HPLC-UV 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 2025-12-21. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
| 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 |
This settlement, boycotted by the PF and rejected internationally, led to multiracial elections and Rhodesia's reconstitution under majority rule as Zimbabwe Rhodesia in June 1979. Muzorewa, the electoral victor, took office as the country's first black prime minister at the head of a coalition cabinet comprising 12 blacks and five whites, including Smith as minister without portfolio. Dismissing Muzorewa as a "neocolonial puppet", ZANLA and ZIPRA continued their armed struggle until December 1979, when Whitehall, Salisbury and the Patriotic Front settled at Lancaster House. Muzorewa's government revoked UDI, thereby ending the country's claim to be independent after 14 years, and dissolved itself. The UK suspended the constitution and vested full executive and legislative powers in a new Governor, Lord Soames, who oversaw a ceasefire and fresh elections during February and March 1980. These were won by ZANU, whose leader Robert Mugabe became Prime Minister when the UK granted independence to Zimbabwe as a republic within the Commonwealth in April 1980. African nationalist politicians continued to cite their opposition to the UDI as a means of legitimising their rule of Zimbabwe into the 21st century. Since it was issued, the UDI has been recounted in scholarly literature, autobiographies of those involved in its creation, and works of fiction.
Stevens–Johnson syndrome (SJS) is a type of severe skin reaction. Together with toxic epidermal necrolysis (TEN) and Stevens–Johnson/toxic epidermal necrolysis (SJS/TEN) overlap, they are considered febrile mucocutaneous drug reactions and probably part of the same spectrum of disease, with SJS being less severe. Erythema multiforme (EM) is generally considered a separate condition. Early symptoms of SJS include fever and flu-like symptoms. A few days later, the skin begins to blister and peel, forming painful raw areas. Mucous membranes, such as the mouth, are also typically involved. Complications include dehydration, sepsis, pneumonia and multiple organ failure. The most common cause is certain medications such as lamotrigine, carbamazepine, allopurinol, sulfonamide antibiotics and nevirapine. Other causes can include infections such as Mycoplasma pneumoniae and cytomegalovirus, or the cause may remain unknown. Risk factors include HIV/AIDS and systemic lupus erythematosus. The diagnosis of Stevens–Johnson syndrome is based on involvement of less than 10% of the skin. It is known as TEN when more than 30% of the skin is involved and considered an intermediate form when 10–30% is involved. SJS/TEN reactions are believed to follow a type IV hypersensitivity mechanism. It is also included with drug reaction with eosinophilia and systemic symptoms (DRESS syndrome), acute generalized exanthematous pustulosis (AGEP) and toxic epidermal necrolysis in a group of conditions known as severe cutaneous adverse reactions (SCARs).
the act was of such a lewd character as to outrage public decency; this element constitutes the nature of the act, which has to be proved before the offence can be established, and the act took place in a public place and must have been capable of being seen by two or more persons who were actually present, even if they did not actually see it. The mens rea of this offence can be satisfied if the defendant intentionally does an act which outrages public decency, regardless of one's state of mind. Judge Peter Rook QC and Robert Ward suggest that obiter dicta in cases such as R v Thallman (1863) 9 Cox CC 388 indicate that the requirement of a "public place" may be falling out of favour, due to its vagueness and redundancy to the requirement for two potential witnesses. In R v Hamilton [2007] EWCA Crim 2062 an act of upskirting in public went undetected until a police search discovered indecent images. It was held that it was immaterial whether a person had actually seen the act, provided it was capable of being seen by at least two persons. Previous cases had all been seen, but this was held to be a matter of evidence, not an element of the offence.
The stability of nuclei quickly decreases with the increase in atomic number after curium, element 96, whose most stable isotope, 247Cm, has a half-life four orders of magnitude longer than that of any subsequent element. All nuclides with an atomic number above 101 undergo radioactive decay with half-lives shorter than 30 hours. No elements with atomic numbers above 82 (after lead) have stable isotopes. This is because of the ever-increasing Coulomb repulsion of protons, so that the strong nuclear force cannot hold the nucleus together against spontaneous fission for long. Calculations suggest that in the absence of other stabilizing factors, elements with more than 104 protons should not exist. However, researchers in the 1960s suggested that the closed nuclear shells around 114 protons and 184 neutrons should counteract this instability, creating an island of stability in which nuclides could have half-lives reaching thousands or millions of years. While scientists have still not reached the island, the mere existence of the superheavy elements (including oganesson) confirms that this stabilizing effect is real, and in general the known superheavy nuclides become exponentially longer-lived as they approach the predicted location of the island. Oganesson is radioactive, decaying via alpha decay and spontaneous fission, with a half-life that appears to be less than a millisecond. Nonetheless, this is still longer than some predicted values.
Sources: en.wikipedia.org
Decarboxylation is a chemical reaction that removes a carboxyl group and releases carbon dioxide (CO2). Usually the term refers to a reaction of carboxylic acids, removing a carbon atom from a carbon chain. The reverse process, which is the first chemical step in photosynthesis, is called carboxylation, the addition of CO2 to a compound. Enzymes that catalyze decarboxylations are called decarboxylases or, more formally, carboxy-lyases (EC number 4.1.1).
== History == The law was named after scientist Jacques Charles, who formulated the original law in his unpublished work from the 1780s. In two of a series of four essays presented between 2 and 30 October 1801, John Dalton demonstrated by experiment that all the gases and vapours that he studied expanded by the same amount between two fixed points of temperature. The French natural philosopher Joseph Louis Gay-Lussac confirmed the discovery in a presentation to the French National Institute on 31 Jan 1802, although he credited the discovery to unpublished work from the 1780s by Jacques Charles. The basic principles had already been described by Guillaume Amontons and Francis Hauksbee a century earlier. Dalton was the first to demonstrate that the law applied generally to all gases, and to the vapours of volatile liquids if the temperature was well above the boiling point. Gay-Lussac concurred. With measurements only at the two thermometric fixed points of water (0°C and 100°C), Gay-Lussac was unable to show that the equation relating volume to temperature was a linear function. On mathematical grounds alone, Gay-Lussac's paper does not permit the assignment of any law stating the linear relation. Both Dalton's and Gay-Lussac's main conclusions can be expressed mathematically as:
Liquid and solid carbon dioxide are important refrigerants, especially in the food industry, where they are employed during the transportation and storage of ice cream and other frozen foods. Solid carbon dioxide is called "dry ice" and is used for small shipments where refrigeration equipment is not practical. Solid carbon dioxide is always below −78.5 °C (−109.3 °F) at regular atmospheric pressure, regardless of the air temperature. Liquid carbon dioxide (industry nomenclature R744 or R-744) was used as a refrigerant prior to the use of dichlorodifluoromethane (R12, a chlorofluorocarbon (CFC) compound). CO2 might enjoy a renaissance because one of the main substitutes to CFCs, 1,1,1,2-tetrafluoroethane (R134a, a hydrofluorocarbon (HFC) compound) contributes to climate change more than CO2 does. CO2 physical properties are highly favorable for cooling, refrigeration, and heating purposes, having a high volumetric cooling capacity. Due to the need to operate at pressures of up to 130 bars (1,900 psi; 13,000 kPa), CO2 systems require highly mechanically resistant reservoirs and components that have already been developed for mass production in many sectors. In automobile air conditioning, in more than 90% of all driving conditions for latitudes higher than 50°, CO2 (R744) operates more efficiently than systems using HFCs (e.g., R134a). Its environmental advantages (GWP of 1, non-ozone depleting, non-toxic, non-flammable) could make it the future working fluid to replace current HFCs in cars, supermarkets, and heat pump water heaters, among others.
=== Screening glucose challenge test === The screening glucose challenge test (sometimes called the O'Sullivan test) is performed between 24 and 28 weeks and can be seen as a simplified version of the oral glucose tolerance test (OGTT). No previous fasting is required for this screening test, in contrast to the OGTT. The O'Sullivan test involves drinking a solution containing 50 grams of glucose and measuring blood levels one hour later. If the cut-off point is set at 140 mg/dL (7.8 mmol/L), 80% of women with GDM will be detected. If this threshold for further testing is lowered to 130 mg/dL, 90% of GDM cases will be detected, but there will also be more women who will be subjected to a consequent OGTT unnecessarily.
68Ga DOTA-TATE (gallium-68 dotatate, GaTate) is used to measure tumor SSR density and whole-body bio-distribution via PET imaging. 68Ga DOTA-TATE imagery has a much higher sensitivity and resolution compared to 111In octreotide gamma camera or SPECT scans, due to intrinsic modality differences. It is commonly used to confirm the presence of paragangliomas and pheochromocytomas.
Sources: en.wikipedia.org
== History == Salad and Go was founded in 2013 in Gilbert, Arizona by Tony and Roushan Christofellis. The co-founders asked Chef Daniel Patino to help them develop the concept. Chef Patino remains an executive chef for the brand. In March 2022, industry veteran Charlie Morrison joined Salad and Go as Chief Executive Officer (CEO). Since Morrison joined, the brand has expanded rapidly into major markets including the Dallas–Fort Worth metroplex, Houston, Las Vegas and Oklahoma City while continuing to open locations in its home state of Arizona. Salad and Go was on track to have a total of 135 stores open by the end of 2023. In January 2024, CEO Charlie Morrison said it was on pace to continue to open up a restaurant a week and described his plans for thousands of locations. On September 19, 2025, Salad and Go closed all stores in Houston, San Antonio, and Austin, along with some in North Texas, with a total of 41 closures. New CEO Mike Tattersfield stated the move was to focus on more disciplined growth. In January 2026, Salad and Go announced it would be closing all its remaining Texas and Oklahoma locations and focusing on strengthening its operations in Arizona and Nevada. The company also announced it would be relocating its headquarters from Coppell, Texas, back to the Phoenix area. On August 4, 2026, Salad and Go filed for Chapter 11 bankruptcy protection and announced the permanent closure of all remaining locations effective the next day, August 5. As a result, plans for the new headquarters were scrapped.
The active Ras protein phosphorylates several proteins, along with the serine/threonine kinase, Raf. Raf in turn activates the MAPK cascade to facilitate ribosomal s6 kinase (RSK) activation and transcriptional regulation. Both Akt and RSK, components of the PI3K-Akt and MAPK pathways respectively, act to phosphorylate the cyclic AMP response element binding protein (CREB) transcription factor. Phosphorylated CREB translocates into the nucleus and mediates increased expression of anti-apoptotic proteins, thus promoting NGF-mediated cell survival. However, in the absence of NGF, the expression of pro-apoptotic proteins is increased when the activation of cell death-promoting transcription factors such as c-Jun are not suppressed by the aforementioned NGF-mediated cell survival pathways.
In 2009, the indications were expanded to include the prophylaxis of transplant rejection in adult and paediatric, kidney, liver or heart allograft recipients and the treatment of allograft rejection resistant to treatment with other immunosuppressive medicinal products in adults and children.
On February 21, 2013, Eisold announced that Justin Benoit, a former live contributor to Cold Cave, had died. In support of the new singles, Cold Cave embarked on an extensive tour of Asia, performing in Japan, South Korea, China, Thailand, Nepal, and Hong Kong in April 2013; performed live with industrial/noise pioneer Boyd Rice in mid-2013; toured with synthpop artist Gary Numan in September 2013; and toured with Nitzer Ebb frontman Douglas McCarthy in October 2013. In January 2014, Cold Cave remixed the song "Running" by Nine Inch Nails as part of a remix EP Seed Eight, to coincide with the launch of Beats Music. In May 2014, Cold Cave opened for Nine Inch Nails on their full European and UK tour. They were also invited to open for Nine Inch Nails and Soundgarden on their North American tour, after Death Grips, the band originally chosen for opening, decided to split. Cold Cave began working on its third studio album and follow up to Cherish the Light Years tentatively titled Sunflower in 2013, and a release date in 2014 was originally anticipated. On what the potential sonic direction of the new album, Eisold said it would be a "mix between some of the bigger sounds on Cherish and more minimal stuff I'm interested in now, like Suicide or 39 Clocks." However tours in support of Full Cold Moon and the 2012–2013 singles series proved to be more fruitful than anticipated, and as a result, work on Sunflower was put on hold. In June 2015, Cold Cave performed at the wedding of Tony Hawk and Catherine Goodman at the Adare Manor in Ireland.
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.
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.