This is a working overview of Mass spectrometry, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-09-15 and is reviewed periodically as new material appears.
Handling practice centers on limiting moisture, heat, and mechanical stress. Powder is typically allowed to reach room temperature before opening so that condensation does not form on the contents, and solutions are prepared with sterile or low-particulate water. Peptides can adsorb to certain plastics and membrane filters, so container and filter material is sometimes specified to reduce losses at low concentrations. Working aliquots are usually frozen separately rather than sampled repeatedly from one stock. Recording lot number, preparation date, and storage conditions supports later comparison between experiments.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, which separates the target peptide from truncated sequences and other synthesis by-products. Mass spectrometry, typically electrospray ionization coupled to liquid chromatography, confirms the expected mass and helps detect modifications. Amino acid analysis can verify composition when residue-level confirmation is needed. Because common impurities differ from the target by only one or two residues, chromatographic resolution often matters more than a single headline purity percentage. Impurity profiles are most informative when compared against a validated reference standard.
Lyophilized material is generally reported as stable for extended periods when kept cold, dry, and protected from light. In solution, the main degradation routes for a peptide of this type are hydrolysis of peptide bonds and aggregation. The sequence contains no cysteine, so disulfide-driven oxidation is not a primary concern, though methionine and tryptophan are also absent. Stability depends on pH, buffer composition, and concentration, with acidic conditions often reported as more favorable than neutral or alkaline ones. Repeated freeze-thaw cycles can promote aggregation, and how fast degradation proceeds at room temperature in specific formulations remains an open question.
The peptide was first described in the early 1990s by a group studying gastric secretions and tissue repair. Its fifteen-residue chain is usually written as GEPPPGKPADDAGLV in single-letter code. The free peptide has the formula C62H98N16O22 and a theoretical mass near 1419.5 daltons. These identifiers are established chemical facts that can be checked against standard peptide databases. There is no ambiguity about the primary structure.
Most published findings come from rodent experiments using induced injury or surgical models. Human reports remain scarce and are largely observational, which limits how much can be stated with confidence. Questions about absorption, distribution, metabolism, and clearance in people are still open. Dose translation between species is likewise unresolved. Researchers tend to read the animal literature as a starting point rather than a settled account.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Typical lyophilized form |
| Solubility | Freely soluble in water | Also dissolves in common polar solvents |
| Storage temperature | Minus 20 degrees Celsius or lower | Applies to dry powder, desiccated and dark |
| Typical analytical methods | Reversed-phase HPLC and mass spectrometry | Used together for purity and identity |
| Primary degradation route | Hydrolysis and aggregation | No cysteine present, so disulfide formation is unlikely |
Interest in the peptide has grown through online communities that discuss self-administered use, which sits outside formal research settings. Regulatory status varies by country, and in many jurisdictions the compound is not approved as a therapeutic product. Questions about optimal routes of administration, long-term effects, and dose-response relationships remain open. Published pharmacokinetic data in humans are limited, and much of what circulates in popular discussion is extrapolated from animal work rather than measured directly in people.
BPC-157 is a synthetic peptide built from fifteen amino acids, referred to in the literature as a pentadecapeptide. Its sequence was derived from a larger protein found in human gastric juice, commonly called body protection compound. Researchers first described the fragment in the early 1990s and named it after the parent protein plus a numeric identifier. The peptide does not correspond to a single marketed medicine; it is primarily a laboratory research material. Suppliers distribute it as a lyophilized powder intended for experimental use.
Outside laboratory supply channels, the peptide is sold as a research chemical, a category that carries no requirement to demonstrate purity, identity, or freedom from contamination. Because it is not an approved medicine, products labeled BPC-157 sit in a regulatory gap in many countries, and actual content may differ from the label. Sports organizations list it among prohibited substances, so its presence in an athlete's sample can produce a doping finding regardless of how the material was obtained.
BPC-157 is a synthetic peptide of fifteen amino acids, written as GEPPPGKPADDAGLV, whose sequence matches part of a larger protein identified in human gastric juice. That parent protein was described in stomach-secretion research, and the fifteen-residue fragment was named body protection compound, which gives the peptide its common label. Material used in experiments is produced by solid-phase peptide synthesis rather than extracted from tissue. The reported molecular weight is about 1419 daltons, and the chain contains several proline residues, a feature that appears in discussions of its resistance to enzymatic breakdown.
== Pharmacology == Experiments on former addicts indicated it was quite addictive and in high doses, compared to other opioids, may have increased abuse potential in former and current opioid addicts. While some effort was first suggested for drafting of a resolution urging governments to stop manufacture and use of ketobemidone, this result was not in agreement with clinical observations, and another study in 1958 did not find it more addictive than morphine. That study noticed that while for morphine the dose for euphoria is the same as that for analgesia, for ketobemidone the analgesic dose was well below the euphoric dose. Thus, even compared to morphine, ketobemidone may be much more effective without causing significant euphoria and thus having a lower risk of addiction under the supervision of a qualified clinician. Ketobemidone is mostly used in the Scandinavian countries, with Denmark topping the statistics. Analgesia after 5-10 mg orally or 5–7.5 mg intravenously lasts 3–5 hours. Ketobemidone is also available in preparations with a spasmolytic, which can improve the analgesia.
The isotope 231Pa can be prepared by irradiating 230Th with slow neutrons, converting it to the beta-decaying 231Th; or, by irradiating 232Th with fast neutrons, generating (as one product) 231Th and 2 neutrons. Protactinium metal has been prepared by reduction of its fluoride with calcium, lithium, or barium at a temperature of 1300–1400 °C.
Certain serotonergic psychedelics and related non-hallucinogenic drugs, acting as serotonin 5-HT2A receptor agonists, have been reported to have mild stimulant and/or "psychic energizing" (i.e., acute antidepressant) effects, both in animals and humans. These effects are often present at low or sub-hallucinogenic doses. Psychedelics are also known to promote wakefulness or cause insomnia. Psychedelic and related drugs that have been reported to produce stimulant effects include the phenethylamines 2,5-DMA (DOH), DOM, DOET, DOPR, DON, MTFEM, Ariadne (4C-DOM; BL-3912; Dimoxamine), 2C-B, 2C-D, 2C-G-N, and ASR-2001 (2CB-5PrO), and the tryptamines 5-MeO-DiPT and 5-MeO-MiPT, among others. The lysergamide LSD has also been reported to have mild stimulant effects. Conversely, psilocybin does not seem to produce the same stimulant effects. The non-hallucinogenic Ariadne was under development as a potential pharmaceutical drug to take advantage of such effects in the treatment of conditions like depression in the 1970s, and reached phase 3 clinical trials for such indications, but was shelved reportedly for strategic economic reasons. ASR-2001, which is likewise non-hallucinogenic, is under development for use as a stimulant-like medication for treatment of psychiatric disorders. Serotonin 5-HT2A receptor agonists have been found to increase dopamine levels in brain areas like the frontal cortex, striatum, and nucleus accumbens in animal studies.
Gerry Gable (born 27 January 1937); political activist; was editor of Searchlight magazine; was member of Communist Party of Great Britain; worked as runner on Communist Party's Daily Worker newspaper; left the Communist Party because of their anti-Israel policy and because "first and foremost [he has] always been a Jewish trade unionist"; was commissioned by BBC to produce research for a BBC Panorama programme "Maggie's Militant Tendency"; was convicted in January 1964 of burglary of historian David Irving's flat Martha Gellhorn (8 November 1908 – 15 February 1998) American novelist, travel writer, and journalist who settled, retired and died in England; considered one of the great war correspondents of the 20th century. Andrew Gold (journalist) (b.1989); British Jewish journalist, YouTuber, filmmaker, author, podcaster;in 2023, Gold launched his YouTube podcast, Heretics; has written for UnHerd, Vice, Jewish News, HuffPost , Times of Israel and the BBC. Tanya Gold (born 31 December 1973) is an English journalist who has written for The Jewish Chronicle, The New York Times The Guardian, the Daily Mail, The Independent, The Daily Telegraph, The Sunday Times and the Evening Standard, and for The Spectator magazine. Vivien Goldman is a British punk rock and reggae journalist and historian, writer and musician of German Jewish ancestry.
Sources: en.wikipedia.org
== History == In 1978, a dying friend and colleague presented the late University of Chicago pharmacologist Leon Goldberg with a clinical challenge. Struggling with the pain of prostatic cancer that had metastasized to his bones, the man was now declining the morphine he required for analgesia because of constipation. Research on opioids which would target only the sub-types of receptors associated with pain relief and not with side effects had seen little success outside of in-vitro models. Considering drugs such as loperamide, which acted on the opioid receptors in the gut without acting on the central nervous system, Goldberg proposed a targeted opioid receptor antagonist. Thousands of opioid-like molecules had been synthesized by pharmaceutical companies looking for the better analgesic - and many of those with no pain-relieving properties had been shelved. Screening these compounds led to the examination of putative antagonists which when modified had properties that suggested they might not readily cross the blood–brain barrier based on their size and charge. One of these compounds, N-methyl-naltrexone (MNTX), was amongst a group of compounds synthesized by Boehringer Ingelheim. The compound looked promising and passed initial screening in which rodents were given opioids along with charcoal meals to track GI transit, and were tested for analgesia. In a 1982 paper by Russell et al., it was first reported that the GI effects of the opioids could be prevented without affecting centrally mediated analgesia in this model.
In men, blockade of the AR by bicalutamide in the pituitary gland and hypothalamus prevents the negative feedback of androgens on the hypothalamic–pituitary–gonadal (HPG) axis, resulting in an increase in luteinizing hormone (LH) secretion and levels. Follicle-stimulating hormone (FSH) levels, in contrast, remain essentially unchanged. The increase in LH levels leads to an elevation in androgen and estrogen levels. At a dosage of 150 mg/day, bicalutamide has been found to increase testosterone levels by about 1.5- to 2-fold (59–97% increase) and estradiol levels by about 1.5- to 2.5-fold (65–146% increase). However, there is variability in these increases, and in one clinical trial, the highest testosterone concentration that occurred with 50 mg/day bicalutamide monotherapy was 2,306 ng/dL, which was five times the normal average level of testosterone in men. Levels of DHT are also increased to a lesser extent (by 24–30%), and concentrations of sex hormone-binding globulin (SHBG) and prolactin increase as well (by 8–42% and 40–65%, respectively) secondary to the increase in estradiol levels. The estradiol concentrations produced in men by bicalutamide monotherapy are said to approximate the low-normal estradiol levels of a premenopausal woman, while testosterone levels generally remain in the high end of the normal male range and rarely exceed it.
== Theoretical background == The acid dissociation constant for an acid is a direct consequence of the underlying thermodynamics of the dissociation reaction; the pKa value is directly proportional to the standard Gibbs free energy change for the reaction. The value of the pKa changes with temperature and can be understood qualitatively based on Le Chatelier's principle: when the reaction is endothermic, Ka increases and pKa decreases with increasing temperature; the opposite is true for exothermic reactions. The value of pKa also depends on molecular structure of the acid in many ways. For example, Linus Pauling proposed two rules: one for successive pKa of polyprotic acids (see Polyprotic acids below), and one to estimate the pKa of oxyacids based on the number of =O and −OH groups (see Factors that affect pKa values below). Other structural factors that influence the magnitude of the acid dissociation constant include inductive effects, mesomeric effects, and hydrogen bonding. Hammett type equations have frequently been applied to the estimation of pKa. The quantitative behaviour of acids and bases in solution can be understood only if their pKa values are known. In particular, the pH of a solution can be predicted when the analytical concentration and pKa values of all acids and bases are known; conversely, it is possible to calculate the equilibrium concentration of the acids and bases in solution when the pH is known. These calculations find application in many different areas of chemistry, biology, medicine, and geology.
== Structure == At the center of every tooth is a hollow area that houses soft tissues, such as the nerve, blood vessels, and connective tissue. This hollow area contains a relatively wide space in the coronal portion of the tooth called the pulp chamber. These canals run through the center of the roots, similar to the way graphite runs through a pencil. The pulp receives nutrition through the blood vessels, and sensory nerves carry signals back to the brain. In the case of irreversible damage to the pulp, root canal treatment can relieve associated dental pain. Root canal anatomy consists of the pulp chamber and root canals. Both contain the dental pulp. The smaller branches, referred to as accessory canals, are most frequently found near the root end (apex), but may be encountered anywhere along the root length. The total number of root canals per tooth depends on the number of the tooth roots ranging from one to four, five or more in some cases. Sometimes there are more than one root canal per root. Some teeth have a more variable internal anatomy than others. An unusual root canal shape, complex branching (especially the existence of horizontal branches), and multiple root canals are considered as the main causes of root canal treatment failures. (For example, if a secondary root canal goes unnoticed by the dentist and is not cleaned and sealed, it will remain infected, causing the root canal therapy to fail.)
On Czapek Yeast Extract Agar medium at 25 °C, white colonies grow in a plane, attaining a velvety to deeply floccose texture, with colony sizes that are 33–35 mm in diameter. On this medium, olive conidia are produced. The reverse of the plate can be pale or slightly tinted brown. On Malt Extract Agar medium at 25 °C, growth is rare, yet rapid when occurring, forming a velvety surface. At first, colonies are yellow-green, but ultimately turn olive due to conidial production. Colony diameter can range in size from 35 mm to 70 mm. The reverse of the plate is similar to that observed for Czapek Yeast Extract Agar medium. On 25% Glycerol Nitrate Agar at 25 °C, colony growth is planar, yet develops into a thick gel, with colony size diameter ranging from 6–12 mm. The back of the plate is described as pale or olive. At 5 °C, 25% Glycerol Nitrate Agar supports germination and a colonial growth of up to 3 mm in diameter. This species fails to grow at 37 °C. On Creatine Sucrose Agar at 25 °C, colony size diameter ranges from 4 to 10 mm. Growth is restricted, and medium pH remains around 7. No change on the back of the plate is noted. Growth on media containing orange fruit pieces for seven days at room temperature results in fruit decay, accompanied by a characteristic odour. After 14 days at room temperature, the reverse is colourless to light brown.
Sources: en.wikipedia.org
At midnight between 17 and 18 April 1980, the country was granted independence by Britain under the name of Zimbabwe. A new national flag was adopted, the draft for which had been handed to the Minister of Public Works Richard Hove by an unspecified designer. The initial design did not include the Zimbabwe Bird, which was added at the suggestion of Cederic Herbert, who pointed out its uniqueness and history. The final draft went through the approval of the Prime Minister-elect Robert Mugabe. The adoption of the new flag coincided with the swearing-in of Canaan Banana as the country's new president. The Zimbabwe Bird, used on every flag since 1968, is based on a statue discovered from the medieval ruined city of Great Zimbabwe in the country's south-east.
Beginning in about 3000 BC, arsenic was mined and added to copper in the alloying of bronze, but the adverse health effects of working with arsenic led to it being abandoned when a viable alternative, tin, was discovered. During the Elizabethan era, some women used toxic makeup composed of vinegar, chalk, and arsenic applied topically to whiten their skin. This use of arsenic was intended to prevent aging and creasing of the skin, but some arsenic was inevitably absorbed into the bloodstream. During the Victorian era (late 19th century) in the United States, U.S. newspapers advertised "arsenic complexion wafers" that promised to remove facial blemishes such as moles and pimples. Some pigments, most notably the popular Emerald Green (known also under several other names), were based on arsenic compounds. Overexposure to these pigments was a frequent cause of accidental poisoning of artists and craftsmen. Arsenic became a favored method for murder of the Middle Ages and Renaissance, particularly among the ruling classes in Italy, allegedly. Because the symptoms are similar to those of cholera, which was common at the time, arsenic poisoning often went undetected. By the 19th century, it had acquired the nickname "inheritance powder", perhaps because impatient heirs were known or suspected to use it to ensure or accelerate their inheritances. It was also a common murder technique in the 19th century in domestic violence situations, such as the case of Rebecca Copin, who attempted to poison her husband by "putting arsenic in his coffee".
Eastern countries such as China and Russia and most Muslim nations like Iran, Indonesia and Pakistan remained staunchly opposed." The outcome document recommended treatment, prevention and other public health measures, and committed to "intensifying our efforts to prevent and counter" drug production and trafficking, through, "inter alia, more effective drug-related crime prevention and law enforcement measures." A statement signed by 189 civil society organizations criticized the 2016 outcome document, itemizing the lack of progress and calling out the "highly problematic, non-inclusive and non-transparent" process that made it possible for "a handful of vocal and regressive countries [to] block progressive language", resulting in "an expensive restatement of previous agreements and conventions".
=== Chemical and molecular properties === A neutral atom has the same number of electrons as protons. Thus different isotopes of a given element all have the same number of electrons and share a similar electronic structure. Because the chemical behaviour of an atom is largely determined by its electronic structure, different isotopes exhibit nearly identical chemical behaviour. The main exception to this is the kinetic isotope effect: due to their larger masses, heavier isotopes tend to react somewhat more slowly than lighter isotopes of the same element. This is most pronounced by far for protium (1H), deuterium (2H), and tritium (3H), because deuterium has twice the mass of protium and tritium has three times the mass of protium. These mass differences also affect the behavior of their respective chemical bonds, by changing the center of gravity (reduced mass) of the atomic systems. However, for heavier elements, the relative mass difference between isotopes is much less so that the mass-difference effects on chemistry are usually negligible. (Heavy elements also have relatively more neutrons than lighter elements, so the ratio of the nuclear mass to the collective electronic mass is slightly greater.) There is also an equilibrium isotope effect.
=== Brands === In 2017, loratadine was available under many brand names and in many forms worldwide, including several combination drug formulations with pseudoephedrine, paracetamol, betamethasone, ambroxol, salbutamol, phenylephrine, and dexamethasone.
Sources: en.wikipedia.org
Reversed-phase liquid chromatography with ultraviolet detection gives a purity estimate, while mass spectrometry confirms molecular mass and flags modifications. Amino acid analysis can add compositional confirmation. Results are most meaningful when a validated reference standard is run alongside the sample.
Cold, dry, and dark conditions are standard, typically at or below minus twenty degrees Celsius for long-term holding. Vials are usually warmed to room temperature before opening to prevent condensation. Repeated warming and cooling of the same vial is generally avoided.
This depends on pH, buffer, and concentration, with acidic conditions often reported as more favorable. Hydrolysis accelerates at room temperature, so solutions are commonly prepared fresh or stored frozen in single-use aliquots. No single shelf life applies across formulations.
The peptide is synthetic, but its sequence matches a segment of a protein present in human gastric juice. It does not occur as a free fifteen-residue peptide in the body.