HPLC comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2026-01-27. Numbers and descriptions here follow the published literature rather than marketing material.
Commercial creatine monohydrate is typically manufactured through chemical synthesis, often starting from sarcosine and cyanamide. The resulting material is crystallized, washed, and dried to a specified hydrate content. Finished lots are tested for identity, purity, moisture, and heavy metals before release. Because the compound can cyclize to creatinine under heat or prolonged storage in solution, manufacturers control temperature and humidity during processing. The solid itself is relatively stable when kept dry and sealed, but moisture uptake can cause caking and complicate accurate assay.
Analytical laboratories commonly identify creatine monohydrate by high-performance liquid chromatography with ultraviolet detection, often after dissolving the sample in water or dilute acid. Ion-exchange or reversed-phase columns separate creatine from creatinine and related guanidino compounds. Nitrogen content can be checked by Kjeldahl or combustion methods, while moisture is measured by Karl Fischer titration or loss on drying. These techniques give complementary views: chromatographic purity addresses related substances, whereas moisture and elemental data confirm hydrate stoichiometry. No single test defines quality by itself; a combination is used in specifications.
Storage recommendations generally emphasize a cool, dry place away from direct sunlight and strong oxidizers. Sealed containers limit humidity exchange, which helps prevent clumping and gradual conversion to creatinine. Long-term stability studies usually monitor appearance, moisture, and purity at intervals under defined temperature and humidity conditions. Accelerated tests at elevated temperature can reveal degradation pathways, but they do not perfectly predict room-temperature shelf life. Questions remain about how much creatinine formation is acceptable in different product categories and how packaging choices affect that rate over time.
Quality control for creatine monohydrate typically combines identity, assay, and impurity tests. High-performance liquid chromatography with ultraviolet detection is common for separating creatine from creatinine and related substances. Nuclear magnetic resonance and infrared spectroscopy can confirm molecular structure, while titration may assess acid-base content. Moisture content, heavy metals, residual solvents, and microbial limits are checked according to applicable standards. These tests help distinguish compliant material from powders that have degraded, been diluted, or contain manufacturing residues.
Handling practices aim to limit moisture uptake and thermal exposure. Containers should stay closed when not in use, and storage areas should avoid direct sunlight, strong heat, and high humidity. Caking can occur when powder absorbs water, even if the creatine itself has not fully degraded. Aqueous stock solutions are best prepared fresh when needed because they are less stable than the solid. Open questions include how different excipients, packaging materials, and climate conditions affect long-term stability across global supply chains.
Solid creatine monohydrate is relatively stable when kept dry and sealed, but heat and moisture accelerate its conversion to creatinine. This degradation involves intramolecular cyclization, a process that removes water and forms a less useful compound for phosphocreatine metabolism. Powder stored under cool, dry conditions can remain within specification for extended periods, though exact shelf life depends on packaging, humidity, and initial purity. Aqueous solutions degrade faster than dry powder, with pH and temperature influencing the rate. Because degradation is gradual, analytical testing is used to confirm potency at manufacture and during stability studies.
| Property | Value | Notes |
|---|---|---|
| Common analytical method | HPLC-UV | Separation from creatinine and related compounds. |
| Moisture content | Typically 12% theoretical | Monohydrate stoichiometry corresponds to about 12% water by mass. |
| Typical storage temperature | 15–25 °C | Cool, dry, sealed conditions limit moisture uptake. |
| Degradation marker | Creatinine | Formed by cyclization, especially in solution or with heat. |
| Solubility class | Moderately soluble in water | Solubility rises with temperature and varies with pH. |
Solid creatine monohydrate is generally stable when kept cool and dry, but it can hydrolyze to creatinine over time. Moisture, heat, and acidic conditions accelerate this conversion, which reduces assay values and changes the material's properties. Creatinine is a cyclic dehydration product that is also a normal human metabolite, so its presence in a sample is not necessarily a health concern by itself. In quality testing, creatinine is monitored as a marker of degradation and purity.
Identity and purity are assessed with several complementary methods. High-performance liquid chromatography can separate creatine from creatinine and related impurities, often with ultraviolet detection. Nuclear magnetic resonance and infrared spectroscopy provide structural confirmation, while Karl Fischer titration measures water content. Elemental analysis and mass spectrometry may be used for additional confirmation, especially in research or forensic settings. No single method captures every quality attribute, so laboratories typically combine results and compare them against a specification.
Creatine monohydrate is sold as a dietary ingredient in some countries and as a food supplement in others. Regulatory frameworks vary, so purity limits, labeling rules, and permitted claims are not globally uniform. In the United States, it falls under dietary supplement rules, whereas the European Union treats it as a food supplement ingredient. Pharmacopeial monographs, where they exist, can provide public quality standards, but not every product is required to meet them. Questions about long-term effects and patterns of use remain areas of active study rather than settled regulatory findings.
In aqueous solution, creatine monohydrate undergoes a slow conversion to creatinine, a cyclized degradation product. This reaction is pH- and temperature-dependent, and it proceeds faster in warm or alkaline conditions. Because the conversion is gradual, analytical measurements of creatine in solution must account for time and storage history. The equilibrium favors creatinine more strongly at higher temperatures, which is relevant to sample handling in laboratories and to beverage formulations. Refrigeration slows but does not entirely stop this process.
Quality assessment of creatine monohydrate typically uses high-performance liquid chromatography to separate creatine from creatinine and other impurities. Other methods include nuclear magnetic resonance spectroscopy, titration, and infrared spectroscopy for identity confirmation. Purity is often reported as a percentage of the labeled compound on a dry basis, while moisture content is measured separately. Because different analytical methods have different selectivity, comparing purity values across sources requires attention to the method and sample preparation.
In dry solid form, creatine monohydrate is relatively stable when protected from moisture and heat. The crystal lattice includes water, and exposure to high humidity can cause caking or gradual changes in powder flow. Elevated temperatures may accelerate decomposition, particularly if moisture is present. Studies generally report that sealed, dry material retains acceptable purity for extended periods, although exact shelf life depends on packaging and storage conditions. Light exposure is not usually considered a major factor for this compound.
=== Videos === 2010: Comedy Central Presents – DVD/download/streaming 2013: Mostly Sex Stuff (Comedy Central 2012) – DVD/download/streaming 2015: Live at the Apollo (HBO Home Video) – DVD/download/streaming 2017: The Leather Special (Netflix) – Streaming 2019: Growing (Netflix) – Streaming
Two other militiamen were identified as supporters of Daniela Carneiro's campaign. One of them is Cristiano de Oliveira Gouveia, known as Babu, who in a video posted on a social network appears with a sticker displaying Daniela's number. In addition, Babu appears on stage at a rally alongside Daniela and other candidates during the October elections. The other is Eduardo Araújo, a Belford Roxo councilor who was suspended after being appointed municipal secretary of Sustainable Energy of Belford Roxo. Eduardo participated in campaign motorcades with Daniela. The Public Prosecutor's Office says he was responsible for preventing the arrest of other members of the gang. Daniela Carneiro denied such involvement, stating that she does not condone "any illicit act" and that it is up to the courts to "judge and punish"; she also stated that she received support from numerous voters from various municipalities during her campaign. Deputy Marcelo Freixo, who gained notoriety by presiding over the CPI das Milícias in Rio de Janeiro, was appointed president of Embratur, an agency subordinate to the Ministry of Tourism. When questioned about the relationship, Freixo said that "it was up to her [Daniela] to speak about it" and that "my relationship with her is very recent, but very good and full of dialogue".
completes the withdrawal of their armed forces from Syria after being in the country since 2014. April 17 A federal appeals court allows the Trump administration to continue construction on the White House ballroom until at least June, in response to a lower court injunction ruling that the president requires congressional approval for the ballroom. Liz Conmy, a member of the North Dakota House of Representatives, dies in a plane crash in Brooklyn Park, Minnesota. April 18 – Reactions to the Iran War: During the Coachella festival, The Strokes denounce the US-Israel strikes against Iran and accuse the Central Intelligence Agency of using violence to promote regime change while performing Oblivius. April 19 – Eight children are killed and two other people are injured in a mass shooting at multiple locations in Shreveport, Louisiana. The perpetrator is killed by police. April 20 Labor Secretary Lori Chavez-DeRemer resigns amid abuse of power allegations. Keith E. Sonderling becomes the acting Secretary of Labor. Around 62 U.S. military veterans are arrested by the U.S. Capitol Police inside the United States Capitol in Washington, D.C. during a protest against the Iran war after occupying the Cannon House Office Building. Among those arrested are Center on Conscience & War executive director Mike Prysner and client Tyler Romero. The Onion implements a new plan to acquire InfoWars from far-right conspiracy theorist Alex Jones after an earlier plan was rejected by a judge. Tim Cook announces he will step down as Apple's CEO and become Executive Director.
Although designs and construction vary between brands, basic components of all ballpoint pens are universal. The making of a ballpoint pen, specially the tip, is considered a work of precision engineering. Standard components of a ballpoint tip include the freely rotating "ball" itself (distributing the ink on the writing surface), a "socket" holding the ball in place, small "ink channels" that provide ink to the ball through the socket, and a self-contained "ink reservoir" supplying ink to the ball. In modern disposable pens, narrow plastic tubes contain the ink, which is compelled downward to the ball by gravity. Brass, steel, or tungsten carbide are used to manufacture the ball bearing-like points, then housed in a brass socket. The function of these components can be observed at a larger scale in the ball-applicator of roll-on antiperspirant. The ballpoint tip delivers the ink to the writing surface while acting as a "buffer" between the ink in the reservoir and the air outside, preventing the quick-drying ink from drying inside the reservoir. Modern ballpoints are said to have a two-year shelf life, on average. A ballpoint tip that can write comfortably for a long period of time is not easy to produce, as it requires high-precision machinery and thin high-grade steel alloy plates. China, which as of 2017 produces about 80 percent of the world's ballpoint pens, relied on imported ballpoint tips and metal alloys before 2017.
Sources: en.wikipedia.org
As blood sugar testing for diagnosis of diabetes became more widespread, a curious side effect occurred: because blood sugar testing is not absolutely definitive in diagnoses of diabetes, more people were receiving borderline tests regarding their glycemic status. These borderline persons could be considered as being at risk for diabetes – prediabetic. Prediabetic patients have elevated blood sugar, but normal levels of sugar in their urine (glycosuria). Upjohn saw an opportunity to benefit and definitely market to a yet-greater expansion of the diabetic population, beyond even the "hidden diabetics" revealed by earlier public health campaigns. Upjohn also found a new use for Orinase: as a diagnostic. Orinase Diagnostic was added to the Orinase product line and, by 1962, was being sold as means of detecting prediabetes in that an abnormal response to Orinase following administration of cortisone in a "stress test" could be taken to indicate prediabetes. Orinase thus not only served to detect a previously hidden patient population, but also detected a patient population most likely to be interested in Orinase as a treatment for their newly diagnosed prediabetes. By the late 1960s, Orinase Diagnostic was withdrawn and the drug reverted to its therapeutic purpose. By that point, prediabetes had become a diagnosable and treatable condition which had dramatically increased the market for Orinase.
== Role in KLA == In 1993, Thaçi became a member of the inner circle of the KLA. The charisma of leaders such as Thaçi helped the KLA gain support from Kosovo Albanians. On 22 May 1993, together with Ilaz Kodra, Thaçi led an attack in Glogovac against Serbian police. The attack was a victory for the KLA; five officers were killed and two were injured. Thaçi (nom de guerre "Gjarpëri" − The Snake) was responsible for securing financial means and armaments, and training recruits in Albania to be dispatched to Kosovo. On 11 July 1997, Thaçi was tried in absentia and convicted by the district court in Pristina for terrorism associated with his activities in the KLA, and sentenced to 10 years in prison. Thaçi participated in the Battle of Rezalla, the KLA's first major battle, which occurred on 25 November. Many Yugoslav fighters were killed and their artillery and vehicles damaged after they were ambushed by KLA insurgents led by Adem Jashari. As a result, Yugoslav forces retreated to the village of Llausha where they shot two Albanian teachers who worked in the primary school of the village. In March 1999, Thaçi participated in the Rambouillet negotiations as the leader of the Kosovar Albanian team. Thaçi was perceived by western diplomats during the negotiations as the "voice of reason" within the KLA; his attendance demonstrated a willingness to accept autonomy for Kosovo within Serbia at a time when other rebel leaders rejected any solution short of full national independence.
== See also == Bruise, which is a hematoma caused by trauma Purpura secondary to clotting disorders Purpura hemorrhagica in horses Pigmented purpuric dermatosis Schamberg disease (progressive pigmentary purpura)
Sources: en.wikipedia.org
Hoyle, F.; Wickramasinghe, N.C. (1979). "Biochemical chromophores and the interstellar extinction at ultraviolet wavelengths". Astrophysics and Space Science. 65 (1): 241–244. Bibcode:1979Ap&SS..65..241H. doi:10.1007/BF00643503. S2CID 120184918. Hoyle, F.; Wickramasinghe, N.C.; Al-Mufti, S.; et al. (1982). "Infrared spectroscopy over the 2.9-3.9 μm waveband in biochemistry and astronomy". Astrophysics and Space Science. 83 (1–3): 405–409. Bibcode:1999Ap&SS.268..161H. doi:10.1023/A:1002417307802. Hoyle, F.; Wickramasinghe, N.C.; Al-Mufti, S. (1982). "Organo-siliceous biomolecules and the infrared spectrum of the Trapezium nebula". Astrophysics and Space Science. 86 (1): 63–69. Bibcode:1982Ap&SS..86...63H. doi:10.1007/BF00651830. S2CID 120249547. Hoyle, F.; Wickramasinghe, N.C. (1983). "Bacterial life in space". Nature. 306 (5942): 420. Bibcode:1983Natur.306..420H. doi:10.1038/306420a0. PMID 6646221. Hoyle, F. and Wickramasinghe, N.C., 1986. The case for life as a cosmic phenomenon, Nature 322, 509-511 Hoyle, F. and Wickramasinghe, N.C., 1990. Influenza – evidence against contagion, Journal of the Royal Society of Medicine 83. 258-261 Napier, W.M.; Wickramasinghe, J.T; Wickramasinghe, N.C. (2007). "The origin of life in comets". International Journal of Astrobiology. 6 (4): 321–323. Bibcode:2007IJAsB...6..321N. doi:10.1017/S1473550407003941. S2CID 121008660. Rauf, K.; Wickramasinghe, C. (2010). "Evidence for biodegradation products in the interstellar medium". International Journal of Astrobiology. 9 (1): 29–34. Bibcode:2010IJAsB...9...29R. doi:10.1017/S1473550409990334.
=== Calls for regulation and reform === The British Medical Association called for a formal mechanism to hold NHS managers and healthcare administrators accountable for mismanagement, comparable to the General Medical Council's ability to strike off doctors. A neonatal consultant who had raised concerns about Letby also urged the introduction of regulation for healthcare management. The Parliamentary and Health Service Ombudsman, Rob Behrens, said that radical reform of NHS management was needed to prevent similar failures. Dewi Evans called for an investigation into potential corporate manslaughter in relation to the case. Dame Ruth May, NHS England's Chief Nursing Officer, stated that the NHS was committed to learning from the case and welcomed the independent inquiry announced by the Department of Health and Social Care. On 21 August 2023, it was announced that the nursing director at the Countess of Chester Hospital during Letby's employment had been suspended from her subsequent role at Northern Care Alliance NHS Foundation Trust, following information that emerged during the trial. The Nursing and Midwifery Council later confirmed that she would face a fitness‑to‑practise investigation. She and other senior executives at the hospital were accused of failing to act on warnings about Letby.
=== Stress === Stress, to a physiologist, means any situation that threatens the continued stability of the body and its functions. Stress affects a wide variety of body systems: the two most consistently activated are the hypothalamic-pituitary-adrenal axis and the norepinephrine system, including both the sympathetic nervous system and the locus coeruleus-centered system in the brain. Stressors of many types evoke increases in noradrenergic activity, which mobilizes the brain and body to meet the threat. Chronic stress, if continued for a long time, can damage many parts of the body. A significant part of the damage is due to the effects of sustained norepinephrine release, because of norepinephrine's general function of directing resources away from maintenance, regeneration, and reproduction, and toward systems that are required for active movement. The consequences can include slowing of growth (in children), sleeplessness, loss of libido, gastrointestinal problems, impaired disease resistance, slower rates of injury healing, depression, and increased vulnerability to addiction.
An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Although the terms colloid and emulsion are sometimes used interchangeably, emulsion more narrowly refers to when both phases, dispersed and continuous, are liquids. In an emulsion, one liquid (the dispersed phase) is dispersed in the other (the continuous phase). Examples of emulsions include vinaigrettes, homogenized milk, liquid biomolecular condensates, and some cutting fluids for metal working. Two liquids can form different types of emulsions. As an example, oil and water can form, first, an oil-in-water emulsion, in which the oil is the dispersed phase, and water is the continuous phase. Second, they can form a water-in-oil emulsion, in which water is the dispersed phase and oil is the continuous phase. Multiple emulsions are also possible, including a "water-in-oil-in-water" emulsion and an "oil-in-water-in-oil" emulsion. Emulsions, being liquids, do not exhibit a static internal structure. The droplets dispersed in the continuous phase (sometimes referred to as the "dispersion medium") are usually assumed to be statistically distributed to produce roughly spherical droplets. The term "emulsion" is also used to refer to the photo-sensitive side of photographic film. Such a photographic emulsion consists of silver halide colloidal particles dispersed in a gelatin matrix.
Sources: en.wikipedia.org
Laboratories typically combine chromatographic separation with moisture and elemental analysis. High-performance liquid chromatography can quantify creatine and related substances such as creatinine. Moisture methods confirm the hydrate form and help detect excess water.
The dry crystalline solid is relatively stable when protected from moisture and heat. In solution, it can convert to creatinine over time, especially at higher temperatures. Storage conditions and product form influence the rate of change.
Moisture uptake can cause particles to stick together, particularly in humid conditions or after opening a container. Clumping does not necessarily mean the creatine has degraded. It can make accurate measuring more difficult, so dry storage and sealed packaging are used.
Keep it in a sealed container in a cool, dry place away from direct heat and moisture. Dry powder is more stable than prepared solutions.