China Wuhan Desheng Biochemical Technology Co., Ltd Company News

Blood analysis is a routine test item in clinical medicine. The vast majority of outpatients or inpatients are subject to this test. From the beginning of the development of manual detection to automatic detection. EDTA is an anticoagulant commonly used in hematology analyzer. It has good anticoagulant effect and little effect on blood cell morphology.   Potassium ethylenediaminetetraacetate (edta-k2)   Ethylenediaminetetraacetic acid (EDTA) is an amino polybasic acid. Because it can form complex with most metal ions, it has become a general strong chelating agent. In the past, the research on EDTA chelate and chelation mainly focused on three aspects 1. The most stable metal chelates of EDTA are transition elements and rare earth elements.   2. It is a group of vegetative compounds with medium complexing strength, such as alkaline earth metal complexes. Because it is difficult for common reagents to realize the complexation of alkali metals, EDTA has attracted special attention;   3. The affinity of EDTA to protons was studied through the sequence of EDTA itself and its co alkali metal salt.   Edta-k Ψ is a kind of amino polycarboxylic acid, calcium chelating agent, which has a great affinity for calcium in blood. It can effectively chelate calcium in blood samples, chelate calcium or remove the calcium reaction site. The decrease of calcium content will block and terminate the endogenous or exogenous coagulation process, so as to prevent the coagulation of hemostatic fluid samples. Every 0.8 mg can anticoagulate 1 ml of blood. It can not be used for the determination of Ca, Na and N in plasma. It is also suitable for anticoagulation. Edta-k Ψ can also complex some ions in plasma to make some proteins or nucleic acids more stable, but the interference of chromium complex formation on samples and experiments should be considered.   Edta-k Ψ is suitable for general hematological examination, especially for platelet count. Because it affects platelet aggregation and phagocytic function of blood cells, it is not suitable for coagulation and platelet function examination. It is also not suitable for determination of Ca +, K +, Na +, Fe +, alkaline phosphatase, creatine kinase and leucine aminopeptidase and PCR test.   Additives for vacuum blood collection: the additives for vacuum blood collection are edta-k2 aqueous solution, and 4mg edta-k Ψ is needed for anticoagulation of 2ml blood.   Because the concentration is small, in order not to dilute the blood, 20 μ l of water solution containing 200 g / L edta-k Ψ is usually preset in each blood collection vessel. Because the blood collection vessel is valid for two years, when the use environment changes slightly, such as the temperature changes, the water is easy to evaporate to the tube wall (especially the water in the solvent of plastic pet tube can seep through the tube wall and leak out), resulting in tube leakage Edta-k Ψ crystallizes quickly in the blood sample. When collecting blood, it is required that edta-k Ψ be reversed for at least 8 times, so that the crystallized edta-k Ψ can be fully dissolved and mixed in the blood. If the action is a little bigger, the red blood cells will be destroyed and hemolyzed, and the platelets will be aggregated, adhered and broken.

Luminol, the luminescent substrate of horseradish peroxidase HRP, is chemically named 3-aminophthalic acid hydrazide, and sometimes also contains isoluminol and its derivatives such as ABEI, ITCI, etc., which are the reagents of this type of reagent Collectively. The synthesis process of this kind of reagent directly affects its luminescence performance, which in turn affects the detection result.   The synthesis process of luminol, isoluminol and its derivatives are all based on 3-aminophthalic hydrazide. The synthesis steps are divided into three steps. Here is a brief introduction to their synthesis trilogy:   1. Synthesis of 3-nitrophthalic acid   Luminol and isoluminol are both prepared by the reaction of nitrophthalic acid and hydrazine, and it is an important raw material for the synthesis process. Raw materials can be purchased directly, the cost will be higher, or they can be produced on their own. Mix 12 mL of concentrated sulfuric acid and 12 g of phthalic anhydride and heat, slowly add 10 mL of fuming nitric acid dropwise, and control the temperature at 100-110°C.   After the reaction is completed, it is cooled to obtain the product 3-nitrophthalic acid and the by-product 4-nitrophthalic acid. Using different water solubility, add water and filter to obtain the crude 3-nitrophthalic acid solid, and then use water for the solid Recrystallize to obtain the product.     Three steps of luminol synthesis   2. Synthesis of 3-nitrophthalic hydrazide   Put 1.3 g of 3-nitrophthalic acid and 2 mL of 10% hydrazine hydrate in a 100 mL two-necked flask, heat to dissolve, add 4 mL of triethylene glycol, fix the two-necked flask, add zeolite, The catheter connects the flask to the water pump through a safety bottle. Turn on the water pump and heat the flask to maintain the temperature at 210-220°C. After the reaction is complete, stop heating and pumping. Cool to 100°C, heat water, cool to room temperature and filter, collect light yellow crystals to obtain 3-nitrophthalic acid hydrazide.   3. Synthesis of luminol 3-aminophthalic hydrazide   The product from the previous step was transferred to a beaker, and sodium hydroxide solution was added to dissolve it. Add 4 g of sodium dithionite dihydrate, heat and stir, and keep boiling for 5 minutes. After a little cooling, 2.6 mL of glacial acetic acid was added, and the mixture was cooled to room temperature in a cold water bath to precipitate light yellow crystals, which were washed with suction and water for three times to obtain the final product luminol.   The above is the synthesis steps of luminol. Similarly, the by-product 4-nitrophthalic acid can be made into isoluminol, or the synthesis of isoluminol derivatives can be continued. The luminescent substrates currently synthesized by Desheng include luminol, isoluminol, and acridinium ester, a direct chemiluminescence reagent.

Tris base, cas77-86-1, also known as tromethamine, is a common reagent, which is widely used in industrial synthesis, biochemical detection and biopharmaceutical fields. In addition, Tris can also be used to prepare gold nanoparticles. Tris (hydroxymethyl) aminomethane is widely used in biochemistry and molecular biology experiments as a common raw material for buffer preparation. Tris is also an intermediate for the preparation of surfactants, vulcanization accelerators and some drugs. Because it has three equal hydroxyl groups, it can also be used as a good reducing agent. In the alkaline condition of sodium hydroxide, it can reduce chloroauric acid solution to prepare stable gold nanoparticles. This method is non-toxic and pollution-free, and belongs to green reduction method. At present, the classical synthesis methods of gold nanoparticles are sodium citrate reduction method, phase transfer method and seed growth method. These methods are the easiest to modify the surface of gold nanoparticles, but the preparation and modification of these methods have certain toxicity. In order to reduce the toxicity of gold nanoparticles to organisms in experiments and make them better used in biomedical field, researchers have been continuously developing new green reduction methods in recent years. For the first time, Tris was used as a reducing agent to reduce chloroauric acid solution under alkaline condition by ultrasound without adding other stabilizers. The environmentally friendly and biocompatible gold nanoparticles were synthesized. Gold nanoparticles with different sizes can be prepared by adjusting the experimental conditions. Compared with other green synthesis methods, the experimental conditions are more mild and the operation is simple. This provides a new research idea and theoretical basis for the synthesis of green, pollution-free, low toxicity, low cost and high biocompatibility gold nanoparticles. Since 2005, Desheng has developed and produced biological buffers, blood collection additives, color reagents and chemiluminescence reagents. The biological buffers include Tris, HEPES, caps, mops, etc. Desheng has always been adhering to the concept of quality first, products from the selection of raw materials to production and packaging layer upon layer, only to provide customers with quality products, do not forget the original intention can Zhiyuan.

In the field of in vitro diagnostics, enzyme colorimetry is a common method for quantitative or qualitative testing of target components, and it is widely used in China, such as the detection method of the color reaction of the enzyme HRP catalyzed by the chromogenic substrate TOOS in the Trinder reaction. Because of the participation of enzymes, it is very valuable to improve the stability of the enzyme activity color substrate.   Some reaction products with high molar absorbance chromogenic substrates, such as TOOS, TOPS, etc., can be used in wet chemical methods as well as dry chemical methods: the required reaction reagents (TOOS, 4-AAP) and the required enzymes (HRP) Etc.) It is fixed on the membrane carrier, and the sample is added dropwise to generate H2O2 and then release new ecological oxygen, oxidize the color substrate, and indirectly determine the target component through the amount of the reaction product. Enzymes are highly specific and highly efficient in catalysis. However, they have poor stability under the influence of temperature, pressure, and light in dry chemical methods. In wet chemical methods, enzymes are easily inactivated when they are in a liquid state or at low concentrations.   Chromogenic substrate TOOS powder   On the other hand, most chromogenic substrates, such as TOOS, MAOS, TMB, etc., are also easily oxidized slowly, so their solutions cannot be exposed to the air for a long time. There are many ways to improve the stability of biologically active enzymes and chromogenic substrates:   1. Adding enzyme solution protective agent can make the activity of various enzymes such as ALT, AST, LDH, ALP, CK in aqueous solution or serum matrix stable for 2 weeks at room temperature, but the effect on dry chemical test paper is not significant.   2. The color-developing substrate stabilization method uses surfactants and flavonoid pigment substances with an alkyl group with 8 to 16 carbon atoms, but the formula is complicated, the reagents are difficult to buy, and the protective agent interferes with the test results.   3. There is a protective agent that is more reducible than the color-developing substrate, but the added protective agent contains primary amino groups and often causes non-specific reactions.   4. The use of azo dyes as stabilizers of the color-developing substrate has a good stabilizing effect and does not cause interference, but the maximum absorption wavelength of the dye is sometimes close to that of the color-developing agent, which makes the blank control a bit higher.   5. A protective agent for polymer and its composition, which can improve the stability of enzymes and chromogenic substrates. Applicable chromogenic substrates include TOOS, 4-AA, TOPS, MAOS, etc., suitable for HRP, CHO, etc. Enzyme, suitable for the detection of glucose, creatinine, uric acid, cholesterol, triglyceride and other indicators.   It can be seen that various existing protective agents for enzymes or chromogenic substrates, some of which are defective, such as high cost, biased detection, and only suitable for wet chemical methods, etc., thus improving the stability of enzymes and chromogenic substrates The method needs further research. Desheng is a manufacturer of chromogenic substrates and enzymes. It is recommended that you pay more attention to the use of chromogenic substrates and enzymes.

When we use the good's buffer, we always inadvertently confuse the HEPES buffer and pipes in the good's buffer, thinking that they are the same, which makes it impossible to distinguish them very accurately. In fact, there are similarities between them, but there are also many different characteristics.   Especially in the process of our experiment, a little difference may lead to the failure of the experiment. So we need to know what buffer is and what it does? In order to distinguish between HEPES and pipes in buffer, what is the difference between them? What should we pay attention to when using?   Buffer solution is a kind of special buffer system for life science research. In biochemical experiments, buffer solution plays an indispensable role. It can resist the influence of a small amount of strong acids and bases, and maintain the pH value closest to the physiological environment for the system. HEPES and pipes buffers are commonly used in biological experiments.   Product packaging   The pH buffer range of HEPES is 6.8-8.2, which is a kind of zwitterionic biological buffer. It is soluble in water and does not form stable complexes with metal ions. In most cases, it does not interfere with biochemical processes. It can be widely used in a variety of biochemical reactions and used as a buffer reagent in some cell culture media.   HEPES is commonly used in cell culture media of various types of organisms; in protein research, it is often used as the component and eluent of binding buffer in cation exchange chromatography; in DNA research, it is used as the buffer of calcium phosphate and DNA sediment formation system, AFM and electroporation experiment.   In addition, HEPES interferes with the reaction between DNA and restriction enzyme and is not suitable for Lowry's method. HEPES buffer is often used in the research of organelles and pH sensitive proteins and enzymes, as well as in biochemical diagnostic kits, DNA / RNA extraction kits and PCR diagnostic kits. It is a hydrogen ion buffer, which can control the constant pH range for a long time. When the final concentration is 10-50 mmol / L and the culture medium contains 20 mmol / L HEPES, the buffer capacity can be achieved.   The pH buffer range of pipes is 6.1-7.5, insoluble in water and soluble in NaOH solution. Different from buffers containing bis (2-hydroxyethyl) amino groups (such as bis Tris, bicine), pipes can not form stable complexes with most metal ions, so it is suitable for buffers containing metal ions.   According to previous studies, PIPES can be used to purify tubulin by using cellulose phosphate chromatography, and to purify recombinant GTP binding protein ARF1 and ARF2 by gel filtration as a buffer to crystallize ketoenzyme from E. coli. In addition, due to the formation of free radicals, pipe is not suitable for redox system. In cation exchange chromatography, low concentration of pipes buffer should be used because of its relatively high ionic strength and concentration dependent pKa value.   It can be seen that neither pipes nor HEPES can form stable complexes with metal ions, which is suitable for the solution containing metal ions. However, there are some differences between them. In terms of solubility, pipe is insoluble in water, while HEPES has good water solubility. In terms of buffer range, pipe is acidic to neutral, and HEPES is neutral to alkaline. This is mainly due to the structural differences between them. Pipe has two sulfonic groups, and HEPES contains one sulfonic group and hydroxyl group.   In addition, pipes and HEPES have some limitations in the application of some systems. Therefore, when we choose the above buffers, we need to consider the suitability of the experimental system and the difference of their properties.   We should learn to distinguish and understand the similarities and differences in these reagents, so as to better promote the R & D and production of our different products. Desheng consistently adheres to this kind of subtle difference, so as to continuously develop and produce better products.

The detection of the new coronavirus is mainly through PCR amplification of viral nucleic acid. However, in addition to nucleic acid detection, various research and development institutions have also successively developed methods for virus antibody detection and virus specific protein detection. Recently, Shenzhen University has successfully developed a chemiluminescence new crown detection kit, and the test results can be obtained in 22 minutes! On the evening of February 10, the world's first single-person chemiluminescence detection kit for novel coronavirus IgM and IgG antibodies jointly developed by Shenzhen University and multiple scientific research institutions announced its success. Chemiluminescence new crown detection kit results in 22 minutes According to the news, a single copy of the new coronavirus IgM and IgG antibody chemiluminescence detection kit has completed the detection of 30 new coronavirus pneumonia patients in the local hospital. Chemiluminescence antibody detection is different from virus nucleic acid detection. This kit detects the new coronavirus-specific IgM/IgG antibody in the blood of the infected person, and can complete the rapid diagnosis of new coronavirus infection in 22 minutes. The test kit developed this time is to detect the antibodies produced by the patient's immune response to the infected virus, not the virus itself (such as viral nucleic acid). This also avoids the risk of secondary infection caused by virus samples for the inspectors and the inspection environment. Viral nucleic acid detection: Viral nucleic acid detection is to place a virus sample in a sampling tube with a virus transport media, and transfer it to a nucleic acid testing laboratory to perform RNA reverse transcription polymerase chain reaction RT-PCR for detection. Whether the preservation solution for processing virus samples is inactivated or non-inactivated, the nucleic acid RNA of the virus can be retained, and the object of detection is RNA. Virus antibody detection: The object of antibody testing is not a virus sample, but a blood sample (or other body fluid) of the subject. The sampling method is through blood collection tubes or other methods. This is the use of the human body’s immune response mechanism. After a person is infected with the new coronavirus, specific antibodies will be produced in the body. As long as the specific antibodies are detected, it can indicate that they have been infected with the new coronavirus. In the process of fighting against the common enemy of mankind, the new crown, various groups and individuals in related fields spare no effort. Desheng provides relevant products for the market including virus preservation solutions, chemiluminescence reagents, buffers, etc., to fully assist in the research and development of new crown detection technologies.

Carbomer has a wide range of uses, including: home care, industrial and detergent, personal care products / cosmetics, pharmaceutical excipients, solid fuel adhesives and alkaline batteries. Carbopol 980 is a white loose powder, it has good thickening performance, high transparency, high viscosity, strong suspension ability, short rheological Carbopol of cosolvent system, and excellent suspension stability. The main characteristics are swelling and slightly acidic. Carbomer white loose powder From these aspects, we can see what kind of existence it is in our life. But for such a widely used raw material, most of our country depends on foreign imports. Originally, the balance has been maintained in this way, but something unexpected happened. An epidemic at the end of the year not only disrupted our lives, but also affected our industry - carbomer is out of stock, to be exact, the products produced by carbomer are out of stock. How can we produce products without raw materials? It's hard to cook without rice! The Internet and the phone are full of people asking about carbomer raw materials. Our Desheng company stepped forward at such an emergency. Since returning to work, we have increased manpower and material resources, and worked overtime every day to produce the raw material of carbomer. However, there are many problems. First of all, the equipment is not perfect. The company has invested a lot of money to introduce new equipment, but it has to be installed in the state of shutdown. The second site is not enough, the company leaders regardless of hard work, go all the way to find a suitable production site. The third is the shortage of manpower. The company has stepped up its recruitment efforts to recruit people with relevant work experience during this period and ensure the smooth progress of the production period. This is only the problem encountered in the early stage, and there are countless problems encountered in the follow-up. But Desheng did not give up, even in such difficult conditions, in the trust of customers, we still insist. Huangtian pays tribute to those who want to succeed in the R & D of capom of Desheng. But at present, it can only be produced in small quantities. Please trust our customers all the time. Don't worry, the victory is not far away from us. We Desheng will also adhere to our tenet: morality oriented, honesty first, quality first, technology leading. Our service philosophy: the problems that belong to us, we do not hesitate to undertake; the problems that do not belong to us, we try our best to help customers solve; the problems that can not distinguish responsibilities, belong to us. With such a tenet and service concept, why don't we worry about big things.

We often see on TV that when the police find evidence of crime, the ground is clean. How do they know where there is blood? And through what to test the bloodstain? We have to mention our little detective Luminol.   Luminol, also known as luminol, is a kind of chemiluminescent molecule. It is easily soluble in lye, soluble in dilute acid, almost insoluble in water, and hardly soluble in alcohol. The suitable fluorescence wavelength was 425nm   (chemiluminescence was detected in 60 mm K2S2O8, 100 mm K2CO3, pH 11.5). In the presence of hydrogen peroxide, it can be transformed into excited state aminophthalic acid, which emits strong fluorescence. It is a kind of blood that can not be observed by naked eyes at the scene of crime, and can show a very small amount of blood form (occult blood reaction). The chemical name is 5-amino-benzoylhydrazide.   At room temperature is a blue crystal or pale yellow powder, is a relatively stable synthetic organic compounds. The chemical formula is c8h7n3o2. At the same time, luminol is a kind of strong acid, which can stimulate eyes, skin and respiratory tract. Hemoglobin contains iron, which can catalyze the decomposition of hydrogen peroxide, turning hydrogen peroxide into water and monooxygen, which then oxidizes luminol to make it glow. Therefore, luminol is widely used in criminal investigation, bioengineering, chemical tracing and other fields. In forensic medicine, luminol reagent uses the reagent to identify blood. Even if the blood stains are wiped, the heme in the blood will still remain. When luminol reagent is sprayed on the heme, it will oxidize with reactive oxygen species and release blue purple fluorescence. It is an organic substance used to identify blood. In biology, luminol is used to detect the presence of copper, iron and other substances in cells.   But it also has some disadvantages 1. Luminol fluoresces in the presence of iron, ferroalloys, horseradish or some bleaching agents. So if the crime scene is completely bleached, luminol's fluorescence will strongly mask the presence of any blood stains.   2. Luminol can detect a small amount of blood in animal blood and urine, so if there is urine or animal blood in the room to be tested, the test results will be biased.   3. Luminol reacts with excreta and emits the same light as blood.   4. Luminol may interfere with other tests, but luminol does not interfere with DNA extraction.   5. Luminol needs to be used in a dark environment, otherwise the fluorescence is difficult to identify.   6. Luminol luminescent time is limited, we should seize the time to take photos and record.   How can we avoid interference 1、 Let the site dry for a few days, the interference of bleach will disappear, and the bloodstain can make luminol glow even after many years.   2、 Use a compound that can inhibit the interference of hypochlorite. It's obvious that antioxidants should not be used because they will inhibit the reaction of blood stains with luminol. According to the chemical structure of hypochlorous acid, such as the chlorine atom it contains, suitable inhibitors have been found. The safe way is to use luminol luminescence method to detect the suspected blood substance, and then use other methods to determine that it is indeed blood.   Moreover, it was found that after the bloodstain was treated with luminol, the DNA contained in it was not destroyed, and it could be extracted for identification.   Through the above, it is not difficult to guess how those bloodstains were detected.   Since its establishment in 2005, Desheng company has been committed to the development and production of luminescent reagents, blood collection additives, biological buffers, etc., with rich experience.

Now more and more women pay attention to skin care, and even more and more men begin to pay attention, because a good skin will give people a clean and comfortable impression. On the market, mild hydrated and non irritating cosmetics are more and more popular with the public. The advertising slogan of major brands of cosmetics is "add safely and non irritating", which makes the majority of consumers and manufacturers pay attention to the added ingredients of cosmetics, and HEPES and Tris become popular additives.   HEPES buffer (7365-45-9) and tris (77-86-1) are the ingredients with EWG green certification, which are safe and mild. The certification level of tromethamine is 1-2, and that of HEPES is 1. This article will introduce the role of HEPES and Tris in cosmetics.   HEPES and Tris are important buffers widely used. Tris is weakly alkaline, PKA is 8.06 at 25 ℃, pH buffer range: 7.0-9.0, widely used in biochemistry, molecular biology, coatings and other fields.   HEPES, 4-hydroxyethyl piperazine ethanesulfonic acid, is a kind of zwitterionic buffer, belonging to good's buffer, with pH buffer range of 6.8-8.2. HEPES buffer is often used in the research of organelles and pH sensitive proteins and enzymes, as well as in biochemical diagnostic kits, DNA / RNA extraction kits and PCR diagnostic kits.   As a component of cosmetics, HEPES and Tris have different functions and advantages. The most common function of Tris in cosmetics is to adjust pH value (pH value). It can also be used as a neutralizing agent to neutralize Thickener (carbomer), so as to reduce the sticky feeling, improve the respiratory efficiency of skin cells, and prevent pore blockage.   In addition, Tris can be used as an odor regulator in cosmetics containing amine salts to regulate the odor of amine produced by rubbing when applying cosmetics, so as to avoid the release of any residual or persistent odor.   HEPES has the advantages of safety to human body, non-toxic, good physiological compatibility and stable chemical performance. From the perspective of EWG certification level, HEPES is safer than Tris. HEPES can stabilize the pH range of skin care products for a long time, better maintain the activity of microbial fermentation products extract, and make the anti-aging effect of products last for a long time, so it is often used as a stabilizer and activator in cosmetics.   HEPES is also a common penetration enhancer, which can promote the transdermal absorption of various functional components in cosmetics. Compared with azone penetration enhancers, HEPES has the characteristics of short onset time, less dosage and high penetration rate. In addition, in some famous cosmetics such as L'Oreal and Lan-come, HEPES is mainly used as a peeling agent to soften cutin and promote the metabolism of skin cells.   EWG certification has become an important standard for people to choose safe cosmetics. EWG safety level is 1-10, of which 0-2 is green safety level, 3-6 is yellow, representing medium hazard, 7-9 is red, representing high hazard. The EWG certification of HEPES and Tris belong to the green level, reaching the international standard, meeting the people's demand for "safe and natural" cosmetic ingredients.   Desheng has more than ten years of experience in the production and development of biological buffers, blood collection additives and in vitro diagnostic reagents, and insists on providing high-quality products for customers. HEPES and Tris are popular products of the company. Can also provide customers with neutralizing thickener carbomer.

Recently, a friend just bought a new house and was worried about the decoration. Because there are old people and children at home, we are very careful in choosing materials. Later, when I heard about this, I directly recommended him to buy water-based coatings containing caps, because my own company developed and produced caps products, from which I learned its advantages in coatings. In addition, people's awareness of health and environmental protection is becoming more and more intense. This trend forces industry giants to compete to develop new environmental protection coatings. Caps buffer (3 - (cyclohexylamino) - 1-propane sulfonic acid) stands out in this competition and becomes the leader of new environmental protection coatings. Let me talk about why we should choose water-based coatings with caps. What role does caps play?   Caps, 3 - (cyclohexylamine) - 1-propanesulfonic acid, cas1135-40-6, is a member of good's buffer. Caps has a wide range of uses. The properties of 3-cyclohexylaminopropane sulfonic acid (CAPS) are relatively stable. The pKa value is 10.4 at 25 ° C, and the pH buffer range is 9.7-11.1.   Product packaging   In the 1960s, a kind of polyurethane coating began to emerge. In most application fields, water dispersible polyisocyanate was modified by polyether to achieve non-ionic hydrophilic. Although this kind of hydrophilic polyisocyanate has been widely recognized in the market, it still has some defects, such as high viscosity. In the process of use, it needs to apply a large shear force to blend it into the water medium evenly. Especially when it is used as the crosslinking agent of waterborne two-component polyurethane coatings, it needs a high polyether content to ensure sufficient dispersion, which is very important It results in a long drying time and gives the coating lasting hydrophilicity.   In order to avoid these shortcomings, researchers have tried to prepare water dispersible polyisocyanates by adding ionic groups to hydrophilic modification, including carboxyl groups, sulfuric acid groups, hydroxyl groups, and hydroxysulfonic acid groups. However, there are still certain defects, such as carboxyl modified polymers, which are easy to gel, and the color of products modified by hydroxysulfonic acid is obviously yellow. Later, Bayer company reported the caps modified polyisocyanate in its patent cn1429240a. It was found that the caps modified polyisocyanate could be finely dispersed in water and the product was stable in storage. Aliphatic polyisocyanates reacted with caps under mild conditions and in the presence of tertiary amine neutralizer to obtain Sulfonate Modified polyisocyanate crosslinker   CAPS modified polyisocyanate has good storage stability. Even if it contains less sulfonate base group, it can also get very good emulsion in water. There are many market-oriented products, which can be used in a variety of environmentally friendly high-quality waterborne two-component polyurethane coatings. These coatings can fully achieve the performance of solvent based coatings in terms of drying, curing and chemical resistance. If the new regulations require further reduction of VOC, the amount of these crosslinking agents will increase greatly in the future, because compared with solvent based coatings, they will not lead to the deterioration of film quality. By using hydrophilic modified polyisocyanate and simple manual stirring, the uniform mixture of base material and crosslinking agent without cosolvent can be obtained.   As mentioned above, the water-based coatings market led by caps will seize the market share at a rapid speed. The application of caps in the field of biochemical industry is also rising step by step with the rapid development of the medical industry.   Caps developed and produced by Desheng company is not only used in new coatings, but also used in biochemical diagnostic kits, DNA / RNA extraction kits and PCR diagnostic kits. Customers in need are welcome to contact us.

Under the influence of the epidemic, a large number of Virus Transport Media also appeared in the public view. But our understanding of it is only limited to know that it is collecting virus for detection, but what is its own ability? Why is it also called inactivated Virus Transport Media? We can only understand according to the literal meaning, that is to kill the live virus and do research after preservation. But is it really that simple? It's just the idea of a lot of people who don't understand. First, let's see why it's called inactivation?   What is inactivation? Inactivation is a method of killing viruses and bacteria by physical or chemical means without damaging their useful antigens.   Inactivated Virus Transport Media: it is a colorless transparent liquid, suitable for viruses, New Coronavirus, influenza, avian influenza, hand foot and mouth urticaria and other viruses. It destroys the structure of virus protein, and the protein has no physiological activity, so it loses the ability of infection, pathogenicity and reproduction. However, conventional inactivation does not affect the primary structure of virus protein, which means that the sequence of virus protein has not changed.   The inactivated samples can be matched with the corresponding New Coronavirus RNA extraction kit, M32/M96 nucleic acid extractor and other rapid extraction of virus nucleic acid, and New Coronavirus PCR detection kit to achieve rapid detection, specificity sensitivity is not affected. Applicable kit methods: fluorescent PCR, combined probe anchored polymerization sequencing, isothermal amplification chip, magnetic particle chemiluminescence, colloidal gold.   So the inactivated virus has antigenicity, but loses infectivity. This is actually how many vaccines are made.   The inactivated virus lost its infective activity, but still had fusion activity. It is an inducer for cell fusion in animal cell engineering. Inactivated Virus Transport Media has the following advantages: 1. Inactivate the virus to avoid cross infection of centralized sampling 2. Inactivate the virus and reduce the difficulty of preservation and transportation 3. The samples lose their infectivity and protect the testing personnel 4. It is widely used in PCR laboratory   In addition to the above inactivated Virus Transport Media, Desheng company also developed and produced non inactivated Virus Transport Media, which contains Hanks solution base, gentamicin, fungal antibiotics, BSA (V), cryoprotectants, biological buffers and amino acids. Non inactivated Virus Transport Media is usually used for the collection and transportation of clinical influenza, avian influenza (such as h7n9), hand foot mouth disease, measles and other virus samples, as well as Mycoplasma, Ureaplasma, chlamydia and other samples.

As a new Trinder's reagent, Maos reagent plays an important role in it. Its Chinese name is n-ethyl-n - (2-hydroxy-3-sulfopropyl) - 3,5-dimethylaniline sodium salt monohydrate, which is a white powder and soluble in water, Sensitive to light and humidity, CAS No.: 82692-97-5, Maos product produced by Desheng, purity ≥ 99%, good water solubility, stable process, can ensure the appearance of pure white crystal powder.   The new Trinder's reagent is a highly water-soluble aniline derivative, which is widely used in diagnostic detection and biochemical tests. In the colorimetric determination of hydrogen peroxide activity, it has several advantages over conventional chromogenic reagents.     The new Trinder's reagent is stable enough to be used in both solution and test line detection system. In the presence of hydrogen peroxide and peroxidase, the new Trinder's reagent formed very stable purple or blue dyes in the oxidative coupling reaction with 4-aminoantipyrine (4-AA) or 3-methylbenzothiazolylsulfonylhydrazone (MBTH). The molar absorptivity of the dye coupled with MBTH is 1.5-2 times higher than that of the dye coupled with 4-AA; however, 4-AA solution is more stable than MBTH solution. The substrate is enzymatically oxidized by its oxidase to produce hydrogen peroxide. The concentration of hydrogen peroxide corresponds to the substrate concentration.   Therefore, the amount of substrate can be determined by the color reaction of oxidative coupling reaction. Glucose, alcohol, acyl coenzyme A and cholesterol can be used to detect those substrates coupled with the new Trinder's reagent and 4-AA. There are 10 kinds of new Trinder's reagents, and the application of Maos is also very important. For specific substrates, it is necessary to test different kinds of new Trinder's reagents to develop the best detection system.   The new Trinder's reagent Maos is one of Desheng's main products. Desheng's products have passed the strict quality inspection and passed the national ISO9001 quality management system certification. Not only the quality is good, but our price is also very favorable compared with many other manufacturers. If you have the intention to purchase, we can provide you with a small sample for trial, use well and then buy back. The specific situation is as follows Please contact us