Distribution Chromatography
Distributive chromatography is a chromatographic technique that utilizes different partition coefficients of the components in the mixture to achieve separation purposes, and is equivalent to a continuous solvent extraction method.
In partition chromatography, the stationary phase is a polar solvent (eg, water, dilute sulfuric acid, methanol, etc.). Such a solvent can be tightly combined with a porous support (usually a small adsorbent, a weakly reactive inert substance such as starch, cellulose powder, filter paper, etc.) to be in a non-flowing state; the mobile phase is a non-polar organic Solvent. The partition coefficient (a) refers to the concentration ratio of the substance at equilibrium between the stationary phase and the mobile phase under certain temperature and pressure conditions. Shanghai Chuangsai Technology provides 9005-84-9, soluble starch, Starch soluble, pharmaceutical grade, commodity number: C16-S10416-500g, price 40 yuan.
During the chromatography process, when the organic solvent mobile phase flows through the sample point, the solute in the sample is partially transferred to the mobile phase to move forward according to its partition coefficient. When passing through the front stationary phase, the solute in the mobile phase is distributed and a portion enters the stationary phase. Through such continuous flow and redistribution, the solute continues to advance along the flow direction. Various solutes move at different speeds due to different partition coefficients. For substances with a large distribution coefficient, the distribution is more in the stationary phase, the distribution in the mobile phase is less, and the solute moves slower. The substance with a smaller distribution coefficient moves faster. Thereby separating substances with different distribution coefficients.
The support plays a role in supporting the stationary phase in the distribution chromatography, and is also divided into two types, column chromatography and thin layer chromatography, depending on the mode of use. Paper chromatography using filter paper as a support is the most commonly used partition chromatography. In the experiment, filter paper with appropriate thickness and uniform texture and containing as little metal ions (calcium, copper, magnesium, iron, etc.) should be used as the support. The water adsorbed in the filter paper (about 20-22%) is a commonly used stationary phase. Phenols and alcohols are commonly used mobile phases. The layering method can be mostly vertical (Fig. 3-1) or horizontal. A sample point to be separated is applied to one end of the paper to move the mobile phase therethrough, so that a distribution phenomenon occurs between the two phases. Depending on the partition coefficient in each group in the sample, they gradually concentrate on different parts of the paper. The moving speed of each component on the filter paper can be expressed by the mobility (Rf). Shanghai Chuangsai Technology provides anhydrous copper acetate, Cupric Acetate Anhydrous, 99.999% metals basis, 142-71-2, commodity number: C16-C10692-25g, price 1487 yuan.
In paper chromatography, the magnitude of the Rf value depends primarily on the partition coefficient of the component. If the distribution coefficient is large, the moving speed is slow, and the Rf value is also small; otherwise, the smaller the distribution coefficient is, the moving speed is faster and the Rf value is also larger. Because each substance has a certain partition coefficient for a certain solvent system under certain conditions, the Rf value is also constant. Therefore, the separated substance can be identified based on the Rf value.
Sometimes the Rf values ​​of several components in a solvent system are similar and are not easy to separate. At this time, after the first chromatography, the filter paper can be blown dry and reversed by 90o, and then another solvent system can be used for the second chromatography, and a satisfactory separation effect can often be obtained. This method is called "two-way paper chromatography" (Figure 3-2).
Shanghai Chuangsai Technology has excellent performance, interleukin cytokines, fetal bovine serum, electrophoresis equipment scientific instruments, raw material drug standards, chemical reagents, cell culture consumables, Shanghai Chuangsai, mass products special promotions, welcome to inquire!
Outdoor Beach Chair brings you a wonderful lounge time at seaside or poolside.The materials synthetic PE rattan,aluminium frame and waterproof cushion are resistant to difference weather conditions and easy to maintain.
Outdoor Beach Chair is crafted from rattan wicker weaved into an aluminium frame. This combination help make this chair durable and comfortable all at once. The adjustable backrest allows you to adjust to different positions so that you can relax on the patio or by the pool.
Features
· For outdoor and indoor use
· High quality rattan plait
· Suitable to all weather conditions
· Easy to maintain
· Matches any outdoor decor
· Quick to assemble
· Adjustable backrest
Maintenance tips
· Do not use any abrasive cleaning agents for cleaning
· Clean the chaise lounge with a damp, soft cloth (you may use a mild cleaning agent) and wipe it dry afterwards
· In case of ceaseless heavy rain or during the winter, the furniture should be stored inside or have a protective cover on it
Outdoor Beach Chair is ranged in different style: Rattan Chair,Sing Mesh Chair,Aluminium Powder Coat Chair.Single and double chairs are available for option.
If you have any questions, please contact with us directly. Outdoor Sofa Furniture are produced
by Golden Eagle Outdoor Furniture With High Quality and Good Appearance. Welcome you can visit our Factory.For any inquiry,Please send mail directly to us.
Rattan Beach Chair,Sun Lounger Beach Chair,Pool Beach Chair,Chaise Lounger Beach Chair
Golden Eagle Outdoor Furniture Co., LTD. , https://www.geleisurefurniture.com