A practical reference on Assay: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2025-12-28 and is reviewed periodically as new material appears.
Quality control for creatine monohydrate begins with identity confirmation and assay determination. Laboratories commonly use high-performance liquid chromatography with ultraviolet detection, often after derivatization or using a suitable column, to quantify creatine. Karl Fischer titration measures water content, which helps verify the monohydrate stoichiometry. Additional tests screen for heavy metals, residual solvents, and microbial contamination depending on the intended use. These tests establish composition and purity rather than biological effect.
Stability studies examine how creatine monohydrate changes under controlled temperature and humidity. The solid is generally stable when kept dry, but moisture can promote hydrolysis to creatinine, especially in solution or at elevated temperatures. Color, odor, and assay values are monitored over time to detect degradation. Because degradation pathways depend on storage conditions, shelf-life claims should specify the tested packaging, temperature, and humidity. Open questions remain about the long-term behavior of different crystal habits and particle sizes.
Regulatory treatment of creatine monohydrate varies by country and intended use. In some jurisdictions it is sold as a dietary supplement, while in others it may be treated as a food ingredient or a pharmaceutical raw material. Pharmacopeial monographs, where available, define identification, assay limits, and impurity thresholds. Manufacturers often follow these monographs or internal specifications to ensure batch-to-batch consistency. Analytical method validation is important because different methods can yield different apparent purity values if sample preparation or detection conditions are not controlled.
In animals, creatine is synthesized mainly in liver, kidney, and pancreas from arginine, glycine, and methionine. The first committed step transfers a guanidino group from arginine to glycine, forming guanidinoacetate. Subsequent methylation by S-adenosylmethionine yields creatine. Dietary sources include meat and fish; endogenous synthesis supplies part of the body pool. Most creatine is stored in skeletal muscle, where it is converted to phosphocreatine and participates in rapid regeneration of adenosine triphosphate during short, intense activity.
Commercial creatine products appear in several forms, including monohydrate, hydrochloride, citrate, nitrate, and ethyl ester. Creatine monohydrate is the most studied form and serves as a reference material in comparative research. Different forms vary in solubility, pH, and water content, but they share creatine as the active moiety after dissolution. Claims that one form is uniformly superior remain debated, and study designs often differ in population, exercise protocol, and outcome measures. Purity and hydration state are central to interpreting product labels.
Creatine monohydrate is the hydrated form of creatine, a nitrogen-containing organic acid involved in cellular energy transfer. Its molecular formula is C4H11N3O3, and it consists of creatine plus one water molecule in the crystal lattice. The anhydrous base, creatine, has the formula C4H9N3O2. The compound appears as a white, odorless, crystalline powder and is classified as a guanidine derivative. It is distinct from creatinine, a breakdown product measured in clinical chemistry.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | Creatine hydrate; N-carbamimidoyl-N-methylglycine monohydrate | Synonyms vary by naming convention |
| Typical assay method | HPLC-UV | Often paired with a reference standard |
| Water content method | Karl Fischer titration | Confirms monohydrate stoichiometry |
| Degradation product | Creatinine | Forms more readily in solution and with heat |
| Typical storage temperature | 15–25 °C | Keep dry and away from direct sunlight |
Creatine monohydrate is one of several solid forms of creatine described in the literature. Other forms include anhydrous creatine, creatine hydrochloride, and creatine ethyl ester, each with different solubility and stability characteristics. The monohydrate is distinct from creatinine, a spontaneous breakdown compound that forms when creatine loses water and cyclizes. Commercial descriptions sometimes use synonyms such as methylguanidoacetic acid or N-(aminoiminomethyl)-N-methylglycine, which refer to the same base molecule. These names appear in chemical databases and product labels.
Creatine monohydrate is a crystalline compound formed when one molecule of creatine binds with one molecule of water. Creatine itself is a nitrogen-containing organic acid involved in cellular energy transfer, particularly in muscle and nerve tissue. The monohydrate form is the most common solid form used in research and commercial products because it is relatively stable and easy to handle. Its molecular formula is C4H9N3O2·H2O, and its molar mass is about 149.15 grams per mole.
In the human body, creatine is synthesized mainly in the liver and kidneys from the amino acids glycine, arginine, and methionine. Dietary sources include meat, fish, and other animal tissues, which supply preformed creatine. Because plant foods contain little or no creatine, dietary intake varies widely among populations. The compound is stored largely in skeletal muscle, where it is converted to phosphocreatine and used to regenerate adenosine triphosphate during short bursts of activity.
Commercial creatine monohydrate is produced mainly by chemical synthesis rather than extraction from animal tissue. Suppliers provide a certificate of analysis listing assay, water content, and impurity limits, and some products undergo third-party testing. Verification of identity can use infrared or Raman spectroscopy alongside chromatographic methods. Storage recommendations generally call for a cool, dry place and a tightly closed container to limit moisture uptake. Open questions include how packaging, flavoring agents, and long-term storage affect the stability of finished products.
Dry creatine monohydrate is generally stable when kept sealed and protected from heat and moisture. In solution, however, creatine undergoes a slow cyclization to creatinine, a related compound with no role in phosphocreatine storage. The rate of this conversion increases with temperature and is influenced by pH. Because creatinine is a common impurity in liquid or poorly stored products, analytical testing often measures both compounds. The crystalline monohydrate is less prone to degradation than aqueous preparations, though caking can occur if moisture enters the container.
In Indonesia, the hardline anti-communist General Suharto wrested control from predecessor Sukarno in an attempt to establish a "New Order". From 1965 to 1966, with the aid of the US and other Western governments, the military led the mass killing of more than 500,000 members and sympathizers of the Indonesian Communist Party and other leftist organizations, and detained hundreds of thousands in prison camps under inhumane conditions. A top-secret CIA report stated that the massacres "rank as one of the worst mass murders of the 20th century, along with the Soviet purges of the 1930s, the Nazi mass murders during the Second World War, and the Maoist bloodbath of the early 1950s." These killings served US interests and constitute a major turning point in the Cold War as the balance of power shifted in Southeast Asia.
== 3D computer graphics == In 1996, Gibson received a research position at the Centre for Image and Sound Research at Simon Fraser University to study anaglyph images. He exhibited some of these images at the 1995 Currents exhibition in Vancouver and in Victoria, British Columbia. In 1996, he built the world's first completely anaglyphic website. Between 2002 and 2004, he studied 3D lenticular printing for his master's degree. By 2006 he was publicly showing autostereoscopic prints. In 2007 he had a major exhibition of this work at the 3D Center of Art and Photography in Portland, Oregon. In February 2011 he exhibited six large lenticular prints at the Blim Gallery in Vancouver, Canada. These prints paid homage to six renowned religious leaders by revealing the penis of God within them.
=== Literature === The medal for the Nobel Prize in Literature is given by the Swedish Academy. The reverse of the medal depicts a ' ... young man sitting under a laurel tree who, enchanted, listens to and writes down the song of the Muse'. The 1923 recipient of the literature medal, W. B. Yeats wrote in his 1925 book The Bounty of Sweden that the medal was " ... charming, decorative, academic design, French in manner, a work of the nineties. It shows a young man listening to a Muse, who stands young and beautiful with a great lyre in her hand, and I think as I examine it, 'I was good-looking once like that young man, but my unpractised verse was full of infirmity, my Muse old as it were; and now I am old and rheumatic, and nothing to look at, but my Muse is young". It is inscribed "Inventas vitam iuvat excoluisse per artes" ("It is beneficial to have improved (human) life through discovered arts") an adaptation of "inventas aut qui vitam excoluere per artes" from line 663 from book 6 of the Aeneid by the Roman poet Virgil. A plate below the figures is inscribed with the name of the recipient. The text "ACAD. SUEC." denoting the Swedish Academy is also inscribed on the reverse. It was designed by Erik Lindberg and is manufactured by Svenska Medalj in Eskilstuna.
Horst Christian Simco (born January 29, 1982), known professionally as Riff Raff (often stylized as RiFF RAFF), is an American rapper from Katy, Texas. He was originally managed by Swishahouse co-founder OG Ron C in 2011. After initially signing with Soulja Boy's record label Stacks on Deck Entertainment, Simco signed with producer Diplo's Mad Decent label to release his debut studio album, Neon Icon (2014). Despite mixed critical response, it moderately entered the Billboard 200 along with his second album Peach Panther (2016), which was released by Warner Records. Prior to the latter's release, Simco entered a US$4 million joint partnership with Stampede Management and BMG for his Neon Nation label and production company. The joint deal fell apart in the wake of legal disputes following the release of the 2012 film Spring Breakers. Simco was formerly a member of the hip hop group Three Loco, along with Andy Milonakis and Dirt Nasty, who reunited on his Balloween 2016 Halloween mixtape performing "Bitches in My Driveway". The trio premiered a Christmas parody song, "Ho-Ho-Loco", on the TBS Surprise! Instant Xmas Carol special. In February 2018, Riff Raff signed with singer Blackbear's Beartrap Sound for a reported US$500,000.
Sources: en.wikipedia.org
=== Membrane transport === Contrary to common belief, thyroid hormones cannot traverse cell membranes in a passive manner like other lipophilic substances. The iodine in o-position makes the phenolic OH-group more acidic, resulting in a negative charge at physiological pH. However, at least 10 different active, energy-dependent and genetically regulated iodothyronine transporters have been identified in humans. They guarantee that intracellular levels of thyroid hormones are higher than in blood plasma or interstitial fluids.
Scattering data is usually represented in terms of the so-called excess Rayleigh ratio defined as the Rayleigh ratio of the solution or single particle event from which is subtracted the Rayleigh ratio of the carrier fluid itself and other background contributions, if any. The Rayleigh Ratio measured at a detector lying at an angle θ and subtending a solid angle ΔΩ is defined as the intensity of light per unit solid angle per unit incident intensity, I0, per unit illuminated scattering volume ΔV. The scattering volume ΔV from which scattered light reaches the detector is determined by the detector's field of view generally restricted by apertures, lenses and stops. Consider now a MALS measurement made in a plane from a suspension of N identical particles/molecules per ml illuminated by a fine beam of light produced by a laser. Assuming that the light is polarized perpendicular to the plane of the detectors. The scattered light intensity measured by the detector at angle θ in excess of that scattered by the suspending fluid would be
In addition to providing flexibility and length, the poly dA portion of the linker also allows further purification of the mRNA-peptide fusion due to its high affinity for dT cellulose resin. The mRNA-peptide fusions can be selected over immobilized selection targets for several rounds with increasing stringency. After each round of selection, those library members that stay bound to the immobilized target are PCR amplified, and non-binders are washed off.
== Medical uses == Injectable fillers are widely used in cosmetics for soft tissue augmentation and facial rejuvenation. Their primary clinical applications include the correction of facial wrinkles and folds, restoration of age-related volume loss, and the enhancement of facial contours such as the lips, cheeks, and jawline. Hyaluronic acid-based fillers are commonly used for superficial and mid-dermal injections to treat fine lines and improve skin hydration, while more robust fillers are injected into deeper tissue layers to correct severe wrinkles and provide structural support. Biodegradable fillers, such as poly(lactic acid), can stimulate collagen production, contributing to longer-term volume effects. Injectable hydrogel-based fillers have been investigated for a wide range of medical applications due to their biocompatibility, injectability, and ability to form three-dimensional networks in situ. In wound healing, these materials provide a moist environment, act as barriers against infection, and conform to irregular tissue defects, thereby promoting tissue regeneration. They are also used to prevent post-operative adhesions by acting as physical barriers that separate tissues during healing, reducing fibrotic attachment. In hemostasis, injectable hydrogels can rapidly solidify at bleeding sites and adhere to tissues, enabling effective control of hemorrhage.
10 Minutes/10 Years: Your Definitive Guide to a Beautiful and Youthful Appearance. New York: Free Press. (2007) ISBN 978-0743297080 Age-less: The Definitive Guide to Botox, Collagen, Lasers, Peels, and Other Solutions for Flawless Skin. With Patricia Reynoso. New York: William Morrow. (2002); ISBN 978-0060516253
Sources: en.wikipedia.org
Berkelium is a soft, silvery-white, radioactive metal. The berkelium-249 isotope emits low-energy beta particles and thus is relatively safe to handle. It decays with a half-life of 330 days to californium-249, which is a strong emitter of ionizing alpha particles. This gradual transmutation is an important consideration when studying the properties of elemental berkelium and its chemical compounds, since the formation of californium brings not only chemical contamination, but also free-radical effects and self-heating from the emitted alpha particles.
== World War 2 == On 10 June 1940, with Italy's declaration of war on France and the United Kingdom, Calabria became involved in World War II. The civilian population immediately began to suffer from starvation and undernourishment, due to the lack of labor, low wages and inflation. Some foodstuffs were already rationed, while others, such as meat and sugar, could be found only on the black market. The large landowners took advantage, appropriating crops that were destined for storage and reselling them on the black market. Allied bombardments sapped civilian morale. On 3 September 1943, British and Canadian troops of the Eighth Army landed in Calabria in Operation Baytown, the first time that the Allies landed on the Italian mainland. Those landings were a feint and the main Allied blow came on 8 September 1943 with the landing of the American 5th Army at Salerno in Campania that was intended to cut off Mezzogiorno Axis forces. The Germans anticipated the Allies' plan, and as a consequence, relatively little fighting came in Calabria. Calabria troops mostly surrendered to the advancing British 5th Infantry Division and 1st Canadian Division; relatively few German forces were present. The main obstacle was the trail of destruction left by German combat engineers who systematically blew up bridges and destroyed roads and railroads as the Wehrmacht retreated north. On the day of the American landing, General Dwight Eisenhower announced on the radio that the Armistice of Cassibile had been signed on 3 September, ending all Italian resistance.
The methods and concepts presented in the Essai were further developed in later works, including Plantes équinoxiales which catalogued the thousands of plant specimens collected during his travels, many of them previously unknown to science. In the field of geology and climatology, Humboldt’s Recueil d’observations de zoologie et d’anatomie comparée and his monograph on the geology and climatology of South America offered comprehensive new perspectives. He was the first to produce geological cross-sections based on quantitative measurements, using barometric readings and the compass to map the structure and composition of mountain ranges and volcanic regions. His investigations of the Andes and Mexican volcanoes, including detailed studies of eruptions such as that of Jorullo, fostered a new understanding of vulcanism. Humboldt’s observations showed that volcanoes are often aligned along fissures in the earth’s crust, helping to shift geological thought away from Werner’s “neptunist” model toward a synthesis that recognized the role of internal heat and tectonic forces. His rigorous meteorological observations, employing thermometers, barometers, hygrometers, and magnetic instruments, produced the first reliable data on temperature, pressure, humidity, and magnetic phenomena across the Americas. Humboldt introduced the concept of isothermal lines—lines connecting points of equal mean temperature—making possible global comparisons of climate and advancing the study of climatology and physical geography.
== Mechanism of action == Inside cells, amifostine detoxifies reactive metabolites of platinum and alkylating agents, as well as scavenges free radicals. Other possible effects include accelerated DNA repair, induction of cellular hypoxia, inhibition of apoptosis, alteration of gene expression and modification of enzyme activity. Amifostine is believed to radioprotect normal tissue via Warburg-type effects.
=== Upregulation in stress === Production of high levels of heat shock proteins can also be triggered by exposure to different kinds of environmental stress conditions, such as infection, inflammation, exercise, exposure of the cell to harmful materials (ethanol, arsenic, and trace metals, among many others), ultraviolet light, starvation, hypoxia (oxygen deprivation), nitrogen deficiency (in plants) or water deprivation. As a consequence, the heat shock proteins are also referred to as stress proteins and their upregulation is sometimes described more generally as part of the cell stress response. The mechanism by which heat shock (or other environmental stressors) activates the heat shock factor has been determined in bacteria. During heat stress, outer membrane proteins (OMPs) do not fold and cannot insert correctly into the outer membrane. They accumulate in the periplasmic space. These OMPs are detected by DegS, an inner membrane protease, that passes the signal through the membrane to the sigmaE transcription factor. However, some studies suggest that an increase in damaged or abnormal proteins brings HSPs into action. Some bacterial heat shock proteins are upregulated via a mechanism involving RNA thermometers such as the FourU thermometer, ROSE element and the Hsp90 cis-regulatory element. Petersen and Mitchell found that in D.
Sources: en.wikipedia.org
Karl Fischer titration is a standard method for measuring water content in solid and liquid samples. The result helps confirm the expected monohydrate stoichiometry. Loss-on-drying can also indicate moisture but may not distinguish water from other volatile substances.
Creatinine forms through irreversible cyclization and loss of water from creatine, and the rate increases with temperature, moisture, and pH changes. In dry solid form, the reaction is slow. In solution, degradation can become noticeable over time.
A specification typically lists assay range, water content, appearance, identification, and limits for heavy metals, residual solvents, and microbial counts. It may also include particle size distribution or bulk density for handling purposes. These parameters are distinct from any claimed performance effect.
Creatine is the base compound, while creatine monohydrate includes one water molecule per creatine molecule in its crystal structure. The monohydrate form is common in supplements and analytical standards. The body uses creatine itself after the water is removed or dissociated.