methods of vitamins separation have developed and improved throughout the years. Both groups of compounds were separated using supercritical fluid chromatography with different detection on different stationary phases. The main aim of this review is to provide an overview of the studies of vitamins separation that have been determined so far.

Supercritical fluid extraction (SFE) of essential-oil constituents has absorbed much attention, especially in cosmetic, pharmaceutical and food industries, because it is an alternative to conventional processes such as organic-solvent extraction and steam distillation [1]. SFE of plant material with CO 2 allows its processing at low temperatures, therefore limiting the thermal degradation of its components, and avoiding the use of solvents prohibited in cosmetic or food products [1]. Moreover, it was shown that essential-oil constituents and light fractions of the resins are selectively extracted with this technique, producing an extract with the characteristics of the absolute [2]. Juniper berries, Juniperus communis L. (Cupressaceae), are a rich source of both volatile terpenes and lipophilic compounds with higher molar masses, such as resins and fats. The analysis of juniper berry supercritical extraction processes indicated unequivocally that, depending on the chosen process par...

Vitamins are compounds that take part in all basic functions of an organism but also are subject of number of studies performed by different researchers. Two groups of vitamins are distinguished taking into consideration their solubility. Chromatography with supercritical CO 2 has found application in determination, separation and quantitative analyses of both fat-and water-soluble vitamins. The methods of vitamins separation have developed and improved throughout the years. Both groups of compounds were separated using supercritical fluid chromatography with different detection on different stationary phases. The main aim of this review is to provide an overview of the studies of vitamins separation that have been determined so far.

Lavandula angustifolia is one of the most widely cultivated non-food crops used in the production of essential oil; it is used in perfumery, aromatherapy, pharmaceutical preparations, and food ingredients. In this study, supercritical fluid extraction (SFE) and molecular distillation (MD) were combined, primarily to enrich scCO 2 extracts with lavender oxygenated monoterpenes, avoiding thermal degradation, hydrolysis, and solvent contamination, and maintaining the natural characteristics of the obtained oils. Molecular distillation was developed for the first time for the extraction of crucial lavender fragrance ingredients, i.e., from two scCO 2 extracts obtained from dry flower stems of lavender cultivated in Poland and Bulgaria. The best results for high-quality distillates were obtained at 85 • C (EVT) and confirmed that linalyl acetate content increased from 51.54 mg/g (initial Bulgarian lavender extract, L-Bg-E) and 89.53 mg/g (initial Polish lavender extract, L-Pl-E) to 118.41 and 185.42 mg/g, respectively, corresponding to increases of 2.3 and 2.1 times in both distillate streams, respectively. The distillates, light oils, and extracts from lavender were also evaluated for their antimicrobial properties by determining the minimum inhibitory concentration (MIC) by the broth microdilution method. Generally, Gram-positive bacteria and Candida spp. were more sensitive to all distilled fractions and extracts than Escherichia coli (Gram-negative bacteria).

The separation of phenolic compounds by supercritical fluid extraction has been widely studied throughout the last two decades. This is evidenced by a number of publications and articles. Supercritical fluid extraction (SFE) has become thus the effective method of separating the mentioned group of compounds. On the other hand, SFE is a beneficial approach in plant waste materials utilization and reduction of environmental burdens caused by the wastes. The aim of the study is to gather and systematize available information on the phenolic compounds separation that have been reported so far as well as to evaluate whether there is one optimal supercritical fluid extraction method for the phenolic compounds.

Echinacea has been known for its immunostimulatory activity, and its alkylamide components have been linked to such biological activity. Consequently, alkylamides in Echinacea angustifolia were extracted using supercritical carbon dioxide from fresh and dried roots at 45-60 °C and 34-55 MPa, and the alkylamide yield in the extracts was determined. The yield of alkylamides from fresh roots increased with temperature yet decreased with pressure, whereas the yield from air-dried roots (moisture content 8.4%) increased with both temperature and pressure. Freeze-drying of the roots to a moisture content of 4.9% did not result in any further increase in the yield compared to that of air-dried roots. Alkylamide yield of the ground dried roots extract was the highest (p e 0.05) among those from fresh, ground and unground E. angustifolia roots. Supercritical fluid extraction therefore shows potential for the recovery of alkylamides from dried Echinacea roots.

A detailed summary on SFC-MS interfaces is given, with emphasis on current issues and potential solutions. • Differences between LC-MS and SFC-MS in terms of matrix effects generated are highlighted. • Sensitivity under SFC-MS has been demonstrated to be comparable to what it can be reached in LC-MS conditions. • Applications for SFC-MS are shifting towards the analysis of compounds with increasing polarity and analytes available in complex matrices.

The separation of oligomers of two different polymers using capillary supercritical fluid chromatography was studied. Pressure programming was used to achieve optimum separation of the oligomers. From a comparison of the separation of these oligomers with different length columns it was demonstrated that oligomer solubility was primarily controlling the separation. Accordingly, changing the stationary phase, shortening the column or not even using a stationary phase had minimal effect on the separation of the oligomers.

Linear velocity in capillary SFC is commonly controlled by restricting capillaries. In this paper, a model is described that quantitatively predicts the linear velocity of a supercritical fluid in SFC using tapered or ceramic frittype restrictors. In this model, the flow from the restricting capillary is assumed to be an isentropic expansion. The variation of the linear velocity as a function of pressure, temperature and cross-sectional area of the restricting aperture was predicted by this model. This predictive capability is important to the use of gradient programming in capillary SFC. Finally, the ideal variable restrictor for gradient programming was found to be one that could reversibly increase or decrease the linear velocity independent of the pressure, temperature, and/or density conditions used to create the gradient.

The resulk from extended studies of a porous glassy carbon (PGC) materlal for packed-column wpercrltlcal fluid chromatography (SFC) are reported. Low leveb of organic modifiers are used to change the solvent strength of the supercrltical carbon dloxlde moblle phase. A Ilnear model Is developed decrcrlblng solvent strength In terms of modifler molar volume, dlpdarlty, Lewis acidity, and Lewls baslctfy. The solvent strength In SFC PGC depends on the modifier molecular dze as well as modifier polarity. Solute retentbn Is controlled by molecular-level Interactions In the following order of importance: dlsperdon > Lewis acld-base > d i p larlty. The model was effectively used to choose a SFC moMle phaw crpproprlato for analysis of selected polar acfdlc solutes. X 20-cm-long fused silica column packed with Hypercarb PGC

from a prellmlnary evaluatlon of a porous glassy carbon (PGC) material for packed-column supercrltlcal fluid chromatography (SFC) are reported. The material Is characterlzed In terms of its retentlon characterlstlcs. Increasing temperature at constant pressure causes lnitlal increases In solute capaclty factors with subsequent slow decreases when sufficient temperatures (-145 "C) are reached. Varlatlon of temperature at constant carbon dloxide mobile phase densities yields enthalpies of Interaction for low molecular weight organlcs (C&,) from -0.5 to -1.5 kcal/mol. PGC Is highly retentive; use of a supercrltlcal fluid mobile phase that competes wlth solutes for adsorptlon onto the PGC allows slgnlflcant control of solute retention. PGC offers potential advantages not provided by other materials. PGC-SFC exhibits reverse-phase characterlstlcs slmllar to those found for PGC-HPLC, retention behavior previously unavailable In SFC. PGC Is highly stereospeclflc and will be useful in SFC applications requiring separations of Isomers and molecules with only slight structural differences.

The use of enhanced-fluidity liquid chromatography (EFLC) for chiral separations was demonstrated on a macrocyclic antibiotic column, Chirobiotic-V. This technique was compared to high performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC) for the separation of chiral compounds in normal-phase mode. The highest resolution was always observed for EFLC condition. Higher efficiency and shorter retention time were also observed for most separations with portions of CO 2 in the range of 0-50 mol %. Larger amounts of CO 2 caused efficiency to decrease and retention time to be prolonged. For some separations, the temperature was elevated to bring the mobile phase to the supercritical condition. Improved efficiency was obtained in SFC, whereas resolution and selectivity were worse. The use of EFLC in reversed-phase chiral separations was also tested. Enantiomer resolution improved under the EFLC condition. For the tested methanol/H 2 O mixture, fluoroform provided more significant improvements in chromatographic performance than CO 2 when used as a fluidity enhancing liquid. The use of EFLC instead of HPLC also caused a markedly lower pressure drop across the column for commonly used flow rates. The lowpressure drop will allow the use of longer columns or multiple columns to increase the total efficiency of the separation. Since chiral columns are often inefficient, this attribute may be very important for chiral separations.

The chromatographic application of a new lowtemperature method for the generation of glassy carbon is demonstrated. The glassy carbon is generated by heating a diethynyl aromatic oligomeric precursor to temperatures <lo00 OC. The unique glassy carbon precursor exhibits minimal mass loss during heating which allows the generation of glassy carbon films. In high performance liquid chromatography (HPLC) applications, this low-temperature glassy carbon (LTGC) has retention characteristics ranging from those observed with classical reversed-phase materials to those displayed by commercially-available glassy carbon supports. These "tunable" retention characteristics are easily controlled and determined by the final curing temperature. LTGC-coated silica supports were generated and used for HPLC, and LTGC-coated open tubular columns were prepared and used for supercritical fluid chromatography.

The first discussions on the use of inorganic gases above their critical point as mobile phase in chromatography systems stems back to 1957 1 and it was Klesper et al who reported on a preliminary study in which chlorofluorocarbons were used above their critical point to separate metal phophorins. 2 Supercritical fluid chromatography (SFC) with carbon dioxide as the mobile phase emerged in the late 1960s. In the past decade, a new generation of SFC instruments are commercially available and also the number of applications of SFC have grown considerably. Here, Susan Olesik, Caroline West, Davy Guillarme, Debby Mangelings, and Lucie Nováková share their thoughts on the technology and discuss the challenges and potential of SFC. Susan Olesik: I joined Milos Novotny's group in 1982. This was in the very early days of capillary Supercritical fluid chromatography. While I was in the Novotny group, we published the first SFC-FTIR interface. Caroline West: I started doing SFC as a PhD student. It was the only technique I was supposed to investigate for my thesis. I was drawn to the topic because my mentor convinced me that it was a technique worth learning, because there were still lots of unknowns. As one who This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Methanol/CO 2 phase behavior was investigated previously by a number of researchers. However, the entire composition range at moderate temperatures was not mapped in a single study. Extensive acetonitrile/CO 2 vapor-liquid phase information has not been reported. The goals of this research were twofold: (1) to demonstrate the accuracy and precision of visual observation for vapor-liquid phase boundary determination using a high-pressure, variable-volume view cell with the methanol/CO 2 system relative to the data available, and (2) to examine phase behavior of methanol/CO 2 and acetonitrile/CO 2, commonly used binary fluids for supercritical fluid chromatography and extraction, from 0-1.00 mole fraction CO 2 and over a 25-100°C temperature range. Results for methanol/CO 2 were found to be very comparable to the literature values.

The feasibility of a new technique, supercritical fluid chromatography/Fourier transform infrared spectrometry (SFC/FTIR), for separation and identification of nonvolatile and labile compounds in complex mixtures is discussed in this report. The design of a high pressure (flow cell) interface is described. The results of a continuing study of possible mobile phases for SFC/FTIR are presented. Finally, SFC/FTIR was applied to a standard test mixture. The current detection limits of one component of the mixture, 2,6-di-t-butylphenol, are presented.

The flame photometrlc detector (FPD) was optimized for the anaiysls of organosulfur compounds by supercrttlcal fluid chromatography (SFC). The flame gases used In thls study were hydrogen and oxygen. The optimum flow rates for hydrogen and oxygen were determined. The effect of placing the pressure restrictor dmerent distances away from the flame was examined. The flame chemisky that resunb when carbon dloxide flows Into a hydrogen-rich flame was characterized. The coelutlon of hydrocarbons wlth sulfur-containing compounds did not markedly quench the sulfur dimer signal for concentrations that were approprlate for capillary SFC. Detection limits as low as 0.1 ng of sulfur were achieved with detectivities of 8 pg/s.

Le Studium Conferences 2019 • selection of chemotypes adapted to climatic conditions along with suitable cultivation techniques. • provide an alternative to dominant local crops, i.e. cereals. • S. montana has developed several morphological and physiological adaptations, affecting oil yields and composition , which are related as well to geographical location and stages of plant development