mass spectrometry 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.
Last reviewed on 2026-03-03. Where a claim depends on a specific study, the study is described rather than over-claimed.
The compound is registered in Russia as a pharmaceutical product, most commonly formulated as a nasal solution, and has been used in that setting since the 1990s. Outside that jurisdiction it is generally handled as a research chemical rather than an approved medicine. Regulatory status therefore differs sharply between countries, and material sold internationally may not correspond to the Russian pharmaceutical formulation. Documentation with commercial samples is typically limited to a certificate of analysis covering purity and identity, not clinical status or local legal classification.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It corresponds to the ACTH(4-7) fragment extended at the C-terminus by a Pro-Gly-Pro tripeptide, an addition intended to slow enzymatic breakdown. The molecular formula is C37H51N9O10S and the molecular mass is approximately 814 daltons. In the literature it is often described as an ACTH(4-10) analog, although that label reflects a naming convention as much as a precise structural relationship. The compound was developed in Russia and remains most closely associated with that research tradition.
Laboratory descriptions of the material are consistent across suppliers. It appears as a white to off-white lyophilized powder that dissolves readily in water and in polar organic solvents such as dimethyl sulfoxide. Aqueous solutions are clear and colorless at low concentrations. Because the peptide contains methionine, oxidation at the sulfur atom is a recognized degradation pathway, and handling notes usually call for protected, desiccated storage. Reported purity for research-grade lots is generally above 95 percent as measured by reversed-phase high-performance liquid chromatography.
Once dissolved, the peptide is considerably less stable than the solid. Aqueous solutions are usually prepared at neutral to slightly acidic pH, filtered, and divided into single-use aliquots before freezing. Repeated freeze-thaw cycles are a common cause of avoidable loss and are best prevented by never refreezing a thawed aliquot. Adsorption to plastic and glass surfaces can lower the measured concentration of dilute solutions, particularly below roughly 0.1 mg/mL. Buffer choice, salt content, and container material all influence how much peptide remains detectable after storage.
Identity and purity are established with standard peptide methods. Reversed-phase HPLC with ultraviolet detection near 214 nm resolves the parent peak from deletion and truncation byproducts, and reports typically quote a main-peak percentage. Mass spectrometry by electrospray or MALDI-TOF confirms the expected molecular mass, while amino acid analysis or peptide mapping can verify composition when the sequence itself is in question. A certificate of analysis that pairs a chromatogram with a mass spectrum is more informative than a purity figure alone. Counter-ion content and residual solvents are separate specifications and are frequently omitted.
Semax is normally supplied as a lyophilized powder, and that form is the most stable. Suppliers commonly recommend storage at -20 °C in a desiccated container protected from light, with short-term handling at room temperature limited to weighing and transfer. Powder that has absorbed moisture degrades faster, so vials should be warmed to ambient temperature before opening to prevent condensation on the contents. Hygroscopic behavior is typical of short hydrophilic peptides, and humidity control matters more than temperature alone for long-term retention.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Contains one methionine sulfur atom |
| Molecular mass | Approximately 814 Da | Consistent with a seven-residue peptide |
| Appearance | White to off-white powder | Typical lyophilized form |
| Solubility | Freely soluble in water | Also soluble in dimethyl sulfoxide |
| Typical storage | -20 °C, desiccated | Limits methionine oxidation |
Scientific literature on semax is unevenly distributed. A substantial share of published work originates from a small number of laboratories in Russia, while independent replication elsewhere is limited. Human data consist mostly of small trials with short follow-up, and several reported outcomes rely on subjective rating scales. Questions about how much intact peptide reaches the central nervous system after nasal administration, and how long it persists there, are still unresolved. The compound is best described as an active research subject rather than a settled pharmacological agent.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It was derived from the ACTH(4-10) fragment, a short segment of adrenocorticotropic hormone that lacks the hormonal activity associated with the full-length peptide. Researchers at the Institute of Molecular Genetics in Moscow developed the compound during the 1980s. It has been registered as a pharmaceutical product in Russia and several neighbouring countries, where it is supplied as a nasal solution, and it is also sold internationally as a research chemical.
Claims about enhanced focus, memory, or mood in healthy people rest mostly on anecdotal reports and community discussion rather than on controlled data. It remains unclear whether any cognitive benefit observed in patients recovering from brain injury would extend to uninjured users. Dose-response relationships, long-term safety, and interactions with other drugs are not well characterized in the peer-reviewed literature. Questions about optimal route of administration and treatment duration likewise remain open.
Semax binds to melanocortin receptors and is thought to influence neuronal survival and plasticity rather than to act through the adrenal axis. Laboratory work has shown increased expression of brain-derived neurotrophic factor and nerve growth factor in treated tissue. Changes in c-Fos, a marker of neuronal activation, have also been reported. Because the peptide is rapidly degraded by peptidases, its effects are generally attributed to downstream signaling cascades rather than to sustained receptor occupancy.
研究兴趣主要集中在神经营养因子相关的路径上，包括脑源性神经营养因子与神经生长因子的表达变化。部分实验报告称在特定条件下观察到这些因子的水平上升，但具体信号通路和剂量依赖关系仍未完全厘清。多数公开数据来自细胞模型和动物实验，人体对照研究数量有限。因此，该化合物的作用机制在文献中属于活跃讨论，而非已经确立的定论。
Semax 是一种人工合成的七肽，氨基酸序列为 Met-Glu-His-Phe-Pro-Gly-Pro，单字母缩写记作 MEHFPGP。它被归类为促肾上腺皮质激素片段 ACTH(4-10) 的结构类似物，但并不天然存在于生物体内。母体片段 ACTH(4-10) 的序列为 Met-Glu-His-Phe-Arg-Trp-Gly，Semax 替换了中间两个残基，并在羧基端延长了 Pro-Gly-Pro 三肽。这种延长被普遍认为能提升分子对肽酶的耐受性。
该化合物于二十世纪八十年代在俄罗斯被开发，相关工作由俄罗斯科学院分子遗传学研究所的研究团队主导。开发目标并非复制 ACTH 的完整激素活性，而是寻找保留其神经作用方向、同时去除促肾上腺皮质激素释放效应的短肽片段。研究记录显示，这一方向促成了多个相关短肽的合成与筛选，而 Semax 是其中被研究最广泛的一个。当地文献常以 Семакс 这一名称指代它。
Routine characterization relies on reversed-phase high-performance liquid chromatography to establish purity and on mass spectrometry to confirm molecular identity. Electrospray ionization and matrix-assisted laser desorption ionization are both used for mass verification. Amino acid analysis and peptide mapping can detect sequence errors. Common impurities include truncated sequences, methionine sulfoxide formed by oxidation, and deamidated products. Chromatograms are usually recorded near 214 nm, where the peptide backbone absorbs, and purity is reported as the percentage area of the principal peak.
Verification of a supplied batch generally combines a certificate of analysis with independent testing, because certificates are self-reported documents. A typical package includes a chromatographic trace, a mass spectrum, and a stated water or counter-ion content. Batch-to-batch consistency matters more than a single purity figure when results are compared across experiments. No single mandatory standard governs research-grade peptide release, so laboratories are expected to define their own acceptance criteria. Residual trifluoroacetate from purification is a frequently overlooked counter-ion.
Lyophilized material is chemically stable for extended periods when kept dry, cold, and protected from light. The powder is hygroscopic, so vials should be warmed to room temperature before opening to reduce condensation on the contents. Once dissolved, the peptide is far less stable because peptide bonds are susceptible to hydrolysis and the methionine residue can oxidize. Solutions are typically aliquoted and held at 2-8 °C for short intervals or frozen for longer ones, and repeated freeze-thaw cycles should be avoided.
=== Topical/symptomatic === Topical treatment for the skin changes of scleroderma do not alter the disease course, but may improve pain and ulceration. A range of nonsteroidal anti-inflammatory drugs, such as naproxen, can be used to ease painful symptoms. The benefit from steroids such as prednisone is limited. Episodes of Raynaud's phenomenon sometimes respond to nifedipine or other calcium channel blockers; severe digital ulceration may respond to prostacyclin analogue iloprost, and the dual endothelin-receptor antagonist bosentan may be beneficial for Raynaud's phenomenon. Skin tightness may be treated systemically with methotrexate and ciclosporin. and the skin thickness can be treated with penicillamine.
=== Commonly affected body areas === Commonly affected areas in autoimmune diseases include blood vessels, connective tissues, joints, muscles, red blood cells, skin, and endocrine glands such as the thyroid gland (in diseases like Hashimoto's thyroiditis and Graves' disease) and the pancreas (in type 1 diabetes). The impacts of these diseases can range from localized damage to certain tissues, alteration in organ growth and function, to more systemic effects when multiple tissues throughout the body are affected.
== Integrins == Integrins function as the major cell receptor for extracellular matrix protein. These receptors comprise an α and β transmembrane subunit, which are noncovalently bound. Collagen binding is primarily provided by integrins α1β1, α2β1, α10β1 and α11β1. Integrin α1β1 binds to collagen via the MIDAS motif in the α subunit I domain. It preferentially binds collagens IV, VI and type XIII collagen, but also fibril-forming collagens. Specific binding sites in collagen I and IV have been identified. This receptor is situated mainly on mesenchymal cells. Functions include: fibroblast proliferation; regulation of collagen synthesis and MMP expression; response to renal injury. Integrin α2β1 preferentially binds fibril-forming collagens. Specific binding sites in collagen I and III have been identified. Integrin α2β1 is expressed mainly on epithelial cells and platelets. Functions include: platelet adhesion - the most abundant receptor for collagen in platelets; branching morphogenesis; mast cell activation; keratinocyte adhesion and it is the main regulator of cell migration. Integrin α10β1 preferentially binds collagens IV and VI, but also collagen II. It is expressed on chondrocytes and cardiac muscle. Involved in growth plate morphogenesis and function. Integrin α11β1 is expressed by mesenchymal cells in some parts of embryo during its development and also in muscles in adults: it preferably binds fibrillar collagen. Integrin receptors capable of collagen binding could, according to results of (Garnotel R et al.
=== Purification === High thorium concentrations are needed in nuclear applications. In particular, concentrations of atoms with high neutron capture cross-sections must be very low (for example, gadolinium concentrations must be lower than one part per million by weight). Previously, repeated dissolution and recrystallisation was used to achieve high purity. Today, liquid solvent extraction procedures involving selective complexation of Th4+ are used. For example, following alkaline digestion and the removal of phosphate, the resulting nitrato complexes of thorium, uranium, and the rare earths can be separated by extraction with tributyl phosphate in kerosene.
Sources: en.wikipedia.org
Agnolín, Bogan & Lucero (2026) consider Balaena pampaea, Notiocetus romerianus and N. platensis to be nomina dubia, interpreting the fossil material of N. platensis as remains of an indeterminate baleen whale, and interpreting fossils of B. pampaea and N. romerianus as remains of an indeterminate balaenid. Lambert et al. (2026) report shark feeding traces on bones of cetacean specimens from the Pliocene Kattendijk Formation (Belgium), including evidence of a bluntnose sixgill shark feeding on a right whale Balaenella brachyrhynus and evidence of Carcharodon plicatilis feeding on a member of the genus Casatia. López-Galán, Ferrón & Botella (2026) study ecomorphological variation of extant and extinct filter-feeding cetaceans, pachycormiform fishes and selachians, interpreting members of the three groups as repeatedly converging toward analogous functional designs, but also interpreting their convergent evolution as influenced by lineage-specific constraints.
== Career == Clausen was elected as a member of the Legislative Assembly for the Stanley constituency in the 2005 election. She was elected as a member of the Legislative Council, which was reconstituted into the Legislative Assembly with the implementation of the 2009 Constitution. Clausen was elected to the Legislative Council at the 2005 general election, but lost her seat four years later in the 2009 general election. In October 2019, Clausen became the Director of Natural Resources for the Falkland Islands Government. This role had a wide-ranging remit, from supporting the economic growth of the Islands to helping ensure the sustainability of fisheries, farming and natural environment. In 2024, it was announced that she had been appointed to succeed Andy Keeling as Chief Executive of the Falkland Islands Government. She is the first resident of the Falkland Islands and first woman to hold the position.
Platelets also promote angiogenesis and tissue regeneration to maintain overall vascular integrity by releasing growth factors like vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF). Their multifunctional role displays the challenge of innovating synthetic platelets capable of effectively replicating their physiological functions.
==== Parkinson's disease ==== Parkinson's disease may be due to mitochondrial dysfunction or oxidative stress, both of which could be caused by a decrease in glutathione levels. Administration of N-acetylcysteine has been shown to counter age-related damage to mitochondria. The therapeutic effects of N-acetylcysteine in the treatment of Parkinson's disease has not been examined yet, though there is a clinical trial that is currently ongoing.
The Indian Army during British rule, also referred to as the British Indian Army, was the main military force of India until national independence in 1947. Formed in 1895 by uniting the three Presidency armies, it was responsible for the defence of both the British Raj and the princely states, which could also have their own armies. As stated in The Imperial Gazetteer of India, the "British Government has undertaken to protect the dominions of the Native princes from invasion and even from rebellion within: its army is organized for the defence not merely of British India, but of all possessions under the suzerainty of the King-Emperor." The Indian Army was a vital part of the British Empire's military forces, especially in World War I and World War II. The Indian Presidency armies were originally under East India Company command, and comprised the Bengal Army, Madras Army, and Bombay Army. After the Indian Rebellion of 1857, all company troops were transferred to the British Crown. In 1879, the Presidency armies were integrated into a system of four Commands with a central Commander-in-Chief. On 1 April 1895, the Presidency armies were dissolved and unified into a single Indian Army, also divided into four Commands, and the term "Indian Army" was officially used by 1903. The Commands were later replaced by two "Armies" in 1908—the Northern and Southern Army—but the Command system was restored in 1920. About 1.5 million Indian soldiers served during the First World War.
Sources: en.wikipedia.org
The other non-enzymatic reaction is the Maillard reaction, also responsible for developing flavors in food during the cooking process. Examples of foods that undergo Maillard reaction include breads, steaks, and potatoes. It is a chemical reaction that takes place between the amine group of a free amino acid and the carbonyl group of a reducing sugar, usually with the addition of heat. The sugar interacts with the amino acid, producing a variety of odors and flavors. The Maillard reaction is the basis for producing artificial flavors for processed foods in the flavoring industry since the type of amino acid involved determines the resulting flavor. Melanoidins are brown, high molecular weight heterogeneous polymers that are formed when sugars and amino acids combine through the Maillard reaction at high temperatures and low water activity. Melanoidins are commonly present in foods that have undergone some form of non-enzymatic browning, such as barley malts (Vienna and Munich), bread crust, bakery products and coffee. They are also present in the wastewater of sugar refineries, necessitating treatment in order to avoid contamination around the outflow of these refineries.
=== 1970s to 2011 === Though e-commerce on the dark web started around 2006, illicit goods were among the first items to be transacted using the internet, when in the early 1970s students at Stanford University and Massachusetts Institute of Technology used the ARPANET to coordinate the purchase of cannabis. By the end of the 1980s, newsgroups like alt.drugs would become online centres of drug discussion and information; however, any related deals were arranged entirely off-site directly between individuals. With the development and popularization of the World Wide Web and e-commerce in the 1990s, the tools to discuss or conduct illicit transactions became more widely available. One of the better-known web-based drug forums, The Hive, launched in 1997, serving as an information sharing forum for practical drug synthesis and legal discussion. The Hive was featured in a Dateline NBC special called The "X" Files in 2001, bringing the subject into public discourse. From 2003, the "Research Chemical Mailing List" (RCML) would discuss sourcing "Research Chemicals" from legal and grey sources as an alternative to forums such as alt.drugs.psychedelics. However Operation Web Tryp led to a series of website shut downs and arrests in this area. Since the year 2000, some of the emerging cyber-arms industry operates online, including the Eastern European "Cyber-arms Bazaar", trafficking in the most powerful crimeware and hacking tools. In the 2000s, early cybercrime and carding forums such as ShadowCrew experimented with drug wholesaling on a limited scale.
== Desorption mass spectrometry matrix == In mass spectrometry this compound is often abbreviated as "3-NBA" or "m-NBA." It has been used as a liquid matrix for fast atom bombardment and matrix-assisted laser desorption ionization. In electrospray ionization 3-NBA is doped into low surface tension spray solvents to increase analyte charging.
On December 13, 2018, the teaser of the film Black Antenna featuring the song "Rainier Fog" was released on Alice in Chains' official YouTube channel, with drummer Sean Kinney stating; "We've always toyed with the idea of creating videos for every song on one of our albums. Not only did we do that for Rainier Fog, it got totally out of hand and we made a whole goddamn movie. Everything that will be seen in the videos will be footage from Black Antenna to preface the complete film's release." "Rainier Fog" was released as a single on February 26, 2019. The official trailer for Black Antenna was released on Alice in Chains' YouTube Channel on February 28, 2019. Besides a 90-minute film, a 10-part web-series focused on each track from the album was planned. Episodes 1 and 2, "The One You Know" and "Rainier Fog", respectively, were released on March 7, 2019. The tenth and last episode, "All I Am", was released on July 17, 2019. The official music video for "Rainier Fog" was released on YouTube on May 15, 2019, and was co-directed by Alice in Chains and Peter Darley Miller, who also directed the band's 2013 mockumentary, AIC 23. On December 1, 2020, Alice in Chains was honored with the Founders Award from Seattle's Museum of Pop Culture. The benefit concert featured tribute performances from artists such as Ann Wilson, Korn, Metallica, Fishbone, Dallas Green, Billy Corgan, Tad Doyle, members of Soundgarden and Pearl Jam, among others. The event was made available for streaming for free and raised more than $600,000 for the museum in its first night.
Murillo, Mario; Jesus Rey Avirama (September 1, 2003). Colombia and the United States: War, Terrorism and Destabilization. Seven Stories Press. ISBN 1-58322-606-0. Palacios, Marco (1995). Entre la legitimidad y la violencia: Colombia 1875–1994 (in Spanish). Norma. Pardo Rueda, Rafael (2004). La historia de las guerras (in Spanish). Ediciones B-Vergara. ISBN 958-97405-5-3. Hennecke, Angelika (2006). Zwischen Faszination und Gewalt : Kolumbien—unser gemeinsamer Nenner: Reflexionen über das Verhältnis zwischen kultureller Identität, Kommunikation und Medien anhand der diskursanalytischen Untersuchung einer kolumbianischen Werbekampagne (in German). Frankfurt am Main: Peter Lang. ISBN 3-631-54930-X. Pizarro Leongómez, Eduardo (1991). Las Farc: de la autodefensa a la combinación de todas las formas de lucha. Universidad Nacional. Tirado Mejía, Alvaro, ed. (1989). Nueva historia de Colombia. Planeta. Journals and periodicals
Sources: en.wikipedia.org
It is registered as a pharmaceutical product in Russia, where it is typically supplied as a nasal solution. In most other countries it is not an approved drug and is traded as a research chemical instead. Approval status depends entirely on the jurisdiction involved.
Most published work uses intranasal administration, matching the route of the registered Russian formulation. Some animal experiments use intravenous or intraperitoneal injection. The route matters because the intact peptide is cleared rapidly from blood, so exposure differs between methods.
A purity value describes the share of the powder accounted for by the target peptide, usually by high-performance liquid chromatography. It does not confirm that the sequence is correct, which requires mass spectrometry or amino acid analysis. Purity and identity are separate checks.
Each freeze-thaw cycle can degrade a fraction of the peptide and promote aggregation. Dividing a stock solution into single-use volumes removes repeated cycling as a variable. It also limits the time a thawed solution spends at room temperature.