Seplite

When the operation is carried out for a certain period of time, the resin bed will be divided into a saturated resin zone, a mass transfer zone, and a fresh resin zone. As the run time increases, the mass transfer zone gradually decreases until the bottom of the bed is penetrated by the mass transfer zone and the entire resin layer fails. For one application, the  fixed bed system  is usually operated in single column or two columns in series, plus a column for regeneration.

The whole section of resin in the  original fixed bed  is divided into several sections, and different sections of resin play different roles at the same time, so that the various sections of the original fixed bed adsorption, washing, desorption, regeneration and the like are integrated into one system equipment. By using the part of the resin that was originally idle, this greatly improves the resin utilization rate while reducing the chemical consumption through an effective connection operation mode. Advantage:  Integrate all steps, continuous operation, and strong system matching. Compact structure, less piping and less floor space. High resin utilization. High product yield, concentration and purity, and good stability. Less water and chemical reagents. Good operational flexibility according to the change of production load. Adjust valve switching speed or adjust flow rate. Three wastes are rarely emitted, reducing environmental pressure. Typical...

The biotechnology industry is the most promising industry in the 21st century. With the development of biotechnology, the industrialization of biological products has increasingly become a concern of people. In the production process of biological products, the separation and purification of products, especially the separation and purification of active macromolecules, has become a recognized key link in the downstream technology of bioengineering, which determines the prospect of industrialization of biological products. Chromatographic separation technology  is a kind of separation method widely used in the separation and purification of complex mixtures. Various chromatographic methods involve common basic features: there is a stationary phase and a mobile phase, when the biological mixed stock solution (mobile phase) passes When a tube or column (stationary phase) is filled with a bead or matrix material, the physicochemical properties (such as attractiveness, solubility, molec...

The process of separation and purification of biomacromolecules by ion exchange chromatography is mainly carried out by using the dissociation properties of various molecules, the net charge of ions, and the electrical difference of surface charge distribution. It has become one of the most frequently used purification techniques for the separation and purification of biochemicals, proteins, peptides and other substances. In the separation and purification, the column is required to have high loading capacity, easy operation and long service life. The separation medium is the most important factor. Therefore, the selection of the separation medium is particularly important. 1.1 Selection of varieties: A suitable  ion exchange chromatography medium  should be selected according to the type of charge, the size of the molecule, the physicochemical properties and the microenvironment of the target product to be separated and purified. For inorganic small molecules, the choice of s...

pH is an important factor in the operation of ion exchange chromatography, and pH stabilization and changes are usually achieved with buffers, so the choice of buffer is an important factor affecting the separation. When selecting a buffer, pH and ionic strength are two key factors that affect not only the separation of the target product from the impurities, but also the yield of the product. The pH chosen depends on the isoelectric point, stability and solubility of the target product, not only to make the separated material an ion that can be exchanged, but also to maintain its high activity. The pK value of the ion exchanger should also be considered. Since the buffer itself is charged, it is also combined with the  ion exchange chromatography medium . This combination will cause two kinds of interference, on the one hand, reducing the concentration of the buffer, thereby reducing the buffering capacity; on the other hand, it is exchanged with the separation medium to compete w...

In the industrial products of ion exchangers, a small amount of organic oligomers and some inorganic impurities are often contained, which will gradually dissolve and release at the initial stage of use, affecting the quality of the target product. Therefore, industrial grade ion exchangers must be pretreated prior to use. The general-purpose ion exchange resin is usually treated with acid or alkali, and can be treated with 1~2 mol/L hydrochloric acid and sodium hydroxide solution in an alternate 4~6 times resin bed volume, between acid and alkali treatment. Wash with deionized water until neutral. For macroporous resins, it is also necessary to treat them with an organic solvent such as ethanol or acetone to remove organic residues used in the production process. Pretreatment of the separation medium not only improves its working capacity, but also improves the purity of the separated product. The pretreated resin should eventually be converted to the applicable ionic form during the ...

When the chromatographic medium is exhausted, it should be eluted. The basic principle is to desorb the target product by a more active ion or group. Different sorbents are different in their activity. Therefore, a suitable eluent should be selected to elute the protein from  chromatography media . There are roughly three ways to elute ion exchange chromatography: One is for simultaneous elution. The eluent is a dilute acid, alkali or salt solution may be used, and an appropriate organic solvent may also be used, wherein the salt solution is mainly used, and the dosage form according to the nature of the target product and the final product is selected. Since the substance to be absorbed is often not a single species, the charge of each substance is different, and the binding strength to the medium is different. Even if the same eluent is used, the easily replaced substance will flow out of the medium first, and the binding force is strong. After the material is discharged, as long...

Polypeptide synthesis on a solid support, a concept of originality pioneered by Robert Bruce M Merrifield in 1963, is a major breakthrough in peptide chemistry.  In solid phase synthesis, it is conventional to assemble peptide chains starting from the C-terminus. First, a linker is introduced on the polymer carrier; then, the N-terminal protected amino acid reacts with the functional group of the linker; then the temporary protecting group is removed and condensed with the next amino acid, and this step is repeated until synthesis is required The sequence; finally, cleaves the covalent bond between the tether and the peptide chain, and removes the insoluble carrier from the dissolved product. The  solid phase synthesis  method effectively avoids the cumbersome and time-consuming separation and purification steps necessary for liquid phase synthesis, and has remarkable advantages, and its application value is irreplaceable.

The Boc/Bzl (tert-butoxycarbonyl/ /benzyl) method is a classical  peptide solid phase synthesis method  in which Boc is used as a temporary protecting group in combination with a benzylic semi-permanent side chain protecting group. Boc is unstable to acid and is usually removed with 20% to 50% TFA. The main strategy of the oc synthesis method is that the Boc which can be removed by TFA is an α-amino protecting group, and the side chain is protected by a benzyl alcohol. A Boc-amino acid derivative is covalently cross-linked to a Merrifield or M BH A resin during synthesis, Boc is removed by TFA, the free amino terminus is neutralized with triethylamine, and then the next amino acid is activated by DCC. Finally, the HF method or the TFM SA method is used for the deprotection. Although the Boc method is gradually replaced by the Fm oc method, since the Boc-amino acid is easily crystallized, it is easy to be acid-decomposed, has stability, and is easy to store for a long time. It ...

The Fmoc method is a new method for  solid phase synthesis of peptides  developed by Carpino and Hart based on the Boc method. The fundamental difference between the Fmoc/t-Bu(9-fluorenylmethoxycarbonyl/tert-butoxy) strategy and the Boc/Bzl strategy is the use of alkali-removable Fmoc is a protecting group for α-amino group, the side chain is protected by t-Bu which can be removed by TFA, and the solid phase carrier Wang resin with acid-sensitive linking arm is used, and the final step of the synthesis is removed by TFA. Han Xiang et al. successfully synthesized the 32-peptide thymosin α 1 by Fm oc solid phase method, starting from Fm oc-Asn(Trt)-W angResin, Boc protecting the side chain amino group of Lys, and tert-butyl ester group (O-t-Bu Protecting the side chain carboxyl group of Asp and Glu, t -Bu protects the side chain hydroxyl group of Ser and Thr, and trityl group (Trt) protects the side chain amide group of Asn, and the total synthesis yield is 33.2%, and the purity...

The immobilized enzyme is a biological reagent with high efficiency, high selectivity and mild reaction conditions. The immobilized enzyme immobilizes the enzyme onto an inert, low-water-soluble substance, so that the enzyme is immobilized in the reaction, and thus can be easily separated from the reaction system and used again. This technology has great commercial value and has been widely used in industrial enzymatic reactions. Enzyme immobilization method: Affinity-tag binding: The enzyme is adsorbed on the outside of the inert substance. In general, this method is the slowest of the three methods listed here. The adsorption reaction is not a chemical reaction, so the active site of the immobilized enzyme may be blocked by the matrix, thereby greatly reducing the enzyme activity. Entrapment: Enzymes are embedded in insoluble columns or microspheres, such as calcium alginate columns. However, this insolubility hinders substrate entry or product removal. Cross-linking method: ...

In the immobilized enzyme technology, factors such as the active group, the microenvironment, and the shape of the carrier on the carrier material may affect the affinity of the carrier and the enzyme, the activity, stability, reusability and recyclability of the immobilized enzyme.  Most of these materials have large specific surface area, a certain pore diameter, good hardness and mechanical strength, and easy surface modification or coating characteristics, can be studied by the carrier material before and after immobilized enzyme morphology The structure, element composition, specific surface area and pore size change, further analysis of the immobilization of the carrier material, therefore, the selection and characterization of the  immobilized enzyme carrier  is very important for the effective immobilization of the enzyme. There are three main types of carrier materials for immobilized enzymes: 1. Inorganic carrier material Mainly mesoporous materials, meso...

The full name of the catalytic resin is an ion exchange resin type catalyst. The H-type cation exchange resin can be used as an acid catalyst, and the anion exchange resin can provide a hydroxide, so it can be used as a basic catalyst. Currently, acidic solid catalysts have developed rapidly. The  resin catalyst  acts as a solid acid or a base catalyst in the same manner as a conventional acid or base catalyst such as sulfuric acid, hydrochloric acid or sodium hydroxide (potassium) in a homogeneous solution. It can be used to catalyze condensation reaction, addition reaction, elimination reaction, and molecular rearrangement. The catalytic reaction of the  ion exchange resin  is small in pollution, simple in equipment, mild in reaction conditions, and the process of separation and purification after the reaction is simplified, and the catalyst used can be recovered by a simple method. The current mature resin catalytic technologies are: 1. MTBE synthesis complete tec...

1. Adjustable catalytic activity The resin can be made into resin catalysts of different shapes, structures and load capacities depending on the application. The reactive groups of the macroporous resin are generally on the surface of the macropores and are readily accessible to the reactants. When it is desired to reduce the load capacity, some acid groups may be partially neutralized by acid-base titration, or some metal ions or groups having a catalytic effect may be introduced by partial ion exchange to increase the activity or selectivity of the catalyst. 2. The wide application The granular and porous structure of the resin makes it suitable for both gas phase and liquid phase reactions, as well as non-aqueous systems. Since the resin catalyst has such physical properties, after the reaction is completed, the catalyst can be separated from the reaction mixture by a simple filtration method, and the post-treatment of neutralization, washing, drying, distillation, etc. after the us...

The resin catalyst has been washed with pure water before leaving the factory, and can be washed without water after being charged into the reactor. Otherwise, it must be washed with demineralized water. The resin catalyst must be stored underwater and pretreated with methanol before use. By utilizing the characteristic that methanol and water can be mutually soluble, according to the principle of concentration action, methanol can form a certain concentration of methanol-water solution with water, thereby taking the water contained in the resin catalyst out of the reaction system. When the  resin catalyst  is pretreated with methanol, it is not enough to simply immerse in methanol, and dynamic circulation is required until the methanol concentration is constant. The time for methanol pretreatment is generally 12 to 24 hours.

Adsorbent resin, also known as polymer adsorbent, is a kind of high molecular polymer which has the function of adsorption and concentrates and separates organic matter.  According to the surface properties of the resin, the adsorption resin is generally classified: non-polar adsorption resins which are obtained from a monomer polymer having a small dipole moment. A typical example of an adsorption resin having any functional group is an adsorption resin of a styrene-divinylbenzene system; a medium polarity adsorption resin means an ester-containing adsorption resin such as acrylate or methacrylate and dimethacrylate. A type of copolymer which is cross-linked; a polar adsorption resin refers to an  adsorption resin  containing a nitrogen, oxygen, sulfur polar functional group such as an amide group, a cyano group or a phenolic hydroxyl group.

The adsorption is mainly based on the principle of van der Waals force or hydrogen bonding to produce adsorption. Because the adsorption resin has a large pore structure, the adsorption resin also combines the principle of molecular sieve. The surface characteristics of the  adsorbent resin  determine the target that it can separate, generally following the following rules: Non-polar sorbents can adsorb non-polar materials from polar solvents Polar adsorbents can adsorb polar substances from non-polar solvents Medium polarity adsorbent combines both of these capabilities The main factors affecting adsorption;  1.The nature of the adsorbent, specific surface, particle size, polarity 2.The nature of the target, solubility, surface tension, molecular weight 3.Temperature; adsorption is an exothermic process, low temperature is good for adsorption, high temperature is good for analysis 4.The pH of the solution, which affects the degree of dissociation of the target 5. Salt...

The adsorption resin is mainly formed by suspension polymerization, and the pores are formed inside the resin through the addition of the porogen, followed by rinsing, sieving and the like. 1.Non-polar adsorbent resin Mainly use styrene and divinylbenzene as raw materials, choose the appropriate porogen and dosage. 2. Medium polarity adsorbent resin The acrylate monomer is mainly introduced into the non-polar adsorption resin, so that the resin structure has a certain polarity. 3. Polar adsorbent resin It mainly contains a polar group, a nitrile group, a sulfone group, an amide group, and an amino group. A.  adsorbent resin with Nitrile group Polymerization of acrylonitrile and divinylbenzene B.  adsorbent resin with Sulfone group It is a low crosslinked polystyrene sphere which is crosslinked by thionyl chloride. C.  adsorbent resin with Amide group The nitrile-containing  adsorption resin  is obtained by aminolysis of ethylenediamine; it can also be prepared b...