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The following is the specific HPLC information:
High efficiency and automation have become the development trend of experimental testing instruments, and second-hand high performance liquid chromatography can meet such needs and expectations. Do you have a systematic understanding of HPLC? Some people may not know. Therefore, now Jingke Ruida Second-hand Instrument has compiled a summary article about second-hand HPLC for you, hoping to help you.
High performance liquid chromatograph is mainly composed of five parts: chromatographic pump and controller, sampler, chromatographic column, detector and data processing and control. The principle of separation is a physical process. The mobile phase carries the compounds to be analyzed and other stored substances through the chromatographic column. Different substances have different retention times on the stationary phase, thus achieving separation. Retention time is used for qualitative analysis, and peak height or peak area is quantified. After the separated components pass through the ultraviolet detector in turn.
Characteristics of second-hand HPLC instruments: "three heights, one width and one speed"
1, high pressure: the mobile phase is liquid, and it is subject to great resistance when flowing through the chromatographic column. In order to pass through the chromatographic column quickly, high pressure should be applied to the carrier liquid.
2. High efficiency: high separation efficiency. Stationary phase and mobile phase can be selected to achieve good separation effect of purple, which is many times higher than that of industrial distillation column and gas chromatography.
3. High sensitivity: the ultraviolet detector can reach 0.0 1ng, and the sample volume is in the order of μ L. ..
4. Wide application range: HPLC can analyze more than 70% of organic compounds, especially those with high boiling point, macromolecules, strong polarity and poor thermal stability, showing advantages.
5. The analysis speed is fast, and the flow rate of carrier liquid is fast: much faster than that of classical liquid chromatography. It usually takes 15 ~ 30 min to analyze a sample, and some samples can even be completed within 5min, which is generally less than1h. In addition, HPLC has the advantages of reusable chromatographic column, no damage to the sample and easy recovery.
Separation principle of high performance liquid chromatography
According to different separation principles, high performance liquid chromatography can be divided into the following main types: liquid-liquid partition chromatography (LLC), chemical bonding chromatography, liquid-solid adsorption chromatography, ion exchange chromatography, steric exclusion chromatography and so on.
1, liquid-liquid partition chromatography (LLC) is a process of separating components based on the relative solubility difference between stationary phase and mobile phase.
2. Chemical bonding phase chromatography is to bond the organic groups of stationary liquid to the surface of carrier through chemical reaction, so as to overcome the loss of stationary liquid and achieve the purpose of separation.
3. Liquid-solid adsorption chromatography is a process of separating each other according to the different adsorption of each component in the sample.
4. Ion exchange chromatography is a method that combines ion exchange principle with liquid chromatography technology to determine cations and anions in solution.
5. Spatial exclusion chromatography is a process of separating molecules with different volumes by using chemically inert porous substances as stationary phase, which makes the sample components affected by the pore size of the stationary phase.
Application field of second-hand high performance liquid chromatograph
High performance liquid chromatography only requires that the sample can be made into solution, which is not limited by the volatility of the sample. The mobile phase can be selected in a wide range, and there are many kinds of stationary phases, which can separate thermally unstable and nonvolatile, dissociated and inseparable substances with various molecular weight ranges.
Combined with sample pretreatment technology, high resolution and high sensitivity achieved by HPLC make it possible to separate and simultaneously determine substances with very similar properties, and trace components in complex phases can be separated. With the development of stationary phase, it is possible to complete the separation of biochemical substances under the condition of fully maintaining their activity.
High performance liquid chromatography has become a promising method to solve biochemical analysis problems. High performance liquid chromatography (HPLC) has the advantages of high resolution, high sensitivity, high speed, reusable chromatographic column and easy collection of effluent components, and is widely used in biochemistry, food analysis, medical research, environmental analysis, inorganic analysis and other fields. The combination of high performance liquid chromatography and structural instruments is an important development direction.
Application of second-hand high performance liquid chromatography in food analysis
In food production and processing, preservatives, pigments, sweeteners, preservatives and other chemicals are often added. Too high a content of them will also cause human health problems. In addition, due to the deterioration of our environment, food will be polluted by harmful trace elements, which will endanger our health. Therefore, high performance liquid chromatography plays an important role in food analysis.
Analysis of condiments in food
High performance liquid chromatography can also be used for the separation and analysis of food condiments. For example, J.D.BARANOWSKI reported the method of separating spicy components from ginger by high performance liquid chromatography. Another example is Bbathnanathic M and BuckleH. A method for the determination of piperine in pepper by HPLC is reported.
2. Separation of organic acids in food
Organic acids in food are the main source of sour taste in food, and the content and composition of organic acids in food have great influence on the taste of food. Therefore, the qualitative and quantitative analysis of organic acids in food is not only of great significance to food nutrition research, but also of great importance to the quality management of food production process. When determining organic acids by HPLC, the homogenate of food samples should be extracted and centrifuged first, and then the sample solution should be filtered by 0.3um filter membrane. Using (NH4) 2HPO4-H3PO4 buffer (pH=2.7) as the mobile phase, it was separated on C 18 chromatographic column by high performance liquid chromatography, and detected by ultraviolet detector. The wavelength was 2 10nm, expressed by peak height or peak area.
3. Analysis of additives in food
There are not only many kinds of food additives, but also different functions, and there is no unified standard for classification. Therefore, the determination of additives is more demanding. The determination of food additives, like other analysis, should be separated from the complex mixture first, and then the appropriate analysis method should be selected according to the different physical and chemical properties of the detected substances. The application of HPLC in food additives can not only improve the quality and nutritional value of food, but also improve the sensory characteristics brought by food. Food additives can prevent food from spoilage, extend the shelf life and provide us with delicious food. We can determine the content of saccharin sodium in sweetener by HPLC. Prepare saccharin sodium standard stock solution and standard use solution, stir the sample with slight heat, add ammonia water (1+ 1) to adjust the pH to 7 ~ 7, prepare chromatographic column with methanol-ammonium acetate solution (0.02mol/L)(5+95) as mobile phase, and take sample treatment solution and standard use solution1respectively.
4. Separation and analysis of sugar in food.
Starch is a kind of polysaccharide, which widely exists in roots, stems, leaves, seeds and other tissues of plants. It is an important part of human food and the main source of human heat. Starch is a polymer composed of glucose units, and its hydrolysate is monosaccharide. We can analyze the hydrolysate of wheat starch by HPLC.
5. Separation and analysis of vitamins in food.
Vitamin is a trace organic substance that people and animals need to get from food in order to maintain normal physiological functions, and it plays an important role in human growth, metabolism and development. In the determination of fat-soluble vitamins, it is usually necessary to treat samples by saponification, remove lipids with water, extract fat-soluble vitamins with organic solvents, and then dissolve them in appropriate solvents for determination.
6. Application in other food analysis
HLPC is not only used in the above fields, but also widely used in the detection of drug residues in food, the detection of prohibited components in food and the separation and analysis of nutritional components in food. Peng Jinfeng established a HPLC method for the determination of formaldehyde in edible fungi. Dorri et al. established a method for the determination of soybean isoflavones in health food by high performance liquid chromatography. The research and experiments of these methods expand the application of high performance liquid chromatography in food, and provide a foundation for the wide application of high performance liquid chromatography in food separation and analysis in the future.
Above, all the contents about the second-hand HPLC instrument and the knowledge summary of the second-hand HPLC instrument compiled for the second-hand instruments of Jingke Kerui are only extracted because of the complicated information. I hope everyone can have a preliminary understanding of HPLC! If you have any other questions, please leave us a message and we will serve you wholeheartedly!
Quoted from the Beijing University of Science and Technology Rui official website Sub-page.