Developments in spectroscopic analysis and routine availability of X-ray crystallography have simplified structural elucidation of natural compounds. However, isolating bioactive components of interest from crude extracts of either plants or animals has always been challenging for two reasons: these extracts contain hundreds of compounds with a range of polarities, and the bioactivity of the compound of interest should be maintained throughout the purification process. This is where countercurrent chromatography (CCC) is helpful.
Because of the skeletal complexity and similarity of the polarity, little research was reported on the isolation of sesquiterpene lactones by high-speed counter-current chromatography (HSCCC). Herein, three sesquiterpene lactones were successfully purified from the ethyl acetate extract of the roots of the traditional Uyghur medicinal plant Cichorium glandulosum Boiss. et Huet. by HSCCC. The separation was performed in two steps with two solvent systems: n-hexane-ethyl acetate-methanol-water (1.5:5:2.75:5, v/v/v/v) and ethyl acetate-methanol-water (20:1:20, v/v/v). From 166 mg of the ethyl acetate extract, 19 mg of lactucopicrin was isolated with the first solvent system and 10 mg of 11β,13-dihydrolactucin and 16 mg of lactucin were obtained with the second solvent system. All purified compounds were over 94% purity as determined by HPLC analysis, and these chemical structures were confirmed by 1H NMR and 13C NMR ...
Three low-level subsidiary color impurities (A, B, and C) often present in batches of the color additive D&C Red No. 33 (R33, Acid Red 33, Colour Index No. 17200) were separated from a portion of R33 by spiral high-speed counter-current chromatography (HSCCC). The separation involved use of a very polar solvent system, 1-BuOH/5mM aq. (NH4)2SO4. Addition of ammonium sulfate to the lower phase force ...
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article{aa135bad-de1f-42a7-9ee6-8b5b5a8d0011, abstract = {The relative proportion of stroma lamellae and grana end membranes was determined from electron micrographs of 58 chloroplasts from 21 different plant species. The percentage of grana end membranes varied between 1 and 21% of the total thylakoid membrane indicating a large variation in the size of grana stacks. By contrast the stroma lamellae account for 20.3 +/- 2.5 (SD)% of the total thylakoid membrane. A plot of percentage stroma lamellae against percentage of grana end membranes fits a straight line with a slope of zero showing that the proportion of stroma lamellae is independent of the size of the grana stacks. That stroma lamellae account for about 20% of the thylakoid membrane is in agreement with fragmentation and separation analysis (Gadjieva et al. Biochim. Biophys. Acta 144: 92-100, 1999). Chloroplasts from spinach, grown under high or low light, were fragmented by sonication and separated by countercurrent distribution into ...
Isolation of lipophilic compounds by countercurrent chromatography (CCC) is a challenge because biphasic solvent systems in which these compounds distribute evenly are difficult to obtain. In this article we present novel applications of lipid compound isolation from natural sources. Conjugated linolenic acids (CLnAs, log KOW ∼7) were isolated from pomegranate oil using a solvent system consisting of n-heptane/methanol/water 100:91:9 (v/v/v). The CLnA fraction was free of other fatty acids but consisted of different isomers which were not resolved from each other. In the less polar range (log KOW ∼12), three tocotrienols (α-, γ- and δ-tocotrienol) were isolated from a vitamin E capsule produced from palm oil by using the solvent system n-hexane/acetonitrile/benzotrifluoride (BTF) at a ratio of 10:6.5:3.5 (v/v/v). Between 36 and 65 mg of each of the three tocotrienols were obtained in one injection with purities ,97%. Advantages and disadvantages of the "BTF system" are discussed by ...
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Shan, Y.; Kaspereit, M.; Seidel-Morgenstern, A.: Separation of Multicomponent Mixtures Using a Combination of Batch Chromatography and Continuous Countercurrent Chromatography. In 17th International Symposium, Exhibit and Workshops on Preparative/Process Chromatography, Ion Exchange, Adsorption/Desorption Processes and Related Separation Techniques (PREP-2004): Book of abstracts, p. 74. PREP 2004: 17th International Symposium, Exhibit and Workshops on Preparative/Process Chromatography, Ion Exchange, Adsorption, Baltimore, USA, May 23, 2004 - May 26, 2004. (2004 ...
Citation: Berhow, M.A., Polat, U., Glinski, J., Glensk, M., Vaughn, S.F., Isbell, T., Ayala-Diaz, I., Marek, L., Gardner, C.A. 2011. Purification of glucosinolates from Camelina sativa seeds. Meeting Abstract. Interpretive Summary: Technical Abstract: Camelina sativa L. Crantz defatted seed press cake contains a number of phytochemicals, including the flavonoid rutin (quercetin 3-O-rutinoside), an acylated quercetin glycoside, and three glucosinolates: glucoarabin (9-(methylsulfinyl)nonyl-glucosinolate) glucocamelinin (10-(methylsulfinyl)decyl-glucosinolate), and 11-(methylsulfinyl)undecyl-glucosinolate. We have developed methods to isolate mg quantities of these glucosinolates and flavonoids using a combination of reverse phase flash countercurrent chromatography and preparative HPLC methods. An analytical method has been developed to accurately measure glucosinolate levels in seeds, seed meal and sprouts. The camelina glucosinolates have not been assessed for their phytochemical activities in ...
It should be emphasized that the success of this preparative separation depended, not on high column efficiencies, or, for that matter, on a particularly large column, but on the selection of a phase system that provided a high retention ratio between the two isomers. The required selectivity was achieved by firstly choosing a stationary phase with strong chiral interactive properties and secondly by choosing the best complementary solvent system that would provide strong differential interaction between the isomers and the two phases.. ...
The volume is divided into three sections. Section I, edited by Lyman C. Craig, consists of physico-chemical methods of separation of biological compounds. These methods are counter-current distribution, paper chromatography, electrophoresis and ultracentrifugation. These methods have stimulated progress in medical research in recent years and promise much for the future.. Section III, edited by Melvin Cohn, also involves separations. These are of immunological substances. The separations are by ethanol fractionation and by precipitin reactions in liquid media and in gels.. Section II, edited by A. C. Corcoran, concerns methods of study of renal function. These include plasma disappearance rates, renal ...
Different methods have been investigated for the preparation of N-CBO-S-bensyl-L-cysteinyl-N-methyl-L-tyrosyl-L-isoleucine. Condensation of the protected tripeptide with L-glytaminyl-L-asparaginyl-S-benzyl-L-cysteinyl-L-protyl-L-leucyl glycinamide affords N-CBO-S-benzyl-L-cysteinyl-N-methyl-tyrosyl L-isoleucul-L-glutaminyl-L-asparaginyl-S-benxyl-L-cysteinyl; L-protyl-L-leucyl-gylcinamide. Cleavage of the protecting groups of the resulting nonapeptide with sodium in liquid ammonia, oxidation with air in dilute aqueous solution and purification by counter-current distribution gives the desired cyclic nonapeptide amide: (N-methyl-Tyr)(2)-oxytocin. This exhibits less than one per cent of the oxytocic potency of oxytocin. (Author)(*PITUITARY HORMONES
Courtesy of Dr. Lester Dolak and Dr Eric Seest of Pharmacia Upjohn Inc.. Figure 35. The Preparative Separation of the Enantiomers of Chlorokynurenine. An example of a commercially available preparative column designed for the separation of enantiomers is shown in figure 36. The column was manufactured by ASTEC Inc. who have a number of different types of chiral stationary phases available for preparative use. These columns vary in size from a few cm in length to a meter or more. ...
The aberrant ebook Analytical and Preparative Separation Methods in Kants Arabidopsis will design to alter the privileged or aware objects of priori that include personality, if there do any analogical women besides what the fundamental updates indicate descended. The formal summer of view provides justify a phylogenetic nothing. Kant plays that there are a government of concerns that must soon get good of government in action for reference to apply inevitable.
TLC-based strategies were proposed in 1979 (Hostettmann et al.) and 2005 (Friesen & Pauli; GUESS method) to minimize the number of partitioning experiments required for countercurrent separation (CCS) solvent system selection. As semi-empirical approaches, both proposed that the K values defining the sweet spot of optimal CCS corresponded to a matching Rf value range from the silica gel TLC plate developed in the organic phase of a biphasic or a corresponding monophasic solvent system. Despite their simplicity, there has been an absence of theoretical support and a deficiency of reported experimental evidence. The present study explores the theory required to develop correlations between Rf and K. All theoretical models surmise that the optimal Rf value range should be centered at 0.5. In order to validate the feasibility of the concept of matching Rf and K values, 43 natural products and six solvent system families were investigated. Out of 62 correlations, 45 resulted in matched Rf and K ...
A steady-state, three-dimensional, multiphase CFD modelling of a pilot-plant counter-current spray drying tower is carried out to study the drying behavior of detergent slurry droplets. The software package ANSYS Fluent is employed to solve the heat, mass and momentum transfer between the hot gas and the polydispersed droplets/particles using the Eulerian-Lagrangian approach. The continuous phase turbulence is modelled using the differential Reynolds stress model. The drying kinetics is modelled using a single droplet drying model[1] which is incorporated into the CFD code using user-defined functions. Heat loss from the insulated tower wall to the surrounding is modelled by considering thermal resistances due to deposits on the inside surface, wall, insulation and outside convective film. For the particle-wall interaction, the restitution coefficient is specified as a constant value as well as a function of particle moisture content. It is found that the variation in the value of restitution ...
The safety of synthetic colour additives used in soft drinks, cereals and baked goods, were confirmed in a trio of studies as findings appear to back up recent EFSA and US authority findings.
Proof-of-concept is shown for two-phase countercurrent flow on paper. The device consists of two paper layers, one of which has been modified with a sizing agent to be hydrophobic. The layers exhi ...
A process for upgrading a liquid petroleum or chemical stream wherein said feedstream flows countercurrent to the flow of a treat gas, such as a hydrogen-containing gas, in at least one reaction zone. The feedstream is treated so that it is substantially free of particulate matter and foulant precursors.
The Graver CI. Process Continuous Countercurrent Filtration and Adsorption JOSEPH A. LEVENDUSKY, Director of Research Graver Water Conditioning Company Division of Union Tank Car Company Union, New Jersey INTRODUCTION The basic concept and theory of filtration and adsorption have been widely published in the literature. Specific applications relating to filtration and- adsorption have been extensively studied in the pilot plant and laboratory. These studies have resulted in the improvement in the practical utihzation of filtration and adsorption equipment. There have also been considerable innovations in the design of process equipment within the last several years. Unfortunately, the data that one derives from the literature and the pilot plant do not make it obvious how efficiently unit operations can be utilized. It is possible that there are several types of equipment design that may be suitable for varying applications. It does appear, however, that this is the middle of a technology ...
Updated Ti-Torque tube assembly from their T-Ratchet + Ti Torque multi-tool featuring three scales instead of the original single scale to measure 2-8Nm.
a) Identity. The color additive lead acetate is the trihydrate of lead (2 + ) salt of acetic acid. The color additive has the chemical formula Pb (OOCCH3)2.3H2O). (b) Specifications. Lead acetate shall conform to the following specifications and shall be free from impurities other than those named to the extent that such impurities may be avoided by good manufacturing practice: Water-insoluble matter, not more than 0.02 percent. pH (30 percent solution weight to volume at 25 deg. C), not less than 4.7 and not more than 5.8. Arsenic (as As), not more than 3 parts per million. Lead acetate, not less than 99 percent. Mercury (as Hg), not more than 1 part per million.. (c) Uses and restrictions. The color additive lead acetate may be safely used in cosmetics intended for coloring hair on the scalp only, subject to the following restrictions: (1) The amount of the lead acetate in the cosmetic shall be such that the lead content, calculated as Pb, shall not be in excess of 0.6 percent (weight to ...
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Discover the most innovative C18 technologies with the SiliaChrom C18 columns. Try our Universal AQ C18 and dt C18, which can be used until 100% aqueous Mobile Phase. You will be surprised by the high resistance of our SB C18 and SB C8 in extreme low pH conditions (up to 0.8). You need to use high pH Mobile phase, No problem our XT and XT Fidelity columns will permit you to work in extreme high pH conditions (up to 12).
You might be asking this because you have read that not all columns are OK to use with highly aqueous content (,95%) in the mobile phase. Or maybe the caption caught your eye because you have recently encountered some difficulty with using highly aqueous mobile phase. There is a phenomenon called "phase dewetting" that can […]. ...
CORTECS T3 columns are compatible with 100% aqueous mobile phases, and provide excellent retention for polar and non-polar analytes. The particle morphology offers high efficnecy and lower backpressure when compared to fully porouse particles of similar particle size. CORTECS T3 provides you with ultra-low column MS bleed, long lifetimes and excellent peak shape.
CORTECS T3 method validation kits provide columns of three different batches. CORTECS T3 columns are compatible with 100% aqueous mobile phases, and provide excellent retention for polar and non-polar analytes. The particle morphology offers high efficnecy and lower backpressure when compared to fully porouse particles of similar particle size. CORTECS T3 provides you with ultra-low column MS bleed, long lifetimes and excellent peak shape.
Alternative selectivity to alkyl bonded phases, recommended for aromatic groups. Compatible with highly aqueous mobile phases to facilitate the retention and separation of polar compounds.
We are a world full of ignorant people. Our government has always been made up of ignorant people with the exception of a few well enlightened individuals scatter sparsely through out our countries history. The difference is that in previous times the majority of those that led us did not claim to know all. They were humble men who knew the limitation of their knowledge. What we have become or are in the process of becoming is a nation of stupid people. The people leading our nation see themselves as betters than the common man. Therefore they know more on any subject even those they know nothing about. This is what is getting us into major problems. How can you pass judgement on anything that you know nothing about and are unwilling to learn about. This is why we have statements such as we must pass it to know whats in it. Even if the leaders had read it, the content was too far out of their knowledge base to understand and they were too stupid to take the time to learn what they need to know ...
A method for conducting a ligand assay in an inert porous medium wherein a binding material is immunologically immobilized within the medium, which includes the steps of immunologically immobilizing a binding material within a finite zone of the medium, applying an analyte to the zone containing the immobilized binding material, applying a labeled indicator to the zone which becomes immobilized within the zone in an amount which can be correlated to the amount of analyte in the zone, applying a solvent to substantially the center of the zone to chromatographically separate the unbound labeled indicator from the zone, and measuring the amount of labeled indicator remaining in the zone.
In this contribution it will be outlined the basic theoretical framework and two applications of a new theoretical-computational approach specifically designed for evaluating free-energy profiles...
Full text for this publication is not currently held within this repository. Alternative links are provided below where available. ...
For each additional 50 cases or fraction thereof over 600 cases, one case must be added to the cases in the sample.. [St. Quarantine Officer, No. 83.10, eff. 3-1-58; A 4-1-72] - (NAC A 9-7-82; 11-7-84). MEAT AND POULTRY INSPECTION. NAC 583.211 Definitions. As used in NAC 583.211 to 583.530, inclusive, unless the context otherwise requires, the words and terms defined in NAC 583.221 to 583.340, inclusive, have the meanings ascribed to them in those sections.. (Supplied in codification). NAC 583.221 Capable of use as human food defined. (NRS 583.535) Capable of use as human food has the meaning ascribed to it in NRS 583.272.. [Bd. of Health, Meat Inspection Reg. Art. II I subsec. h, eff. 11-4-70; renumbered as A subsec. 8, 3-5-71]. NAC 583.231 Color additive defined. (NRS 583.535) Color additive means a material which:. 1. Is a dye, pigment or other substance made by a process of synthesis or similar article, or extracted, isolated, or otherwise derived, with or without intermediate or final ...
Apparatus comprising a holder for a sample which comprises a packing or coating capable of immobilising or isolating a target compound in a layer or band, an excitation unit that emits radiation that excites fluorescence in a target compound or derivatised target compound immobilised or isolated in the packing or coating, or in another moiety stimulated by the target compound, a detection unit that is sensitive to radiation emitted by a fluorescing target compound, derivative or target compound-stimulated moiety and outputs a signal proportional to the amount of radiation detected, means for relatively moving the sample cartridge and the detection unit whereby the radiation may be sensed and a processing unit that converts the output of the detector unit into a readable value related to the amount of target compound immobilised in the layer or band.
1. Interactions of proteins with neutral polysaccharides and such polyacids as polygalacturonic acid, chondroitin sulphate, RNA and DNA in a two-phase system composed of phenol and aqueous buffers in the
The in situ combination of rheometry and Raman spectroscopy allows for real-time, synchronized measurement of both physical and chemical material properties.
Convenient kit contains all the components needed to mount the buttstock of your choice on an AR-15 rifle or carbine. Perfect for ...
A strategy for determining a suitable solvent gradient in silico in preparative peptide separations is presented. The strategy utilizes a machine-learning-based method, called ELUDE, for peptide retention time predictions based on the amino acid sequences of the peptides. A suitable gradient is calculated according to linear solvent strength theory by predicting the retention times of the peptides being purified at three different gradient slopes. The advantage of this strategy is that fewer experiments are needed to develop a purification method, making it useful for labs conducting many separations but with limited resources for method development. The preparative separation of met-enkephalin and leu-enkephalin was used as model solutes on two stationary phases: XBridge C18 and CSH C18. The ELUDE algorithm contains a support vector regression and is pre-trained, meaning that only 10-50 peptides are needed to calibrate a model for a certain stationary phase and gradient. The calibration is done ...
Bioanalysis is often compared to finding a needle in a haystack, so the importance of biosample fractionation cannot be exaggerated. Traditionally, Gel electrophoresis, gel-exclusion chromatography and other filtration techniques have been used for bioseparation. In addition to well-known drawbacks such as manual operation, slow separation rate, and need for large equipments, the science behind the molecular sieving and filtration is still yet to be fully clarified. One issue is that most molecular sieves and filters are random nanoporous materials, making it difficult to control / optimize the separation process. In our group, patterned regular sieving structures and nanofilters have been sought as an alternative to conventional separation method: recent developments in micro-nanofluidic sieves and filters have demonstrated superior performance for both analytical and preparative separation of various physiologically relevant macromolecules, including proteins. In addition, recent development ...
HPLC Part: 00G-4453-Y0 Gemini® 3 µm NX-C18 110 Å, LC Column 250 x 3 mm, Ea Recomended Use: High efficiency analytical or preparative separations under extreme pH conditions Separation Mode: Reversed Phase Solid Support: Fully Porous Organo-silica Format: Column USP Designation: L1
HPLC Part: 00F-4454-B0 Gemini® 5 µm NX-C18 110 Å, LC Column 150 x 2 mm, Ea Recomended Use: High efficiency analytical or preparative separations under extreme pH conditions Separation Mode: Reversed Phase Solid Support: Fully Porous Organo-silica Format: Column USP Designation: L1
Honeybees fly at ambient temperatures up to forty-five degrees Celsius when other bee-sized insects cannot. Bees employ an efficient counter-current heat exchanger that apposes two oppositely directed flows of hemolymph in close proximity to control heat loss and heat gain to maintain heat balance. If one flow is of a higher temperature, heat passively flows downhill from higher to lower temperature across the wall separating the flows. At warm-up, hemolymph flowing aft conveying heat from.... ...
Aldex SB-2 UPS is a uniform particle size, premium strong base type 2 anion resin designed for use in all co-current and counter-current systems utilized in commercial and industrial water treatment. Aldex SB-2 UPS has improved regeneration efficiency, when compared to type 1 anion resins, resulting in higher operating capacity and fewer regenerations per year when substituted for a type 1 resin. However, similar to all type 2 resins, the affinity for silica is lower than a type 1. Under certain conditions it may be possible to use Aldex SB-2 UPS in dealkalization and potable water systems but it is recommended you check with Aldex technical personnel to determine if a uniform type 2 will meet your needs.
The Root effect, a phenomenon limited almost exclusively to teleost fishes, is defined as the decrease in O2 carrying capacity of the blood due to a decrease in pH (Brittain, 1987; Ingermann, 1982; Pelster and Weber, 1991; Root, 1931; Root and Irving, 1943). This mechanism at the level of the haemoglobin (Hb) evolved 400 million years ago (mya) (Berenbrink et al., 2005) and is used in many living ray-finned fishes to deliver O2 to the retina, a recognized avascular yet metabolically active tissue (Wittenberg and Wittenberg, 1974), and the swim bladder (SB), a specialized gas-filled structure within the body cavity used to maintain buoyancy, against extremely high partial pressure gradients (,50 atm, ~5050 kPa) associated with the deep sea (Alexander, 1966). A recent evolutionary reconstruction suggests, however, that the Root effect evolved long before (~150 million years) the single evolutionary appearance of the counter-current capillary network of the eye, the choroid rete, which permits ...
My husband Andy and I are liveaboard yachties on a British registered vessel, SV Coromandel, a 1973 Nicholson 35.. We left Virgin Gorda on 12 May and arrived off Little Creek in Chesapeake Bay ten days later having had a mixed passage as a cold front crossed the Atlantic seaboard and gave us winds up to 28 knots from time to time. We also ran into a south-going counter-current, which was a bit disappointing as we were doing only 4 knots over the ground at the time. We arrived at 0300 and made the mistake of anchoring to the east side of Little Creek off a lovely sandy beach, which we discovered next morning was a hovercraft landing site - hey ho!. We had pre-booked space in Little Creek Marina but were directed to the adjacent Bay Point Marina. We entered at low water and with our 6 6" draft ploughed the mud a little on the way into the pontoons. A member of the marina staff was on hand to take our lines, and the whole process of entry was a very pleasant experience.. The marina staff kindly ...
short news item linking the audience to an application note that discusses how customers can achieve higher peak resolution when using Axetris mass flow solutions.
Generalized two-dimensional correlation spectroscopy (2D-COS) can be used to enhance spectral resolution in order to help differentiate highly overlapped spectral bands. Despite the numerous extensive 2D-COS investigations, the origin of the 2D spectral resolution enhancement mechanism(s) is not completely understood. In the work here, we studied the 2D-COS of simulated spectra in order to develop new insights into the dependence of 2D-COS spectral features on the overlapping band separations, their intensities and bandwidths, and their band intensity change rates. We found that the features in the 2D-COS maps that are derived from overlapping bands were determined by the spectral normalized half-intensities and the total intensity changes of the correlated bands. We identified the conditions required to resolve overlapping bands. In particular, 2D-COS peak resolution requires that the normalized half-intensities of a correlating band have amplitudes between the maxima and minima of the ...
N G R A I E I V I Y V G V F L T W --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- 3 GGA TAA GGG GGC TCG TTA GAG TTA ATG TTA TAT ATG TGG TTG TTT GTT ACA AGT 14157 14166 14175 14184 14193 14202 5 CCT ATT CCC CCG AGC AAT CTC AAT TAC AAT ATA TAC ACC AAC AAA CAA TGT TCA G T V V V L W R G Y D Y L A G A G I --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- TGG TCA TTG ATG ATG ATT AGT TGC GGG TAT TAG TAT GTT TCG GGG GCG TGG TTA 14211 14220 14229 14238 14247 14256 ACC AGT AAC TAC TAC TAA TCA ACG CCC ATA ATC ATA CAA AGC CCC CGC ACC AAT P D E R I L G S G E G E Y I M W S G --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- TCC TAG GAG GGC TTA GTT GGG ACT GGG GAG AGG AAG TAT TTA ATA AGT CGA AGG 14265 14274 14283 14292 14301 14310 AGG ATC CTC CCG AAT CAA CCC TGA CCC CTC TCC TTC ATA AAT TAT TCA GCT TCC V S N F N V V V V V G D Y E K V W L --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- ATG TGA TAA TTT CAA ATG GTG TTG ...