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Chiral Thin-layer Chromatography
Chiral thin-layer chromatography is a variant of liquid chromatography that is employed for the separation of enantiomers. It is necessary to use either * a chiral stationary phase or * a chiral additive in the mobile phase. The chiral stationary phase can be prepared by mixing chirally pure reagents such as L-amino acid, or brucine, or a chiral ligand exchange reagent with silica gel slurry, or by impregnation of the TLC plate in the solution of a chiral reagent. The principle can also be applied to chemically modify the stationary phase before making the plate via bonding of the chiral moieties of interest to the reactive groups of the layer material. See also * Chiral column chromatography Chiral column chromatography is a variant of column chromatography that is employed for the separation of chiral compounds, i.e. enantiomers, in mixtures such as racemates or related compounds. The chiral stationary phase (CSP) is made of a support ... References Chromatography ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photo Of A TLC Plate Baclofen
A photograph (also known as a photo, or more generically referred to as an ''image'' or ''picture'') is an image created by light falling on a photosensitive surface, usually photographic film or an electronic image sensor. The process and practice of creating such images is called photography. Most photographs are now created using a smartphone or camera, which uses a lens to focus the scene's visible wavelengths of light into a reproduction of what the human eye would perceive. Etymology The word ''photograph'' was coined in 1839 by Sir John Herschel and is based on the Greek φῶς (''phos''), meaning "light", and γραφή (''graphê''), meaning "drawing, writing", together meaning "drawing with light". History The first permanent photograph, a contact-exposed copy of an engraving, was made in 1822 using the bitumen-based "heliography" process developed by Nicéphore Niépce. The first photographs of a real-world scene, made using a camera obscura, followed a few years ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liquid 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enantiomer
In chemistry, an enantiomer (Help:IPA/English, /ɪˈnænti.əmər, ɛ-, -oʊ-/ Help:Pronunciation respelling key, ''ih-NAN-tee-ə-mər''), also known as an optical isomer, antipode, or optical antipode, is one of a pair of molecular entities which are mirror images of each other and non-superposable. Enantiomer molecules are like right and left hands: one cannot be superposed onto the other without first being converted to its mirror image. It is solely a relationship of chirality (chemistry), chirality and the permanent three-dimensional relationships among molecules or other chemical structures: no amount of re-orientation of a molecule as a whole or conformational isomerism, conformational change converts one chemical into its enantiomer. Chemical structures with chirality rotate plane-polarized light. A mixture of equal amounts of each enantiomer, a ''racemic mixture'' or a ''racemate'', does not rotate light. Stereoisomers include both enantiomers and diastereomers. Diaste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chiral Stationary Phase
Chiral column chromatography is a variant of column chromatography that is employed for the separation of chiral compounds, i.e. enantiomers, in mixtures such as racemates or related compounds. The chiral Stationary phase (chemistry), stationary phase (CSP) is made of a support, usually silica based, on which a chiral reagent or a macromolecule with numerous chiral centers is bonded or immobilized. The chiral stationary phase can be prepared by attaching a chiral compound to the surface of an achiral support such as silica gel. For example, one class of the most commonly used chiral stationary phases both in liquid chromatography and supercritical fluid chromatography is based on oligosaccharides such as Amylose Cellulose or Cyclodextrin (in particular with β-cyclodextrin, a seven sugar ring molecule) immobilized on silica gel. The principle can be also applied to the fabrication of Monolithic HPLC columns or gas chromatography, Gas Chromatography columns. or Supercritical fluid ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
L-amino Acid
Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although over 500 amino acids exist in nature, by far the most important are the 22 α-amino acids incorporated into proteins. Only these 22 appear in the genetic code of life. Amino acids can be classified according to the locations of the core structural functional groups ( alpha- , beta- , gamma- amino acids, etc.); other categories relate to polarity, ionization, and side-chain group type (aliphatic, acyclic, aromatic, polar, etc.). In the form of proteins, amino-acid '' residues'' form the second-largest component (water being the largest) of human muscles and other tissues. Beyond their role as residues in proteins, amino acids participate in a number of processes such as neurotransmitter transport and biosynthesis. It is thought that they played a key role in enabling life on Earth and its emergence. Amino acids are formally named by the IUPAC- IUBMB Joint Commissio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brucine
Brucine is an alkaloid closely related to strychnine, most commonly found in the ''Strychnos nux-vomica'' tree. Brucine poisoning is rare, since it is usually ingested with strychnine, and strychnine is more toxic than brucine. In chemical synthesis, it can be used as a tool for stereospecific chemical syntheses. Brucine's name derives from this of the genus '' Brucea'', named after James Bruce who brought back ''Brucea antidysenterica'' from Ethiopia. History Brucine was discovered in 1819 by the French chemist Pelletier and the French pharmacist Caventou in the bark of the ''Strychnos nux-vomica'' tree. While its chemical structure was not deduced until much later, it was determined that it was closely related to strychnine in 1884 when the chemist Hanssen converted both strychnine and brucine into the same molecule. Identification Brucine can be detected and quantified using liquid chromatography-mass spectrometry. Historically, brucine was distinguished from strych ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angewandte Chemie International Edition In English
''Angewandte Chemie'' (, meaning "Applied Chemistry") is a weekly peer-reviewed scientific journal that is published by Wiley-VCH on behalf of the German Chemical Society (Gesellschaft Deutscher Chemiker). Publishing formats include feature-length reviews, short highlights, research communications, minireviews, essays, book reviews, meeting reviews, correspondences, corrections, and obituaries. This journal contains review articles covering all aspects of chemistry. According to the ''Journal Citation Reports'', the journal had a 2023 impact factor of 16.1. Editions The journal appears in two editions with separate volume and page numbering: a German edition, ''Angewandte Chemie'', and a fully English-language edition, ''Angewandte Chemie International Edition''. The editions are identical in content with the exception of occasional reviews of German-language books or German translations of IUPAC recommendations. Publication history In 1887, Ferdinand Fischer established the ''Zei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chiral Column Chromatography
Chiral column chromatography is a variant of column chromatography that is employed for the separation of chiral compounds, i.e. enantiomers, in mixtures such as racemates or related compounds. The chiral stationary phase (CSP) is made of a support, usually silica based, on which a chiral reagent or a macromolecule with numerous chiral centers is bonded or immobilized. The chiral stationary phase can be prepared by attaching a chiral compound to the surface of an achiral support such as silica gel. For example, one class of the most commonly used chiral stationary phases both in liquid chromatography and supercritical fluid chromatography is based on oligosaccharides such as Amylose Cellulose or Cyclodextrin (in particular with β-cyclodextrin, a seven sugar ring molecule) immobilized on silica gel. The principle can be also applied to the fabrication of Monolithic HPLC columns or Gas Chromatography columns. or Supercritical Fluid Chromatography columns. Principle of Chiral Colu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromatography
In chemical analysis, chromatography is a laboratory technique for the Separation process, 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' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
