China Wuhan Desheng Biochemical Technology Co., Ltd Company News

The history of immunology began with the study of Microbiology, established in the 18th century, and entered the classic development period from the 19th century to the mid-20th century. During this period, people's understanding of immune function entered the period of scientific experiment from the observation of human body phenomenon. From the early to the middle of the 20th century, it entered the period of modern immunology. From the middle of the 20th century, it really entered the period of modern immunology. The detection of modern immunology has gone through the following processes. The specific reaction of antigen and antibody is used to detect, and isotope, enzyme and chemiluminescence are used to amplify and display the detection signal. It is often used to detect protein, hormone and other trace substances. Immunodiagnosis plays a very important role in clinical diagnosis. The common immunotechnologies include radioimmunoassay, enzyme-linked immunosorbent assay, chemiluminescence, electrochemiluminescence and chemiluminescence of magnetic nanoparticles. 1. Principles of radioimmunoassay The radiolabeled antigen and unlabeled antigen (to be tested) were competitively combined with insufficient specific antibodies, and the amount of unlabeled antigen was obtained by separating and measuring the radioactivity after reaction. 2. Principle of enzyme linked immunosorbent assay Referred to as ELISA, its center is to let the antibody and enzyme complex binding, and then through the color to detect. The antigen or antibody can be bound to the surface of a solid carrier and keep its immune activity. To make an antigen or antibody linked with an enzyme to form an enzyme-linked antigen or antibody. The enzyme-linked antigen or antibody retains both its immune activity and the activity of the enzyme. Because of the high catalytic frequency of enzyme, it can greatly enlarge the reaction effect and make the determination method reach high sensitivity. ELISA can be used to determine antigen and antibody. 3. Principle of chemiluminescence Technology The free energy released by the chemical reaction is used to excite the intermediate and make it return to the ground state from the excited state. When the intermediate returns to the ground state from the excited state, it will release equal level photons. Chemiluminescence has the specificity of fluorescence, at the same time, it does not need to excite luminescence, which avoids the influence of stray light of excitation light in fluorescence analysis, so as to improve the sensitivity, and avoid the environmental pollution and health hazards caused by radiation analysis. It is a very excellent quantitative analysis method. 4. Principle of electrochemiluminescence Technology Electrochemiluminescence (ECL) is the result of the participation of electric field in chemiluminescence, which refers to the electrochemical reaction by applying a certain voltage: the TPA on the electrode surface releases electrons, and then releases protons to become free radical TPA *, at the same time, the divalent Ru (bpy) 3] 2 + releases electrons to become trivalent Ru (bpy) 3 + 3 +. There are still divalent Ru (bpy) 3] 2 + and tPA in the reaction system, so that the electrochemical reaction on the electrode surface can continue. In this way, the whole reaction process can be continuously cycled, and the detection signal is continuously amplified, so the detection sensitivity is greatly improved, so the ECL determination has the characteristics of high sensitivity. 5. Principle of chemiluminescence immunoassay with magnetic particles It is a new analytical method that combines magnetic separation technology, chemiluminescence technology and immunoassay technology. The technology makes full use of the rapidity and automaticity of magnetic separation technology, the high sensitivity of chemiluminescence technology and the specificity of immunoassay. It plays an irreplaceable role in the field of biological analysis. At present, magnetic particle chemiluminescence immunoassay has been used in tubular chemiluminescence immunoassay and electrochemiluminescence immunoassay.

Taps name n-tri (hydroxymethyl) methyl-3-aminopropane sulfonic acid, CAS No. 29915-38-6, molecular formula c7h17no6s, from the appearance, belongs to white crystal, its content is very high, more than 99%. Trimethylolmethylamino propanesulfonic acid (TAPS buffer) is also a kind of biological buffer. It has good water solubility. The concentration is usually 25g / 50ml. The solution is colorless and transparent, and very clear. The pH value is between 7.7 and 9.1, and the pKa value is 8.4. Taps is a kind of zwitterionic buffer widely used in biochemistry and molecular biology. It can be used not only as a buffer system in DNA screening system, but also as a buffer component of RNA sample; It can also be used as an important pH stabilizing reagent, which is usually mixed with weak acid and its conjugated base to obtain appropriate pH value. He is used for electron transfer and phosphorylation of chloroplast thin layer preparation; During the freeze-drying process, oxyhemoglobin can be protected from oxidation to methemoglobin; It can also be used as a background electrolyte for protein microanalysis by capillary zone electrophoresis. In biochemical experiment projects, taps reacts with most organisms under neutral conditions. The pH value should be between 6 and 8, and the effective buffer range of buffer should also be between 6 and 8. Moreover, it is necessary to ensure that the pH form of buffer reagent cannot chelate with some metal chemical ions. Taps, a buffer used in biochemical detection and molecular diagnosis, has high requirements for reagent purity and impurity ion content. In the field of clinical diagnosis, taps is also commonly used as a biological buffer. It is usually used in some biochemical diagnostic kits, PCR diagnostic kits and DNA / RNA extraction kits. Desheng is skilled in technology. Taps buffer is made of high purity and high quality taps. After strict filtration, sterilization and quality testing, it can be directly added to the culture medium. It should be noted that taps buffer, buffer range is ph7.7-9.1, PKA (ion concentration set) is 8.4. Taps buffer is directly added to the sterile medium or added to the instrument to filter and sterilize the medium. Desheng technology has done a lot of research and improvement in this aspect, and many kinds of biological buffers produced by the company have been recognized by a large number of biochemical testing enterprises and pharmaceutical equipment enterprises.

Luminescent immunodiagnostic reagents are widely used in the fields of tumor markers, endocrine function, hormones, infectious diseases and other medical diagnosis, which is of great significance in disease diagnosis and adjuvant treatment. At present, there are mainly chemiluminescence (CLIA), electrochemiluminescence (ecli) and time-resolved chemiluminescence (TRFIA) methods. Each method has its own advantages and disadvantages. Below, Desheng will introduce the principles, advantages and disadvantages of these methods. Chemiluminescence method It mainly refers to the phenomenon that the luminescent agent of the substance participating in the chemical change radiates the absorbed chemical energy to produce light, mainly including direct chemiluminescence and enzymatic chemiluminescence. The most common direct chemiluminescence system is acridine ester / hydrogen peroxide system, which has relatively high sensitivity, but at the same time has the disadvantage of short luminescence time. Enzymatic chemiluminescence mainly includes horseradish peroxidase (HRP) - luminol system, alkaline phosphatase (ALP) - amppd system and so on. Its advantage is that the luminous signal is strong and stable, and the luminous time is long, but the working curve may drift with time. Desheng can provide luminol, isoluminol, acridine ester and other chemiluminescence substrates. Electrochemiluminescence Electrochemiluminescence is a combination of electrochemistry and chemiluminescence. It refers to the phenomenon that the excited state is generated by the electron transfer reaction on the electrode surface, and when it returns to the ground state, it produces light radiation. Electrochemiluminescence has two processes: electrochemical reaction and chemiluminescence reaction. Tripropylamine was used as electron donor and ruthenium tripyridine was used to label antibody (antigen). Compared with photoluminescence analysis, electrochemiluminescence is electrically activated, without excitation light source. Its luminescence signal is stable and the luminescence time is long, which effectively avoids the interference caused by stray light and impure light source, and greatly increases the sensitivity of analysis. But at the same time, there are some disadvantages, such as complex measurement method, high maintenance cost. Time resolved fluorescence Time resolved fluoroimmunoassay is a microanalysis method developed in recent ten years. The principle is to use trivalent rare earth ions (such as EU, EU, SM, SM, Te, TB, Dy) as tracers to label proteins, peptides, hormones, antibodies, nucleic acid probes or bioactive cells. After the reaction system (such as antigen antibody immune reaction, biotin avidin reaction, nucleic acid probe hybridization reaction, target cell and effector cell killing reaction, etc.) takes place, the target cells can be labeled, The fluorescence intensity of the final product was determined by time-resolved fluorescence immunoassay to determine the concentration of the substance in the reaction system. Time resolved chemiluminescence has similar sensitivity to electrochemiluminescence and is more stable. However, the compatibility of the instrument is poor, the price is expensive, the operation is relatively complicated, and the requirements for reagents, water quality and environment in the production process are high.

Do you know? In the organizational structure of Desheng Technology, there is an important department that runs through the management of the entire company-the Quality Department. As a whole industry chain company integrating production, R&D, and sales, Desun Technology has always put quality management at the top of daily management. From R&D to production to sales, every step is a quality output management process. . On April 14, 2021, Desheng Technology held this year's Quality Cultural Activity Festival. In this event, Desheng’s friends demonstrated the importance of quality through a variety of activities on the spot. Quality work has only a starting point and no end.   01 Two training sessions of "Quality Awareness" and "GMP Knowledge" Through the two trainings of "Quality Awareness" and "GMP Knowledge", each of Desheng Technology's small partners has a new understanding of "quality". The lecturer thoroughly explained the importance of quality management by citing examples from various aspects, and explained in a simple way. The scientific requirements of quality management and the logical theory were told to everyone. The atmosphere was enthusiastic, and everyone actively asked questions, and the emphasis on "quality" was deepened. The site was full of a strong quality culture atmosphere.   02Quality Awareness Mini Game Everyone actively participated in the game and improved their quality awareness through this game. In the connection game, we have established the concept that the next player is the customer. When chatting with customers, pay attention to the way of expression, have quality and content, and ensure that the words spoken are valuable, so that the customers can give us affirmation.   03Wonderful debate Understand that quality is closely related to our lives. A wonderful debate game further allowed everyone to understand the meaning of quality. Topic: Does high quality increase costs or reduce costs. Both the pros and the opponents used their own powerful logical abilities to prove their own views, and they were even fighting each other. The thoughts of the audience were completely brought into it, and everyone began to proactively think about whether high quality is to increase or reduce costs.   Desheng Technology has established a 360° total quality management system that runs through R&D, procurement, production and service, so that every step of the production process has strict control standards and traceable management. In the production process, the SOP of the product runs through each operation link, the key quality control points of the process are carefully controlled throughout the process, and the production procedures are strictly followed to provide customers with small batch differences and high stability diagnostic reagent raw materials.   Through the development of this quality cultural activity, we will guide everyone to pay attention to quality, cultivate good working habits, enhance quality awareness, and cultivate the concept of close integration of quality and personal development, and we must stick to it for a long time, strictly control product quality, and resolutely put an end to unqualified products Flowing into the market, this is the most valuable asset of Desheng's sustainable and stable development in the future!

A few years ago, scientists conducted biochemical experiments with insufficient buffers, which greatly limited the results of their research. These buffers exhibit high cytotoxicity and cannot support enzymatic activity throughout the process. Then, in 1966, a professional team designed a series of buffers (Caps, Hepes, Mops, etc.) specifically for biological research. These buffers have the following characteristics:     1. The pKa value of Good buffer should be between 6.0 and 8.0, because the optimal pH of most biological reactions is within this range.   2. Good buffer should have high water solubility, and its solubility in organic solvents should be minimal, so it should be retained in the aqueous medium of the biological system.   3. Good buffer should not penetrate the cell membrane. The buffer should not accumulate in the organelles. This may not apply to your specific experiment. Zwitterionic buffers will not penetrate cell membranes.   4. Good buffers should have the smallest salt effect, because if the biological system under study is adversely affected by salt, the ion buffer may cause problems.   5. The concentration of Good buffering agent, temperature and ion composition of the medium have the least influence on the buffering capacity (pKa).   6. The formation of complexes between metal ions and Good buffer will cause the release of protons, which will affect the pH of the system and may adversely affect the results of the experiment. Therefore, these ionic complexes should be soluble and their binding constants must be known. Buffers with low metal binding constants are suitable for studying metal-dependent enzymatic reactions. If your experimental design requires the use of metals, then you should choose a buffer that does not form a complex with that specific metal.   7. Good buffer should be stable and resistant to enzymatic and non-enzymatic degradation. And they should not interfere with enzyme substrates or similar enzyme substrates.   8. Good buffer should not absorb light in the visible or ultraviolet region of the spectrum to prevent interference in spectrophotometric measurement.   9. Their preparation and purification should be easy and cheap.   In summary, the characteristics of Good buffers in biological buffers are very many and obvious, and this has also led to Good buffers becoming popular on the market. Nowadays, when purchasing products, I want to find a manufacturer who can get preferential prices and professional technical support, but now there are not many professional manufacturers, and our company is one of the few manufacturers of biological buffers.     As a manufacturer specializing in the production of biological buffers, Hubei Xindesheng Materials Co., Ltd. provides a large number of high-quality Hepes, Caps, Mops and many other types of biological buffers. Our company can customize the product specifications and after-sales service according to customer needs, and we can provide professional testing services and packaging customization services to special customers. In any case, Desheng company must be the only one for you to buy biological buffers to select.

High-quality Tris buffer is an important part of electrophoresis. It allows current to pass through the sample while resisting changes in the pH value of the entire solution. The choice of buffer depends on the isoelectric point of the sample being analyzed. In DNA electrophoresis, the commonly used buffers are Tris-Acetate-EDTA and Tris-Borate-EDTA. In protein electrophoresis, SDS (sodium dodecyl sulfate) is usually used. These buffers help separate samples into readable gels. Depending on the sample, other buffers can help improve results or expand readings at specific molecular weights. Recently, I have obtained some knowledge about electrophoresis buffer through professional literature, and I want to share and discuss with you here. The role of Tris-acetate-EDTA and Tris-borate-EDTA in agarose gel electrophoresis: Tris is a strong base and boric acid is an acid. The combination of the two can keep the pH in the neutral range of 8 to 8.5. Under such alkaline conditions, DNA is protected and can be separated properly. EDTA plays an important role in this combination. EDTA is a chelating agent. It chelates the Mg2+ ions required by the DNAse enzyme as a cofactor. DNAse is an enzyme that cuts DNA into small fragments. Therefore, by adding EDTA, we can protect our DNA from enzymatic activity. In addition, the buffer will neutralize the charge of the water molecules. Under the action of electric current, water molecules decompose into H + and OH-. H + ions can react with the PO3- of DNA. Therefore, the negative charge of the buffer will neutralize the charge in the water and protect the DNA. Although Tris-Acetate-EDTA and Tris-Borate-EDTA have the same role in electrophoresis, they have their own advantages and disadvantages. Tris-acetate-EDT buffer can interfere with enzymatic reactions and protect DNA, while Tris-borate-EDTA buffer cannot. In summary, the use of Tris-acetate-EDTA and Tris-borate-EDTA derived from Tris buffer in electrophoresis is very important, and this is one of the reasons why Tris buffer is in short supply in today’s market. One. Last time now, it was very difficult to find a manufacturer specializing in the production of Tris, but here I would like to recommend our company, Hubei Xindesheng Materials Co., Ltd. Hubei Xindesheng Material Co., Ltd. specializes in the production of Tris, Hepes, Mops and other buffer products. Up to now, the company has been established for decades and has very rich experience in the development and production of biological buffers. We can provide a large number of Tris and other types of biological buffer products, and our company can provide product customization and professional after-sales service for customers, and provide professional product sample testing services and packaging customization services for special customers. In any case, Desheng Company must be your best choice for purchasing biological buffers.

People who have not been in contact with luminol may not have a good understanding of what it does. But if you are interested in criminal investigation, you will know that it is the magic of solving crimes. Because it emits a kind of blue light when it encounters blood, even if you wash it with water or detergent, it cannot block its light, but there may be differences in luminous intensity. So what exactly affects the luminous intensity of luminol? The effect of pH on the strength of luminol pH plays a vital role in the luminescence of luminol luminescence system. At lower pH values, the intensity of luminol decreases sharply, while at higher pH values, a significant increase in the intensity of luminol is observed. Their effect on the strength of luminol at different pH. At lower pH values, these compounds showed an inhibitory effect on the intensity of luminol, while at higher pH values, a significant increase in the intensity of luminol was observed. The maximum luminous intensity measured in the range of pH 8.0 and pH 9.5. In this pH range, both suppression and enhancement signals are observed. When we compare the luminous intensity at pH 8.0 and pH 9.5, the relative luminous intensity at pH 8.0 is lower and decreases with a half-life of 20 minutes. However, the relative luminous intensity at pH 9.5 was higher, lasted longer, and then slowly decreased, so 30% luminous intensity was recorded even after 3 hours. Luminol has a strong and stable chemiluminescence signal at alkaline pH. Influence of Luminol Concentration on Luminous Intensity The concentration of luminol is an important factor affecting the luminous intensity. The intensity of luminol's luminescence depends not only on the concentration of luminol, but also on other factors, such as the concentration of oxidants, enzymes, and pH. The effect of luminol concentration was studied by keeping the concentration of H 2 O 2 and silver nanoparticles constant. The concentration of luminol they use is 0.01-1 mmol/L. The maximum luminous intensity recorded at a luminol concentration of 0.3 mmol/L. The luminous intensity increases linearly with the increase of luminol concentration in the range of 0.01 to 0.3 mmol/L. However, a further increase in the concentration of luminol resulted in a decrease in luminous intensity. A number of studies have shown that the luminescence signal increases linearly with the increase of luminol concentration, reaching its maximum intensity at a specific concentration. Above the luminol concentration, the luminescence signal decreases.

Forensic Medicine   Luminol is commonly used in forensic medicine as a diagnostic tool for detecting blood stains. Most crime scene investigations (called criminology) are based on the fact that no traces will not disappear, and small blood particles will stick to most surfaces for many years. Luminol reveals these traces through luminescent chemical reactions between several chemicals and hemoglobin (an oxygen-carrying protein in the blood).   Nucleic acid determination   The luminescent oxygen channel immunoassay (LOCI) type detection method is also suitable for the detection of single nucleotide polymorphism types. Other detection methods based on luminescent nucleic acids include the detection of infectious diseases combined with nucleic acid amplification technology, such as polymerase chain reaction, such as telomere DNA, herpes simplex, Lassa fever virus and Trichomonas vaginalis.   Oncology   HRP molecules catalyze the luminescence reaction between luminol and H2O2 to produce an enhanced luminescence signal. Under optimal conditions, the luminescence intensity depends on the surface coverage of HRP molecules (related to the concentration of p53 protein), and linearly increases with the concentration of p53 protein between 0.01-0.5 nM. The estimated detection limit is 3.8 pM. This assay is a successful method for detecting p53 protein in normal and cancer cell lysates.   DNA Testing   Another successful research application of CL is the detection of gene expression products developed as a substitute for the traditional chloram phenicol acetyltransferase gene. Chemiluminescent dioxetane and luminol derivative substrates can also be used to detect and quantify the gene expression products of placental alkaline phosphatase, β-galactosidase and β-glucuronidase. These measurements are sensitive and have a linear range on several orders of magnitude.   Cell chemiluminescence   The existing cell location methods are not enough. Therefore, the enhanced luminescence of luminol or luminol emitted by polymorphonuclear neutrophils or phagocytes or biological fluids (such as whole blood) is an important tool for cell-based research (including respiratory burst research).   Protein quantification   In routine laboratory research experiments, Western blotting is used to quantify proteins. Western blotting is widely used to study steady-state protein levels, biosynthesis and turnover rates, the effects of mutations on protein stability, and the effects of pharmacological compounds on protein expression.   Environmental monitoring   Luminol can be used to determine the content of metal ions. A method for determining the content of iron ions in seawater has been established and used for marine environmental monitoring.   medicine analysis   The myoglobin-luminol system is used to detect the drug Aniracetam, which is used for the treatment of the central nervous system. The myoglobin conjugate complex of Anracetam catalyzes the CL reaction of luminol, which is enhanced compared with the CL reaction without Anracetam. This method is also used to determine cefazolin sodium in injections and human urine.

Biological buffers are the most commonly used auxiliary reagents in biochemical testing, and buffers are required for almost all liquid phase reaction systems. Its main function is to maintain the pH value of the reaction system. Commonly used buffers include phosphate, acetate, ammonium salt, and Tris base, MOPS, HEPES, etc. in biochemical experiments.   There are many effects of biological buffers on biochemical detection, mainly in the pH value of the solution. The specific effects are illustrated below. A variety of biological buffers   The effect of buffer on enzyme activity:   Most biochemical tests are reactions involving enzymes. The catalytic efficiency of enzymes is greatly affected by pH and temperature. Each enzyme has its optimal pH value (the pH value at which the enzyme catalytic reaction efficiency is maximum) Therefore, biochemical detection involving enzymes needs to first select a buffer with a suitable buffer range according to the optimum pH value of the enzyme preparation used. Such as Trinder’s reagent enzymatic detection, enzyme-linked immunoassay, etc.   The effect of buffer on the structure of macromolecules:   In addition to the effect of the buffer on the catalytic efficiency of the enzyme, it may also affect the structure of the enzyme. If the pH value of the system and the adaptation pH value of the enzyme are too different, the enzyme may be directly inactivated. On the other hand, even if there is no reaction involving enzymes, buffers are necessary. Many macromolecular substances are often involved in biochemical detection, and their structure is also affected by pH.   For example, acridine ester chemiluminescence detection. Although the reaction of acridine ester and hydrogen peroxide does not require enzyme catalysis, it can emit light directly, but in CLIA analysis, acridinium ester is usually labeled protein, antigen, antibody or nucleic acid, these macromolecular substances The structure is complex and is affected by the pH of the system, so biological buffers are also required.   The effect of buffer on osmotic pressure:   Many buffers are organic weak acid and weak base conjugate acid-base pairs. Different buffers have different ionic strengths, which affect the salt concentration and osmotic pressure of the system. HEPES is often used as a buffer for cell culture, and a buffer that affects the osmotic pressure of the cell membrane and may cause rupture cannot be used.   In addition, different buffers have different complexing capabilities for different metal ions. For example, the system containing calcium and magnesium ions uses Tris buffer instead of PBS. The activity of many enzymes and proteins is related to the concentration of metal ions. Desheng is an established manufacturer of biochemical buffers, which can supply more than ten kinds of biological buffers.

Desheng is a professional manufacturer of TRIS (tromethamine) buffer. Our products are sold all over the country and are widely used in the field of biotechnology. Desheng has more than ten years of experience in the production of TRIS. In the future, we will continue to provide TRIS products that meet the needs of customers for the booming global market to ensure excellent functionality and compliance. For traditional TRIS buffer products, product agglomeration is a long-standing headache and huge challenge in the industry. There are many inefficiencies caused by TRIS agglomeration, such as increased labor costs and operating costs to handle agglomeration; another example is to process buffer solutions, which prolongs the time required for mixing, reduces production efficiency, and forms an operating bottleneck . Magnified image of Desheng TRIS crystal Causes of TRIS agglomeration TRIS is a hygroscopic material that will absorb moisture. When the environment and/or storage conditions of TRIS are not ideal, such as being affected by humidity, pressure, temperature and other factors, and lasting for a period of time, it will cause different degrees of agglomeration. The common lumps are loose and large particles in the powder, but they may also form solid lumps. Affected by the transportation time and conditions, the traditional TRIS on the market is often accompanied by agglomeration when it arrives, and in the future storage or daily distribution operations, if the package is re-sealed after the package is opened, there will be a secondary knot. The block phenomenon occurs. Desheng TRIS advantage In order to meet the processing challenges of TRIS buffers on the current market, Desheng Technology produces through proprietary process technology, which is not easy to agglomerate and harden-and does not change the structure of the molecule itself, providing a solution to the problem of agglomeration . Desheng buffer has a larger and rounder particle structure, and it is not easy to agglomerate even under various packaging, transportation and storage conditions. In terms of processing and preparation, key operational benefits can be generated: Desheng TRIS buffer features 1. The adhesion of particles between crystals is low, and the processing of agglomeration is more labor-saving 2. Smoother particle structure makes it easier for the feeding system to disperse and transmit 3. Reduce the number of fine particles, thereby reducing dust emissions 4. No additional additives or anti-coagulants added 5. Less clumping As a professional TRIS (tromethamine) manufacturer, Desheng always insists on providing high-quality products and services. Our fully traceable raw materials, reliable and stable global supply, professional testing and customized packaging solutions provide you with strong support in the biological field-from research and development, application development to production, which is not only our consistent Commitment is our persistence from beginning to end.

Tris base is a weak base with a wide range of uses. It can be used in biological buffers, biopharmaceuticals, coatings, new composite materials, etc. Sodium carbonate is the reference substance for titration calibration of acid concentration, but it has some shortcomings, and Tris can be used as a supplement to sodium carbonate reference substance to replace it for titration calibration of acid concentration. Tris(hydroxymethyl)aminomethane powder Experiment preparation and equipment: Hydrochloric acid: analytically pure; sulfuric acid: analytically pure; sodium carbonate: reference reagent; Tris: reference reagent; methyl red-cresol green ethanol solution. Potentiometric titrator, Lab X workstation, composite pH electrode; muffle furnace; 50mL acid burette and other general laboratory utensils. Use Tris and sodium carbonate to titrate hydrochloric acid or sulfuric acid separately: Manual titration: Weigh the standard reagent Tris (constant weight at 110 degrees Celsius) or anhydrous sodium carbonate (constant weight at 270-300 degrees Celsius) which consumes about 20-30 mL of the sulfuric acid or hydrochloric acid titration solution to be calibrated, weigh to 0.0001g, and dissolve in Add 10 drops of bromocresol green-methyl red indicator to a 250mL Erlenmeyer flask containing 50~100mL of water, and change the acid solution to be calibrated from green to dark red. Boil for 2min. After cooling, continue to titrate until the solution just changes color ( Light gray). Do a blank test for the acid standard titration solution of not more than 0.1mol/L at the same time. Automatic potentiometric titration: Fix the titration cup containing the reference anhydrous sodium carbonate or Tris aqueous solution on the titration stand, connect the PH composite electrode, set the appropriate titration parameters of the automatic potentiometer, and start the titration program to automatically titrate to the end point. (It is appropriate to consume sulfuric acid or hydrochloric acid titrant 2. ~ 30mL). At the same time, make a blank test. Compared with manual titration, automatic potentiometric titration has more advantages. Manual titration adopts calibration indicator. The selection is based on the sudden change in the pH value of the solution near the stoichiometric point of the titrant. The end point is judged by the color change of the indicator, and the color range is affected by different concentrations. The acid content and the quality of the reference material vary. Usually, the indicator method must be used to calibrate the end point color by the potentiometric method. Potentiometric titration is based on potential mutation sites. The potential mutation sites of Tris are more prominent and single, while sodium carbonate has multiple interference mutation sites. Tris potential titration has more advantages in calibrating acid concentration. Desheng has a large-scale Tris production line, and its products are stable and guaranteed.

In the related biochemical testing of enzyme preparations, in addition to measuring the content, concentration, and stability of various indicators to be tested, there are also indicators for detecting enzyme activity, such as blood sugar, blood lipids, and creatinine. For indicators such as transaminase and sarcosine oxidase, enzyme activity needs to be measured.   Generally speaking, enzyme activity is the activity of enzyme catalysis, which involves a kinetic parameter of the enzyme-the Michaelis constant Km, which means the concentration of the substrate (S) when the enzymatic reaction reaches half of the maximum speed (Vm) . The speed of the enzyme reaction is not uniform, not linear like the concentration, but the number of meters in Changshu is constant, which is a characteristic physical quantity of the enzyme. The Michaelis constant of the enzyme changes with the measured substrate type, reaction temperature, pH and ionic strength. Under the same conditions, no matter what the concentration of the enzyme is, the concentration of the required substrate is the same when the maximum reaction rate is reached.   Measurement method of Michaelis constant of sarcosine oxidase: Prepare a sarcosine solution with a concentration of 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0mmo1/L with Tris-HC1 buffer of pH 8.0, and react at 37°C for 5 minutes Determine the initial oxidation activity of SOX at different sarcosine concentrations. The reaction rate V and 1/V are obtained. According to the Lineweaver-Burk double reciprocal mapping method, with 1/[s] as the abscissa and 1/V as the ordinate, the Km and Vmax of SOX to sarcosine were calculated.   Conclusion of Michaelis constant of sarcosine oxidase: The Michaelis constant can be used to judge the specificity of the enzyme. The smaller the Km value, the greater the affinity between the enzyme and the substrate, and the more suitable the substrate is as the natural substrate of the enzyme. According to the test and calculation of sarcosine oxidase above, the Michaelis equation is y=1232.5X+8.7012 and the correlation coefficient is 0.9947: the calculated Km and Vmax values ​​of SOX to sarcosine are 141.6mmol/L and 0.115mmol, respectively /(L.min).   It should be noted that sarcosine oxidase SOX from different sources has a certain difference in the Michaelis constant of sarcosine. For example, the Km value of SOX from Corynebaclerium to sarcosine is 21mmol/L. Since the Michaelis constant has nothing to do with the concentration of the enzyme and the type of enzyme, this point can also be used for enzyme identification or determination. Desheng Biochemical focuses on the field of biochemical detection, and provides a variety of enzyme preparations including SOX, cholesterol esterase, glucose oxidase, etc.