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Size-exclusion Chromatography
Size-exclusion chromatography (SEC), also known as molecular sieve chromatography, is a chromatographic method in which molecules in solution are separated by their size, and in some cases molecular weight. It is usually applied to large molecules or macromolecular complexes such as proteins and industrial polymers. Typically, when an aqueous solution is used to transport the sample through the column, the technique is known as gel-filtration chromatography, versus the name gel permeation chromatography, which is used when an organic solvent is used as a mobile phase. The chromatography column is packed with fine, porous beads which are commonly composed of dextran, agarose, or polyacrylamide polymers. The pore sizes of these beads are used to estimate the dimensions of macromolecules. SEC is a widely used polymer characterization method because of its ability to provide good molar mass distribution (Mw) results for polymers. Applications The main application of gel-filtration chr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromatography
In chemical analysis, chromatography is a laboratory technique for the separation of a mixture into its components. The mixture is dissolved in a fluid solvent (gas or liquid) called the ''mobile phase'', which carries it through a system (a column, a capillary tube, a plate, or a sheet) on which a material called the ''stationary phase'' is fixed. Because the different constituents of the mixture tend to have different affinities for the stationary phase and are retained for different lengths of time depending on their interactions with its surface sites, the constituents travel at different apparent velocities in the mobile fluid, causing them to separate. The separation is based on the differential partitioning between the mobile and the stationary phases. Subtle differences in a compound's partition coefficient result in differential retention on the stationary phase and thus affect the separation. Chromatography may be preparative or analytical. The purpose of preparativ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyacrylamide
Polyacrylamide (abbreviated as PAM) is a polymer with the formula (-CH2CHCONH2-). It has a linear-chain structure. PAM is highly water-absorbent, forming a soft gel when hydrated. In 2008, an estimated 750,000,000 kg were produced, mainly for water treatment and the paper and mineral industries. Physicochemical properties Polyacrylamide is a polyolefin. It can be viewed as polyethylene with amide substituents on alternating carbons. Unlike various nylons, polyacrylamide is not a polyamide because the amide groups are not in the polymer backbone. Owing to the presence of the amide (CONH2) groups, alternating carbon atoms in the backbone are stereogenic (colloquially: chiral). For this reason, polyacrylamide exists in atactic, syndiotactic, and isotactic forms, although this aspect is rarely discussed. The polymerization is initiated with radicals and is assumed to be stereorandom. Copolymers and modified polymers Linear polyacrylamide is a water-soluble polymer. Other p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Size Exclusion Chromatography Apparatus
Size in general is the magnitude or dimensions of a thing. More specifically, ''geometrical size'' (or ''spatial size'') can refer to linear dimensions (length, width, height, diameter, perimeter), area, or volume. Size can also be measured in terms of mass, especially when assuming a density range. In mathematical terms, "size is a concept abstracted from the process of measuring by comparing a longer to a shorter". Size is determined by the process of comparing or measuring objects, which results in the determination of the magnitude of a quantity, such as length or mass, relative to a unit of measurement. Such a magnitude is usually expressed as a numerical value of units on a previously established spatial scale, such as meters or inches. The sizes with which humans tend to be most familiar are body dimensions (measures of anthropometry), which include measures such as human height and human body weight. These measures can, in the aggregate, allow the generation of c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of Polymer Science Part A
''Journal of Polymer Science'' is a peer-reviewed journal of polymer science currently published in multiple parts by John Wiley & Sons. It was originally established as the ''Journal of Polymer Science'' in 1946 by Interscience Publishers and the founding editor Herman F. Mark, but it was split in various parts in 1962. The journal has undergone re-organization several times since. In 2020, the journal will consolidate in one single publication. The editor-in-chief is Ying Jia. History ;Establishment *''Journal of Polymer Science'' (1946–1962), ;First re-organization *''Journal of Polymer Science Part A: General Papers'' (1963–1965), **''Journal of Polymer Science Part A-1: Polymer Chemistry'' (1966–September 1972), **''Journal of Polymer Science Part A-2: Polymer Physics'' (1966–September 1972), *''Journal of Polymer Science Part B: Polymer Letters'' (1963–September 1972), *''Journal of Polymer Science Part C: Polymer Symposia'' (1963–1972), The coverage of bi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polystyrene
Polystyrene (PS) is a synthetic polymer made from monomers of the aromatic hydrocarbon styrene. Polystyrene can be solid or foamed. General-purpose polystyrene is clear, hard, and brittle. It is an inexpensive resin per unit weight. It is a poor barrier to oxygen and water vapour and has a relatively low melting point. Polystyrene is one of the most widely used plastics, the scale of its production being several million tonnes per year. Polystyrene can be naturally transparent, but can be colored with colorants. Uses include protective packaging (such as packing peanuts and in the jewel cases used for storage of optical discs such as CDs and occasionally DVDs), containers, lids, bottles, trays, tumblers, disposable cutlery, in the making of models, and as an alternative material for phonograph records. As a thermoplastic polymer, polystyrene is in a solid (glassy) state at room temperature but flows if heated above about 100 °C, its glass transition temperature. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dow Chemical Company
The Dow Chemical Company, officially Dow Inc., is an American multinational chemical corporation headquartered in Midland, Michigan, United States. The company is among the three largest chemical producers in the world. Dow manufactures plastics, chemicals, and agricultural products. With a presence in about 160 countries, it employs about 54,000 people worldwide. Dow has been called the "chemical companies' chemical company," as its sales are to other industries rather than directly to end-use consumers. Dow is a member of the American Chemistry Council. In 2015, Dow and fellow chemical company DuPont agreed to a corporate reorganization which involved the merger and split of Dow and DuPont into three different companies. The plan commenced in 2017, when Dow and DuPont merged to form DowDuPont, and finalized in April 2019, as the materials science division was spunoff from DowDuPont and took the name of the Dow Chemical Company. History Early history Dow was founded in 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nature Methods
''Nature Methods'' is a monthly peer-reviewed scientific journal covering new scientific techniques. It was established in 2004 and is published by Springer Nature under the Nature Portfolio. Like other ''Nature'' journals, there is no external editorial board and editorial decisions are made by an in-house team, although peer review by external experts forms a part of the review process. Every year, the journal highlights a field, approach, or technique that has enabled recent major advances in life sciences research as the "Method of the Year". According to the ''Journal Citation Reports'', the journal had a 2021 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a scientometric index calculated by Clarivate that reflects the yearly mean number of citations of articles published in the last two years in a given journal, as i ... of 47.99, ranking it first in the category "Biochemical Research Methods". References External link ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Per Flodin
Per is a Latin preposition which means "through" or "for each", as in per capita. Per or PER may also refer to: Places * IOC country code for Peru * Pér, a village in Hungary * Chapman code for Perthshire, historic county in Scotland Math and statistics * Rate (mathematics), ratio between quantities in different units, described with the word "per" * Price–earnings ratio, in finance, a measure of growth in earnings * Player efficiency rating, a measure of basketball player performance * Partial equivalence relation, class of relations that are symmetric and transitive * Physics education research Science * Perseus (constellation), standard astronomical abbreviation * Period (gene) or ''per'' that regulates the biological clock and its corresponding protein PER * Protein efficiency ratio, of food * PER or peregrinibacteria, a candidate bacterial phylum Media and entertainment * PeR (band), a Latvian pop band * ''Per'' (film), a 1975 Danish film Transport * IATA cod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jerker Porath
Jerker Porath, (23 October 1921 – 21 January 2016) was a Swedish biochemist who invented several separation methods for biomolecules. He was born in Sala.Editorial - 80th Birthday of Professor Jerker Porath in ''Chromatographia'' (2001), vol. 54, p. 431-432 Porath studied at and initially did research in under , where he got his [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Environmental Science & Technology
''Environmental Science & Technology'' is a biweekly peer-reviewed scientific journal published since 1967 by the American Chemical Society. It covers research in environmental science and environmental technology, including environmental policy. ''Environmental Science & Technology'' has a sister journal, ''Environmental Science & Technology Letters'', which publishes short communications. The editor-in-chief of ''Environmental Science & Technology'' is Prof. Julie Zimmerman (Yale University). Previous editors have been: David Sedlak (University of California, Berkeley, 2014 - 2020), James J. Morgan (California Institute of Technology; founding editor, 1967-1975), Russell F. Christman (University of North Carolina, 1975-1987), William H. Glaze (University of North Carolina, 1987-2003) and Jerald L. Schnoor (University of Iowa, 2002-2014). Abstracting and indexing According to the ''Journal Citation Reports'', the journal has a 2021 impact factor of 11.357. The journal is abstra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gel Electrophoresis
Gel electrophoresis is a method for separation and analysis of biomacromolecules ( DNA, RNA, proteins, etc.) and their fragments, based on their size and charge. It is used in clinical chemistry to separate proteins by charge or size (IEF agarose, essentially size independent) and in biochemistry and molecular biology to separate a mixed population of DNA and RNA fragments by length, to estimate the size of DNA and RNA fragments or to separate proteins by charge. Nucleic acid molecules are separated by applying an electric field to move the negatively charged molecules through a matrix of agarose or other substances. Shorter molecules move faster and migrate farther than longer ones because shorter molecules migrate more easily through the pores of the gel. This phenomenon is called sieving. Proteins are separated by the charge in agarose because the pores of the gel are too small to sieve proteins. Gel electrophoresis can also be used for the separation of nanoparticles. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fractionation
Fractionation is a separation process in which a certain quantity of a mixture (of gases, solids, liquids, enzymes, or isotopes, or a suspension) is divided during a phase transition, into a number of smaller quantities (fractions) in which the composition varies according to a gradient. Fractions are collected based on differences in a specific property of the individual components. A common trait in fractionations is the need to find an optimum between the amount of fractions collected and the desired purity in each fraction. Fractionation makes it possible to isolate more than two components in a mixture in a single run. This property sets it apart from other separation techniques. Fractionation is widely employed in many branches of science and technology. Mixtures of liquids and gases are separated by fractional distillation by difference in boiling point. Fractionation of components also takes place in column chromatography by a difference in affinity between stationary p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
