The short version of HPLC-UV fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-11-02. Anything still debated is marked as such rather than presented as settled.
Creatine was first identified in skeletal muscle extracts in the nineteenth century, and its role in phosphagen energy buffering was clarified in the twentieth century. The monohydrate salt became widely studied after methods for inexpensive synthesis and crystallization were developed. Modern research examines its effects on muscle energetics, recovery, and cognitive performance under specific conditions. Findings vary with population, exercise protocol, baseline creatine status, and measurement method. Studies often compare supplementation with placebo during controlled training or testing schedules.
Creatine monohydrate is a hydrated form of creatine, a nitrogen-containing compound involved in cellular energy metabolism. Its molecular formula is C4H9N3O2·H2O, with a molar mass around 149.15 g/mol. The monohydrate is the most common solid form used in research and commercial settings because it crystallizes readily and remains stable under ordinary conditions. The term monohydrate indicates one water molecule per creatine molecule in the crystal lattice. It appears as a white crystalline powder with low odor.
Laboratory analysis of creatine monohydrate typically uses high-performance liquid chromatography to separate creatine from creatinine and other impurities. Detection may be ultraviolet, refractive index, or mass spectrometric, depending on the laboratory's equipment and the required sensitivity. Nuclear magnetic resonance spectroscopy can quantify the main component and identify related substances. Water content is measured by Karl Fischer titration, which is important because the monohydrate has a defined theoretical hydration level. Heavy metals, residual solvents, and microbial limits are also checked in quality control programs.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C4H9N3O2·H2O | Creatine plus one water molecule in the crystal lattice. |
| Molar mass | 149.15 g/mol | Calculated for the monohydrate form. |
| Appearance | White crystalline powder | Typical solid form; particle size can vary by processing. |
| Solubility class | Sparingly soluble in water | Dissolution improves with time, stirring, and temperature. |
| Common synonyms | Creatine hydrate; N-carbamimidoyl-N-methylglycine monohydrate | Names vary by chemical registry and supplier. |
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.
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.
==== Tests for pigments ==== In October 1978 a team of scientists affiliated with STURP took 32 samples from the surface of the Shroud, using adhesive tape. Of those samples, 18 were taken from areas of the Shroud that showed a body or blood image, while 14 were taken from non-image areas. The chemical microscopist Walter McCrone, a leading expert in the forensic authentication of historical documents and works of art, examined the tapes using polarized light microscopy and other physical and chemical techniques. McCrone concluded that the Shroud's body image had been painted with a dilute pigment of red ochre (a form of iron oxide) in a collagen tempera (i.e., gelatin) medium, using a technique similar to the grisaille employed in the 14th century by Simone Martini and other European artists. McCrone also found that the "bloodstains" in the image had been highlighted with vermilion (a bright red pigment made from mercury sulfide), also in a collagen tempera medium. McCrone reported that no actual blood was present in the samples taken from the Shroud. Other members of STURP rejected McCrone's conclusions and concluded, based on their own examination of the Shroud and the tape samples, that the image on the Shroud could not be explained by the presence of pigments. Mark Anderson, who was working for McCrone, analyzed the Shroud samples. In his book, chemist Raymond Rogers states that Anderson, who was McCrone's Raman microscopy expert, concluded that the samples acted as organic material when he subjected them to the laser.
Bukele began dating psychologist and former ballet dancer Gabriela Rodríguez in 2004 and the two married on 6 December 2014. The couple have two daughters. Their first was born in 2019 and their second in 2023.
=== House Minority Leader === In 2012, González was again re-elected, this time gathering the most votes overall, despite the fact that her party lost the majority of seats. The same night of the election, she was selected to become minority leader of her party.
Water chemistry analyses are carried out to identify and quantify the chemical components and properties of water samples. The type and sensitivity of the analysis depends on the purpose of the analysis and the anticipated use of the water. Chemical water analysis is carried out on water used in industrial processes, on waste-water stream, on rivers and stream, on rainfall and on the sea. In all cases the results of the analysis provides information that can be used to make decisions or to provide re-assurance that conditions are as expected. The analytical parameters selected are chosen to be appropriate for the decision-making process or to establish acceptable normality. Water chemistry analysis is often the groundwork of studies of water quality, pollution, hydrology and geothermal waters. Analytical methods routinely used can detect and measure all the natural elements and their inorganic compounds and a very wide range of organic chemical species using methods such as gas chromatography and mass spectrometry. In water treatment plants producing drinking water and in some industrial processes using products with distinctive taste and odors, specialized organoleptic methods may be used to detect smells at very low concentrations.
Sources: en.wikipedia.org
Pyruvic acid (CH3COCOOH) is the simplest of the alpha-keto acids, with a carboxylic acid and a ketone functional group. Pyruvate, the conjugate base, CH3COCOO−, is an intermediate in several metabolic pathways throughout the cell. Pyruvic acid can be made from glucose through glycolysis, converted back to carbohydrates (such as glucose) via gluconeogenesis, or converted to fatty acids through a reaction via acetyl-CoA. It can also be used to construct the amino acid alanine and can be converted into ethanol or lactic acid via fermentation. Pyruvic acid supplies energy to cells through the citric acid cycle (also known as the Krebs cycle) when oxygen is present (aerobic respiration), and alternatively ferments to produce lactate when oxygen is lacking.
(Indeed, testosterone, DHT, and estradiol levels are actually raised by bicalutamide treatment, and for this reason, levels of 3α- and 3β-androstanediol might be elevated to some degree similarly.) These metabolites of testosterone have been found to have AR-independent positive effects on sexual motivation, and may be involved in the preservation of sexual interest and function by bicalutamide and other NSAAs. However, a study found that a combination of bicalutamide and dutasteride, a 5α-reductase inhibitor and inhibitor of neurosteroid biosynthesis, produced fewer sexual side effects than GnRH analogue therapy, specifically suggesting the role of estradiol in the preservation sexual interest and function with bicalutamide monotherapy rather than of DHT metabolites. As an alternative possibility to testosterone metabolites preserving sexual desire and function with bicalutamide, it has been suggested that bicalutamide may not be able to block the actions of androgens in the brain to a degree sufficient to cause substantial sexual impairment.
Piłsudski signed the Soviet–Polish Non-Aggression Pact in 1932 and the German–Polish declaration of non-aggression in 1934, but in 1933 he insisted that there was no threat from the East or West and said that Poland's politics were focused on becoming fully independent without serving foreign interests. He initiated the policy of maintaining an equal distance and an adjustable middle course regarding the two great neighbors, later continued by Józef Beck. Piłsudski kept personal control of the army, but it was poorly equipped, poorly trained and had poor preparations in place for possible future conflicts. His only war plan was a defensive war against a Soviet invasion.[r] The slow modernization after Piłsudski's death fell far behind the progress made by Poland's neighbors and measures to protect the western border, discontinued by Piłsudski from 1926, were not undertaken until March 1939. Sanation deputies in the Sejm used a parliamentary maneuver to abolish the democratic March Constitution and push through a more authoritarian April Constitution in 1935; it reduced the powers of the Sejm, which Piłsudski despised. The process and the resulting document were seen as illegitimate by the anti-Sanation opposition, but during World War II, the Polish government-in-exile recognized the April Constitution in order to uphold the legal continuity of the Polish state.
=== Cancer === Meta-analyses have been performed to examine the association between NQO1 polymorphism and increased cancer risk. The results from some of these analyses have been summarized in the table below:
== Introduction == Theoretical calculation for the proton and neutron drip lines show that there would be about 7,000 nuclides that are between the drip lines, and containing 2 to 120 protons. There are presently 251 known stable nuclides. Many of these in theory could decay through spontaneous fission, alpha decay, double beta decay, etc. with a very long half-life, but this has not yet been observed. Thus, the number of stable nuclides is subject to change if some of these 251 have radioactive decay observed in the future. In this article, the "stable" nuclides are divided into three tables: one for nuclides that are theoretically stable (meaning no decay mode is possible) except to spontaneous fission, which is not considered plausible in this mass range; one for nuclides that can theoretically undergo forms of decay other than spontaneous fission but have no published lower bound on lifetime from experimental evaluations; and one for nuclides that can theoretically decay and have been examined without detecting any decay, allowing a lower bound to be published. In this last table, where a decay has been predicted theoretically but never observed experimentally (either directly or by finding an excess of the daughter), the theoretical decay mode is given in parentheses, and "> (lifetime in years)" is shown in the half-life column to show this lower limit in scientific notation. Such nuclides are considered to be "stable", also called "observationally stable" indicating the tentative nature of the conclusion, until some decay has been observed.
Sources: en.wikipedia.org
Creatine is the base compound, while creatine monohydrate is a solid crystalline form that contains one water molecule per creatine molecule. Once dissolved, the monohydrate dissociates and releases creatine, which can participate in cellular energy metabolism. The monohydrate is the form most commonly used in research and commercial products.
Meat and fish contain creatine, and the human body also synthesizes it from amino acids. The monohydrate form is not a natural food ingredient as such; it is a manufactured crystalline solid that provides creatine after ingestion. Food sources contribute to total body creatine stores alongside endogenous synthesis.
It means the crystal lattice includes one molecule of water for each molecule of creatine. This water is part of the solid's ordered structure, not bulk moisture. The hydrate form influences properties such as solubility, density, and shelf stability.
Purity testing often uses high-performance liquid chromatography to measure creatine and creatinine. Water content can be checked by Karl Fischer titration. Additional tests may cover heavy metals, residual solvents, and microbial contamination.