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In analytical chemistry, potentiometric titration is a technique similar to direct titration of a redox reaction. It is a useful means of characterizing an acid. No indicator is used; instead the electric potential is measured across the analyte, typically an electrolyte solution. To do this, two electrodes are used, a... | 0 | Chromatography + Titration + pH indicators |
A screw displacement (also screw operation or rotary translation) is the composition of a rotation by an angle φ about an axis (called the screw axis) with a translation by a distance d along this axis. A positive rotation direction usually means one that corresponds to the translation direction by the right-hand rule.... | 1 | Crystallography |
"Litigation science" describes analysis or data developed or produced expressly for use in a trial versus those produced in the course of independent research. This distinction was made by the U.S. 9th Circuit Court of Appeals when evaluating the admissibility of experts.
This uses demonstrative evidence, which is evid... | 0 | Chromatography + Titration + pH indicators |
Many alloys of elements that resemble each other chemically will form a structure at higher temperatures where the two elements occupy similar positions in the lattice at random. At lower temperatures ordering may occur where crystallographic positions are no longer equivalent because one element preferentially occupie... | 1 | Crystallography |
Liquid chromatography-mass spectrometry (LC/MS) couples high resolution chromatographic separation with MS detection. As the system adopts the high separation of HPLC, analytes which are in the liquid mobile phase are often ionized by various soft ionization methods including atmospheric pressure chemical ionization (... | 0 | Chromatography + Titration + pH indicators |
In a common FPLC strategy, a resin is chosen that the protein of interest will bind to by a charge interaction while in buffer A (the running buffer) but become dissociated and return to solution in buffer B (the elution buffer). A mixture containing one or more proteins of interest is dissolved in 100% buffer A and pu... | 0 | Chromatography + Titration + pH indicators |
Although the most common perovskite compounds contain oxygen, there are a few perovskite compounds that form without oxygen. Fluoride perovskites such as NaMgF are well known. A large family of metallic perovskite compounds can be represented by RTM (R: rare-earth or other relatively large ion, T: transition metal ion ... | 1 | Crystallography |
The Laves graph has been suggested as an allotrope of carbon, analogous to the more common graphene and graphite carbon structure which also have three bonds per atom at 120° angles. In graphene, adjacent atoms have the same bonding planes as each other, whereas in the Laves graph structure the bonding planes of adjace... | 1 | Crystallography |
Twinning is a form of symmetrical intergrowth between two or more adjacent crystals of the same mineral. It differs from the ordinary random intergrowth of mineral grains in a mineral deposit, because the relative orientations of the two crystal segments show a fixed relationship that is characteristic of the mineral s... | 1 | Crystallography |
When used as an indicator in an EDTA titration, the characteristic blue end-point is reached when sufficient EDTA is added and the metal ions bound to the indicator are chelated by EDTA, leaving the free indicator molecule.
Eriochrome Black T has also been used to detect the presence of rare earth metals. | 0 | Chromatography + Titration + pH indicators |
In crystal growth, a Knudsen cell is an effusion evaporator source for relatively low partial pressure elementary sources (e.g. Ga, Al, Hg, As). Because it is easy to control the temperature of the evaporating material in Knudsen cells, they are commonly used in molecular-beam epitaxy. | 1 | Crystallography |
A column is prepared by packing a solid adsorbent into a cylindrical glass or plastic tube. The size will depend on the amount of compound being isolated. The base of the tube contains a filter, either a cotton or glass wool plug, or glass frit to hold the solid phase in place. A solvent reservoir may be attached at th... | 0 | Chromatography + Titration + pH indicators |
In crystallography, interstitial sites, holes or voids are the empty space that exists between the packing of atoms (spheres) in the crystal structure.
The holes are easy to see if you try to pack circles together; no matter how close you get them or how you arrange them, you will have empty space in between. The same... | 1 | Crystallography |
Plane-wave topography can be made to extract an additional wealth of information from a sample by recording not just one image, but an entire sequence of topographs all along the sample's rocking curve. By following the diffracted intensity in one pixel across the entire sequence of images, local rocking curves from ve... | 1 | Crystallography |
Amperometric titration refers to a class of titrations in which the equivalence point is determined through measurement of the electric current produced by the titration reaction. It is a form of quantitative analysis. | 0 | Chromatography + Titration + pH indicators |
The basic driving force for protein crystallization is to optimize the number of bonds one can form with another protein through intermolecular interactions. These interactions depend on electron densities of molecules and the protein side chains that change as a function of pH. The tertiary and quaternary structure of... | 1 | Crystallography |
Argentation chromatography is chromatography using a stationary phase that contains silver salts. Silver-containing stationary phases are well suited for separating organic compounds on the basis of the number and type of alkene groups. The technique is employed for gas chromatography and various types of liquid chroma... | 0 | Chromatography + Titration + pH indicators |
Coupled substitution is the geological process by which two elements simultaneous substitute into a crystal in order to maintain overall electrical neutrality and keep the charge constant. In forming a solid solution series, ionic size is more important than ionic charge, as this can be compensated for elsewhere in the... | 1 | Crystallography |
In Cartesian coordinates the 3 basis vectors are represented by a cell tensor :
The volume of the unit cell, , is given by the determinant of the cell tensor:
For the special case of a cubic, tetragonal, or orthorhombic cell, the matrix is diagonal, and we have that: | 1 | Crystallography |
Cibacron Blue F3GA, Procion Blue HB, or Reactive blue 2 is a purinergic receptor antagonist, such as P2Y purinoceptor, and also an ATP receptor channels antagonist. It has a formula of CHClNOS and a molecular weight of 774.2 g/mol. Cibacron blue is soluble in water and DMSO, however insoluble in ethanol. In water, satu... | 0 | Chromatography + Titration + pH indicators |
In crystallography, a Wyckoff position is any point in a set of points whose site symmetry groups (see below) are all conjugate subgroups one of another. Crystallography tables give the Wyckoff positions for different space groups. | 1 | Crystallography |
There are two types of twinning that can occur during growth, accidental and ones where the twinned structure has lower energy.
In accidental growth twinning an atom joins a crystal face in a less than ideal position, forming a seed for growth of a twin. The original crystal and its twin then grow together and closely ... | 1 | Crystallography |
Meyer sets include
*The points of any lattice
*The vertices of any rhombic Penrose tiling
*The Minkowski sum of another Meyer set with any nonempty finite set
*Any relatively dense subset of another Meyer set | 1 | Crystallography |
Tashiro's indicator is a pH indicator (pH value: 4.4–6.2), mixed indicator composed of a solution of methylene blue (0.1%) and methyl red (0.03%) in ethanol or in methanol.
It can be used e.g. for the titration of ammonia in Kjeldahl analysis. | 0 | Chromatography + Titration + pH indicators |
HPLC has many applications in both laboratory and clinical science. It is a common technique used in pharmaceutical development, as it is a dependable way to obtain and ensure product purity. While HPLC can produce extremely high quality (pure) products, it is not always the primary method used in the production of bu... | 0 | Chromatography + Titration + pH indicators |
Traditionally, the Cohn process incorporating cold ethanol fractionation has been used for albumin purification. However, chromatographic methods for separation started being adopted in the early 1980s. Developments were ongoing in the time period between when Cohn fractionation started being used, in 1946, and when ... | 0 | Chromatography + Titration + pH indicators |
Thymol blue (thymolsulfonephthalein) is a brownish-green or reddish-brown crystalline powder that is used as a pH indicator. It is insoluble in water but soluble in alcohol and dilute alkali solutions.
It transitions from red to yellow at pH 1.2–2.8 and from yellow to blue at pH 8.0–9.6. It is usually a component of... | 0 | Chromatography + Titration + pH indicators |
Micellar liquid chromatography (MLC) is a form of reversed phase liquid chromatography that uses an aqueous micellar solutions as the mobile phase. | 0 | Chromatography + Titration + pH indicators |
Classical examples of polymorphism are the pair of minerals calcite and aragonite, both forms of calcium carbonate. Allotropy is the term used for elements, for example diamond versus graphite, and in metallurgy.
β-HgS precipitates as a black solid when Hg(II) salts are treated with HS. With gentle heating of the slur... | 1 | Crystallography |
Typical transparent media such as glasses are isotropic, which means that light behaves the same way no matter which direction it is travelling in the medium. In terms of Maxwell's equations in a dielectric, this gives a relationship between the electric displacement field D and the electric field E:
where ε is the per... | 1 | Crystallography |
An interstitial defect refers to additional atoms occupying some interstitial sites at random as crystallographic defects in a crystal which normally has empty interstitial sites by default. | 1 | Crystallography |
Past winners of the Martin Medal are:
* Robert Kennedy (2019)
* Jean-Luc Veuthey (2018)
* Andreas Manz (2017)
* Ian Wilson & Peter Myers (2016)
* Pavel Jandera (2015)
* Nobuo Tanaka (2014)
* Günther Bonn & Frantisek Svec (2013)
* Edward S. Yeung (2012)
* Peter J. Schoenmakers (2011)
* Peter Carr (2010)
* Wolfgang F. Li... | 0 | Chromatography + Titration + pH indicators |
Homoepitaxial growth of semiconductor thin films are generally done by chemical or physical vapor deposition methods that deliver the precursors to the substrate in gaseous state. For example, silicon is most commonly deposited from silicon tetrachloride (or germanium tetrachloride) and hydrogen at approximately 1200 t... | 1 | Crystallography |
Anthocyanins occur in the flowers of many plants, such as the blue poppies of some Meconopsis species and cultivars. Anthocyanins have also been found in various tulip flowers, such as Tulipa gesneriana, Tulipa fosteriana and Tulipa eichleri. | 0 | Chromatography + Titration + pH indicators |
Mathematically, a wallpaper group or plane crystallographic group is a type of topologically discrete group of isometries of the Euclidean plane that contains two linearly independent translations.
Two such isometry groups are of the same type (of the same wallpaper group) if they are the same up to an affine transform... | 1 | Crystallography |
In an anisotropic medium, such as a crystal, the polarisation field P is not necessarily aligned with the electric field of the light E. In a physical picture, this can be thought of as the dipoles induced in the medium by the electric field having certain preferred directions, related to the physical structure of the ... | 1 | Crystallography |
The stationary phase or adsorbent in column chromatography is a solid. The most common stationary phase for column chromatography is silica gel, the next most common being alumina. Cellulose powder has often been used in the past. A wide range of stationary phases are available in order to perform ion exchange chromato... | 0 | Chromatography + Titration + pH indicators |
GPC is often used to determine the relative molecular weight of polymer samples as well as the distribution of molecular weights. What GPC truly measures is the molecular volume and shape function as defined by the intrinsic viscosity. If comparable standards are used, this relative data can be used to determine molecu... | 0 | Chromatography + Titration + pH indicators |
Another use for the procedure is the affinity purification of antibodies from blood serum. If the serum is known to contain antibodies against a specific antigen (for example if the serum comes from an organism immunized against the antigen concerned) then it can be used for the affinity purification of that antigen. T... | 0 | Chromatography + Titration + pH indicators |
Ordinary (non-time) crystals form through spontaneous symmetry breaking related to a spatial symmetry. Such processes can produce materials with interesting properties, such as diamonds, salt crystals, and ferromagnetic metals. By analogy, a time crystal arises through the spontaneous breaking of a time-translation sym... | 1 | Crystallography |
Non-aqueous acid–base titrations can be carried out advantageously by thermometric means.
Acid leach solutions from some copper mines can contain large quantities of Fe(III) as well as Cu(II). The "free acid" (sulfuric acid) content of these leach solutions is a critical process parameter. While thermometric titrimetry... | 0 | Chromatography + Titration + pH indicators |
This technique is also used for detection of illicit drugs in various samples. The most common method of drug detection has been an immunoassay. This method is much more convenient. However, convenience comes at the cost of specificity and coverage of a wide range of drugs, therefore, HPLC has been used as well as an a... | 0 | Chromatography + Titration + pH indicators |
The thermospray (TSP) interface was developed in 1980 by Marvin Vestal and co-workers at the University of Houston. It was commercialized by Vestec and several of the major mass spectrometer manufacturers. The interface resulted from a long-term research project intended to find a LC–MS interface capable of handling hi... | 0 | Chromatography + Titration + pH indicators |
The subgroups discussed so far are not only infinite, they are also continuous (Lie groups). Any subgroup containing at least one non-zero translation must be infinite, but subgroups of the orthogonal group can be finite. For example, the symmetries of a regular pentagon consist of rotations by integer multiples of 72°... | 1 | Crystallography |
Crystal optics is the branch of optics that describes the behaviour of light in anisotropic media, that is, media (such as crystals) in which light behaves differently depending on which direction the light is propagating. The index of refraction depends on both composition and crystal structure and can be calculated u... | 1 | Crystallography |
The acceptable daily intake (ADI) is 0–4 mg/kg under both EU and WHO/FAO guidelines.
Sunset yellow FCF has no carcinogenicity, genotoxicity, or developmental toxicity in the amounts at which it is used.
It has been claimed since the late 1970s, under the advocacy of Benjamin Feingold, that sunset yellow FCF causes foo... | 0 | Chromatography + Titration + pH indicators |
In geometry, a glide reflection or transflection is a geometric transformation that consists of a reflection across a hyperplane and a translation ("glide") in a direction parallel to that hyperplane, combined into a single transformation. Because the distances between points are not changed under glide reflection, it ... | 1 | Crystallography |
In elution mode, solutes are applied to the column as narrow bands and, at low concentration, move down the column as approximately Gaussian peaks. These peaks continue to broaden as they travel, in proportion to the square root of the distance traveled. For two substances to be resolved, they must migrate down the co... | 0 | Chromatography + Titration + pH indicators |
The Ripper Method, developed in 1898, is an analytical chemistry technique used to determine the total amount of sulfur dioxide (SO) in a solution. This technique uses iodine standard and a starch indicator to titrate the solution and determine the concentration of free SO. The titration is done again with a new sample... | 0 | Chromatography + Titration + pH indicators |
In the hard sphere model, the particles are described as impenetrable spheres with radius ; thus, their center-to-center distance and they experience no interaction beyond this distance. Their interaction potential can be written as:
This model has an analytical solution in the Percus–Yevick approximation. Although hi... | 1 | Crystallography |
Before ion-exchange chromatography can be initiated, it must be equilibrated. The stationary phase must be equilibrated to certain requirements that depend on the experiment that you are working with. Once equilibrated, the charged ions in the stationary phase will be attached to its opposite charged exchangeable ions,... | 0 | Chromatography + Titration + pH indicators |
Crystal twinning occurs when two or more adjacent crystals of the same mineral are oriented so that they share some of the same crystal lattice points in a symmetrical manner. The result is an intergrowth of two separate crystals that are tightly bonded to each other. The surface along which the lattice points are shar... | 1 | Crystallography |
Phenol red exists as a red crystal that is stable in air. Its solubility is 0.77 grams per liter (g/L) in water and 2.9 g/L in ethanol. It is a weak acid with pK = 8.00 at .
A solution of phenol red is used as a pH indicator, often in cell culture. Its color exhibits a gradual transition from yellow (λ = 443 nm) to red... | 0 | Chromatography + Titration + pH indicators |
A crystal system is a set of point groups in which the point groups themselves and their corresponding space groups are assigned to a lattice system. Of the 32 crystallographic point groups that exist in three dimensions, most are assigned to only one lattice system, in which case both the crystal and lattice systems h... | 1 | Crystallography |
4-Nitrophenol (also called p-nitrophenol or 4-hydroxynitrobenzene) is a phenolic compound that has a nitro group at the opposite position of the hydroxyl group on the benzene ring. | 0 | Chromatography + Titration + pH indicators |
These are the crystallographic groups of a cubic crystal system: 23, 432, , 3m, and . All of them contain four diagonal 3-fold axes. These axes are arranged as 3-fold axes in a cube, directed along its four space diagonals (the cube has symmetry). These symbols are constructed the following way:
* First position – sym... | 1 | Crystallography |
Conductometric titration is a type of titration in which the electrolytic conductivity of the reaction mixture is continuously monitored as one reactant is added. The equivalence point is the point at which the conductivity undergoes a sudden change. Marked increase or decrease in conductance are associated with the c... | 0 | Chromatography + Titration + pH indicators |
The diffraction from a crystalline material, and thus the intensity of the diffracted beam, changes with the type and number of atoms inside the crystal unit cell. This fact is quantitatively expressed by the structure factor. Different materials have different structure factors, and similarly for different phases of t... | 1 | Crystallography |
ScBCSi (x = 0.030, y = 0.36 and z = 0.026) has a cubic crystal structure with space group F3m (No. 216) and lattice constant a = 2.03085(5) nm. This compound was initially identified as ScBC (phase I in the Sc-B-C phase diagram of figure 17). A small amount of Si was added into the floating zone crystal growth and thus... | 1 | Crystallography |
Chemical bleaching is achieved by oxidation or reduction. Oxidation can destroy the dye completely, e.g. through the use of sodium hypochlorite (NaClO, common bleach) or hydrogen peroxide. Reduction of methyl violet occurs in microorganisms but can be attained chemically using sodium dithionite. | 0 | Chromatography + Titration + pH indicators |
Retention uniformity, or R, is a concept in thin layer chromatography. It is designed for the quantitative measurement of equal-spreading of the spots on the chromatographic plate and is one of the Chromatographic response functions. | 0 | Chromatography + Titration + pH indicators |
Affinity chromatography can be used in a number of applications, including nucleic acid purification, protein purification from cell free extracts, and purification from blood.
By using affinity chromatography, one can separate proteins that bind to a certain fragment from proteins that do not bind that specific fragme... | 0 | Chromatography + Titration + pH indicators |
4-Nitrophenol can be prepared by nitration of phenol using dilute nitric acid at room temperature. The reaction produces a mixture of 2-nitrophenol and 4-nitrophenol. | 0 | Chromatography + Titration + pH indicators |
Foods and beverages contain numerous aromatic compounds, some naturally present in the raw materials and some forming during processing. GC–MS is extensively used for the analysis of these compounds which include esters, fatty acids, alcohols, aldehydes, terpenes etc. It is also used to detect and measure contaminants ... | 0 | Chromatography + Titration + pH indicators |
Reversed-phase liquid chromatography (RP-LC) is a mode of liquid chromatography in which non-polar stationary phase and polar mobile phases are used for the separation of organic compounds. The vast majority of separations and analyses using high-performance liquid chromatography (HPLC) in recent years are done using t... | 0 | Chromatography + Titration + pH indicators |
Paracetamol powder has poor compression properties, which poses difficulty in making tablets. A second polymorph was found with more suitable compressive properties. | 1 | Crystallography |
*This test is done to ascertain the nature of fluid in the vagina during pregnancy especially when premature rupture of membranes (PROM) is suspect. This test involves putting a drop of fluid obtained from the vagina onto paper strips containing nitrazine dye. The strips change color depending on the pH of the fluid. T... | 0 | Chromatography + Titration + pH indicators |
The problem of close-packing of spheres was first mathematically analyzed by Thomas Harriot around 1587, after a question on piling cannonballs on ships was posed to him by Sir Walter Raleigh on their expedition to America.
Cannonballs were usually piled in a rectangular or triangular wooden frame, forming a three-sid... | 1 | Crystallography |
The standard addition approach involves spiking the same sample extract with several known concentrations of analyte. This technique is more robust and effective than using matrix matched standards but is labor-intensive since each sample must be prepared several times to achieve a reliable calibration. | 0 | Chromatography + Titration + pH indicators |
When a second phase of mass fragmentation is added, for example using a second quadrupole in a quadrupole instrument, it is called tandem MS (MS/MS). MS/MS can sometimes be used to quantitate low levels of target compounds in the presence of a high sample matrix background.
The first quadrupole (Q1) is connected with a... | 0 | Chromatography + Titration + pH indicators |
Many beam HREM images of extremely thin samples are only directly interpretable in terms of a projected crystal structure if they have been recorded under special conditions, i.e. the so-called Scherzer defocus. In that case the positions of the atom columns appear as black blobs in the image (when the spherical aberra... | 1 | Crystallography |
Orcein, also archil, orchil, lacmus and C.I. Natural Red 28, are names for dyes extracted from several species of lichen, commonly known as "orchella weeds", found in various parts of the world. A major source is the archil lichen, Roccella tinctoria. Orcinol is extracted from such lichens. It is then converted to orce... | 0 | Chromatography + Titration + pH indicators |
Column chromatography in chemistry is a chromatography method used to isolate a single chemical compound from a mixture. Chromatography is able to separate substances based on differential adsorption of compounds to the adsorbent; compounds move through the column at different rates, allowing them to be separated into ... | 0 | Chromatography + Titration + pH indicators |
Oligocrystalline material owns a microstructure consisting of a few coarse grains, often columnar and parallel to the longitudinal ingot axis. This microstructure can be found in the ingots produced by electron beam melting (EBM). | 1 | Crystallography |
Ab initio or first principles calculations are any of a number of software packages making use of density functional theory to solve for the quantum mechanical state of a system. Perfect crystals are an ideal subject for such calculations because of their high periodicity. Since every simulation package will vary in ... | 1 | Crystallography |
In crystallography, the dyakis dodecahedron only exists in one crystal, which is pyrite. Pyrite has other forms other than the dyakis dodecahedron, including tetrahedra, octahedra, cubes and pyritohedra. Though the cube and octahedron are in the cubic crystal system, the dyakis dodecahedron and the pyritohedon are in ... | 1 | Crystallography |
Mass spectrometry (MS) is an analytical technique that measures the mass-to-charge ratio (m/z) of charged particles (ions). Although there are many different kinds of mass spectrometers, all of them make use of electric or magnetic fields to manipulate the motion of ions produced from an analyte of interest and determi... | 0 | Chromatography + Titration + pH indicators |
Vectors and planes in a crystal lattice are described by the three-value Miller index notation. This syntax uses the indices h, k, and ℓ as directional parameters.
By definition, the syntax (hkℓ) denotes a plane that intercepts the three points a/h, a/k, and a/ℓ, or some multiple thereof. That is, the Miller indices ar... | 1 | Crystallography |
Applications in macroscopic engineering have been suggested, building quasi-crystal-like large scale engineering structures, which could have interesting physical properties. Also, aperiodic tiling lattice structures may be used instead of isogrid or honeycomb patterns. None of these seem to have been put to use in pra... | 1 | Crystallography |
In geometry, the trihexagonal tiling is one of 11 uniform tilings of the Euclidean plane by regular polygons. It consists of equilateral triangles and regular hexagons, arranged so that each hexagon is surrounded by triangles and vice versa. The name derives from the fact that it combines a regular hexagonal tiling and... | 1 | Crystallography |
Bromocresol purple is used in medical laboratories to measure albumin. Use of BCP in this application may provide some advantage over older methods using bromocresol green. In microbiology, it is used for staining dead cells based on their acidity, and for the isolation and assaying of lactic acid bacteria.
In photogra... | 0 | Chromatography + Titration + pH indicators |
In gas chromatography, the Kovats retention index (shorter Kovats index, retention index; plural retention indices) is used to convert retention times into system-independent constants. The index is named after the Hungarian-born Swiss chemist Ervin Kováts, who outlined the concept in the 1950s while performing researc... | 0 | Chromatography + Titration + pH indicators |
To begin HPTLC, a stationary phase has to be determined to separate different compounds within a mixture. Around 90% of all pharmaceutical separations are performed on normal phase silica gel; however, other stationary phases such as alumina can be used for samples with dissociating compounds and cellulose for ionic co... | 0 | Chromatography + Titration + pH indicators |
A screw axis (helical axis or twist axis) is a line that is simultaneously the axis of rotation and the line along which translation of a body occurs. Chasles' theorem shows that each Euclidean displacement in three-dimensional space has a screw axis, and the displacement can be decomposed into a rotation about and a s... | 1 | Crystallography |
In crystallography, a fractional coordinate system (crystal coordinate system) is a coordinate system in which basis vectors used to the describe the space are the lattice vectors of a crystal (periodic) pattern. The selection of an origin and a basis define a unit cell, a parallelotope (i.e., generalization of a paral... | 1 | Crystallography |
Sphere packing in a cylinder is a three-dimensional packing problem with the objective of packing a given number of identical spheres inside a cylinder of specified diameter and length. For cylinders with diameters on the same order of magnitude as the spheres, such packings result in what are called columnar structure... | 1 | Crystallography |
Nucleation can be either homogeneous, without the influence of foreign particles, or heterogeneous, with the influence of foreign particles. Generally, heterogeneous nucleation takes place more quickly since the foreign particles act as a scaffold for the crystal to grow on, thus eliminating the necessity of creating a... | 1 | Crystallography |
An important application of mosaic crystals is in monochromators for x-ray and neutron radiation. The mosaicity enhances the reflected flux, and allows for some phase-space transformation.
Pyrolitic graphite (PG) can be produced in form of mosaic crystals (HOPG: highly ordered PG) with controlled mosaicity of up to a f... | 1 | Crystallography |
The distribution constant (or partition ratio) (K) is the equilibrium constant for the distribution of an analyte in two immiscible solvents.
In chromatography, for a particular solvent, it is equal to the ratio of its molar concentration in the stationary phase to its molar concentration in the mobile phase, also appr... | 0 | Chromatography + Titration + pH indicators |
*Karl Fischer titration: A potentiometric method to analyze trace amounts of water in a substance. A sample is dissolved in methanol, and titrated with Karl Fischer reagent (consists of iodine, sulfur dioxide, a base and a solvent, such as alcohol). The reagent contains iodine, which reacts proportionally with water. T... | 0 | Chromatography + Titration + pH indicators |
In manufacturing, the simulated moving bed (SMB) process is a highly engineered process for implementing chromatographic separation. It is used to separate one chemical compound or one class of chemical compounds from one or more other chemical compounds to provide significant quantities of the purified or enriched ma... | 0 | Chromatography + Titration + pH indicators |
Paper chromatography is one method for testing the purity of compounds and identifying substances. Paper chromatography is a useful technique because it is relatively quick and requires only small quantities of material. Separations in paper chromatography involve the principle of partition. In paper chromatography, su... | 0 | Chromatography + Titration + pH indicators |
The first electron crystallographic protein structure to achieve atomic resolution was bacteriorhodopsin, determined by Richard Henderson and coworkers at the Medical Research Council Laboratory of Molecular Biology in 1990. However, already in 1975 Unwin and Henderson had determined the first membrane protein structur... | 1 | Crystallography |
Shortly after the invention of the laser by Theodore Maiman in 1960, it was quickly recognized that a laser could act as a point source to evaporate source material in a vacuum chamber for fabricating thin films. In 1965, Smith and Turner succeeded in depositing thin films using a ruby laser, after which Groh deposite... | 1 | Crystallography |
Before MMC was considered as a chromatographic approach, secondary interactions were generally believed to be the main cause of peak tailing.
However, it was discovered afterwards that secondary interactions can be applied for improving separation power. In 1986, Regnier’s group synthesized a stationary phase that had ... | 0 | Chromatography + Titration + pH indicators |
Hydrion is a trademarked name for a popular line of compound pH indicators, marketed by Micro Essential Laboratory Inc., exhibiting a series of color changes (typically producing a recognizably different color for each pH unit) over a range of pH values. Although solutions are available, the most common forms of Hydrio... | 0 | Chromatography + Titration + pH indicators |
A microbatch usually involves immersing a very small volume of protein droplets in oil (as little as 1 µl). The reason that oil is required is because such low volume of protein solution is used and therefore evaporation must be inhibited to carry out the experiment aqueously. Although there are various oils that can b... | 1 | Crystallography |
For the special case of simple cubic crystals, the lattice vectors are orthogonal and of equal length (usually denoted a), as are those of the reciprocal lattice. Thus, in this common case, the Miller indices (hkℓ) and [hkℓ] both simply denote normals/directions in Cartesian coordinates.
For cubic crystals with lattice... | 1 | Crystallography |
The water content of most compounds can be determined with a knowledge of its formula. An unknown sample can be determined through thermogravimetric analysis (TGA) where the sample is heated strongly, and the accurate weight of a sample is plotted against the temperature. The amount of water driven off is then divided... | 1 | Crystallography |
There are three modes of formation of twinned crystals.
* Growth twins are the result of an interruption or change in the lattice during formation or growth due to a possible deformation from a larger substituting ion. Parallel growth describes a form of crystal growth that produces the appearance of a cluster of alig... | 1 | Crystallography |
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