Sarin(NATOdesignationGB[short forG-series,"B" ]) is an extremely toxicorganophosphorus compound.[4]A colourless, odourlessliquid,it is used as achemical weapondue to its extreme potency as anerve agent.Exposure can be lethal even at very low concentrations, where death can occur within one to ten minutes after direct inhalation of a lethal dose,[5][6]due to suffocation from respiratory paralysis, unless antidotes are quickly administered.[4]People who absorb a non-lethal dose and do not receive immediate medical treatment may suffer permanent neurological damage.[citation needed]

Sarin[1]
S-Sarin
Names
Pronunciation /ˈsɑːrɪn/
Preferred IUPAC name
Propan-2-yl methylphosphonofluoridate
Other names
(RS)-O-Isopropyl methylphosphonofluoridate; IMPF;
GB;[2]
2-(Fluoro-methylphosphoryl)oxypropane;
Phosphonofluoridic acid,P-methyl-, 1-methylethyl ester
EA-1208
TL-1618
T-144
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
UNII
  • InChI=1S/C4H10FO2P/c1-4(2)7-8(3,5)6/h4H,1-3H3checkY
    Key: DYAHQFWOVKZOOW-UHFFFAOYSA-NcheckY
  • InChI=1/C4H10FO2P/c1-4(2)7-8(3,5)6/h4H,1-3H3
  • InChI=1/C4H10FO2P/c1-4(2)7-8(3,5)6/h4H,1-3H3
    Key: DYAHQFWOVKZOOW-UHFFFAOYAY
  • FP(=O)(OC(C)C)C
Properties
C4H10FO2P
Molar mass 140.094g·mol−1
Appearance Clear colourless liquid, brownish if impure
Odor Odourless in pure form. Impure sarin can smell like mustard or burned rubber.
Density 1.0887 g/cm3(25 °C)
1.102 g/cm3(20 °C)
Melting point −56 °C (−69 °F; 217 K)
Boiling point 158 °C (316 °F; 431 K)
Miscible
logP 0.30
Hazards
Occupational safety and health(OHS/OSH):
Main hazards
Extremely lethalcholinergicagent.
GHSlabelling:
GHS06: Toxic
NFPA 704(fire diamond)
NFPA 704 four-colored diamondHealth 4: Very short exposure could cause death or major residual injury. E.g. VX gasFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g. calciumSpecial hazards (white): no code
4
1
1
0.00003 mg/m3(TWA), 0.0001 mg/m3(STEL)
Lethal doseor concentration (LD, LC):
39 μg/kg (intravenous, rat)[3]
NIOSH(US health exposure limits):
IDLH(Immediate danger)
0.1 mg/m3
Safety data sheet(SDS) Lethal Nerve Agent Sarin (GB)
Except where otherwise noted, data are given for materials in theirstandard state(at 25 °C [77 °F], 100 kPa).

Sarin is widely considered aweapon of mass destruction.Production and stockpiling of sarin was outlawed as of April 1997 by theChemical Weapons Conventionof 1993, and it is classified as aSchedule 1 substance.

Health effects

edit
Biological effects of sarin in the neuromuscular junction. Sarin (red), acetylcholinesterase (yellow), acetylcholine (blue)[clarification needed]

Like some other nerve agents that affect theneurotransmitteracetylcholine,sarin attacks thenervous systemby interfering with the degradation of the neurotransmitter acetylcholine atneuromuscular junctions.Death usually occurs as a result ofasphyxiadue to the inability to control the muscles involved in breathing.[7]

Initial symptoms following exposure to sarin are arunny nose,tightness in the chest, andconstriction of the pupils.Soon after, the person will have difficulty breathing and experiencenauseaand drooling. This progresses to losing control of bodily functions, which may cause the person to vomit, defecate, and urinate. This phase is followed bytwitchingand jerking. Ultimately, the person becomes comatose and suffocates in a series of convulsivespasms.Common mnemonics for the symptomatology of organophosphate poisoning, including sarin, are the "killer Bs" ofbronchorrheaandbronchospasmbecause they are the leading cause of death,[8]andSLUDGE– salivation,lacrimation,urination, defecation, gastrointestinal distress, and emesis (vomiting). Death may follow in one to ten minutes after direct inhalation, but may also occur after a delay ranging from hours to several weeks, in cases where exposure is limited but no antidote is applied.[7]

Sarin has a highvolatility(ease with which a liquid can turn into vapour) relative to similar nerve agents, making inhalation very easy, and may even absorb through the skin. A person's clothing can release sarin for about 30 minutes after it has come in contact with sarin gas, which can lead to exposure of other people.[9]

Management

edit

Treatment measures have been described.[9]Treatment is typically with theantidotesatropineandpralidoxime.[4]Atropine, anantagonisttomuscarinic acetylcholine receptors,is given to treat the physiological symptoms of poisoning. Since muscular response to acetylcholine is mediated throughnicotinic acetylcholine receptors,atropine does not counteract the muscular symptoms. Pralidoxime can regeneratecholinesterasesif administered within approximately five hours.Biperiden,a syntheticacetylcholine antagonist,has been suggested as an alternative to atropine due to its betterblood–brain barrierpenetration and higher efficacy.[10]

Mechanism of action

edit

Sarin is a potentinhibitor of acetylcholinesterase,[11]an enzyme that degrades theneurotransmitteracetylcholineafter it is released into thesynaptic cleft.In vertebrates, acetylcholine is the neurotransmitter used at the neuromuscular junction, where signals are transmitted betweenneuronsfrom thecentral nervous systemto muscle fibres. Normally, acetylcholine is released from the neuron to stimulate the muscle, after which it is degraded byacetylcholinesterase,allowing the muscle to relax. A build-up of acetylcholine in thesynaptic cleft,due to the inhibition of acetylcholinesterase, means the neurotransmitter continues to act on the muscle fibre, so that any nerve impulses are effectively continually transmitted.

Sarin acts on acetylcholinesterase by forming acovalent bondwith the particularserineresidue at the active site. Fluoride is theleaving group,and the resulting organo-phosphoester is robust andbiologically inactive.[12][13]

Its mechanism of action resembles that of some commonly usedinsecticides,such asmalathion.In terms of biological activity, it resemblescarbamateinsecticides, such asSevin,and the medicinespyridostigmine,neostigmine,andphysostigmine.

Diagnostic tests

edit

Controlled studies in healthy men have shown that a nontoxic 0.43 mg oral dose administered in several portions over a 3-day interval caused average maximum depressions of 22 and 30%, respectively, in plasma and erythrocyte acetylcholinesterase levels. A single acute 0.5 mg dose caused mild symptoms of intoxication and an average reduction of 38% in both measures of acetylcholinesterase activity. Sarin in blood is rapidly degraded eitherin vivoorin vitro.Its primary inactivemetaboliteshavein vivoserum half-lives of approximately 24 hours. The serum level of unbound isopropyl methylphosphonic acid (IMPA), a sarinhydrolysisproduct, ranged from 2–135 μg/L in survivors of a terrorist attack during the first four hours post-exposure. Sarin or its metabolites may be determined in blood or urine by gas or liquidchromatography,while acetylcholinesterase activity is usually measured by enzymatic methods.[14]

A newer method called "fluoride regeneration" or "fluoride reactivation" detects the presence of nerve agents for a longer period after exposure than the methods described above. Fluoride reactivation is a technique that has been explored since at least the early 2000s. This technique obviates some of the deficiencies of older procedures. Sarin not only reacts with the water in the blood plasma through hydrolysis (forming so-called 'free metabolites'), but also reacts with various proteins to form 'protein adducts'. These protein adducts are not so easily removed from the body, and remain for a longer period of time than the free metabolites. One clear advantage of this process is that the period, post-exposure, for determination of sarin exposure is much longer, possibly five to eight weeks according to at least one study.[15][16]

Toxicity

edit

As a nerve gas, sarin in its purest form is estimated to be 26 times more deadly thancyanide.[17]TheLD50ofsubcutaneously injectedsarin in mice is 172 μg/kg.[18]

Sarin is highly toxic, whether by contact with the skin or breathed in. The toxicity of sarin in humans is largely based on calculations from studies with animals. The lethal concentration of sarin in air is approximately 28–35 mg per cubic meter per minute for a two-minute exposure time by a healthy adult breathing normally (exchanging 15 liters of air per minute, lower 28 mg/m3value is for general population).[19]This number represents the estimated lethal concentration for 50% of exposed victims, theLCt50value. TheLCt95orLCt100value is estimated to be 40–83 mg per cubic meter for exposure time of two minutes.[20][21]Calculating effects for different exposure times and concentrations requires following specific toxic load models. In general, brief exposures to higher concentrations are more lethal than comparable long time exposures to low concentrations.[22]There are many ways to make relative comparisons between toxic substances. The list below compares sarin to some current and historic chemical warfare agents, with a direct comparison to the respiratory LCt50:

Production and structure

edit

Sarin is achiralmolecule because it has four chemically distinctsubstituentsattached to thetetrahedralphosphorus center.[25]TheSPform (the(–) optical isomer) is the more activeenantiomerdue to its greaterbinding affinitytoacetylcholinesterase.[26][27]The P-F bond is easily broken bynucleophilicagents, such as water and hydroxide. At highpH,sarin decomposes rapidly to nontoxicphosphonic acidderivatives.[28]

It is almost always manufactured as aracemic mixture(a 1:1 mixture of its enantiomeric forms) as this involves a much simplersynthesiswhile providing an adequate weapon.[26][27]

A number of production pathways can be used to create sarin. The final reaction typically involves attachment of the isopropoxy group to the phosphorus with analcoholysiswithisopropyl alcohol.Two variants of this final step are common. One is the reaction ofmethylphosphonyl difluoridewith isopropyl alcohol, which produces a racemic mixture of sarin enantiomers withhydrofluoric acidas a byproduct:[28]

The second process, known as the "Di-Di" process, uses equimolar quantities ofmethylphosphonyl difluoride(Difluoro) andmethylphosphonyl dichloride(Dichloro). This reaction gives sarin,hydrochloric acidand others minors byproducts. The Di-Di process was used by the United States for the production of its unitary sarin stockpile.[28]

The scheme below shows a generic example that employs the Di-Di method as the final esterification step; in reality, the selection of reagents and reaction conditions dictate both product structure and yield. The choice of enantiomer of the mixed chloro fluoro intermediate displayed in the diagram is arbitrary, but the final substitution is selective for chloro over fluoro as theleaving group.Inert atmosphere and anhydrous conditions (Schlenk techniques) are used for synthesis of sarin and other organophosphates.[28]

An example of "di-di" process using arbitrary reagents.

As both reactions leave considerable acid in the product, sarin produced in bulk by these methods has a short half life without further processing, and would be corrosive to containers and damaging to weapons systems. Various methods have been tried to resolve these problems. In addition to industrialrefiningtechniques to purify the chemical itself, various additives have been tried to combat the effects of the acid, such as:

Another byproduct of these two chemical processes isdiisopropyl methylphosphonate,formed when a second isopropyl alcohol reacts with the sarin itself and from disproportionation of sarin, when distilled incorrectly. The factor of its formation in esterification is that as the concentration of DF-DCl decreases, the concentration of sarin increases, the probability of DIMP formation is greater. DIMP is a natural impurity of sarin, that is almost impossible to be eliminated, mathematically, when the reaction is a 1 mol-1 mol "one-stream".[35]

This chemical degrades into isopropyl methylphosphonic acid.[36]

Degradation and shelf life

edit
Rabbit used to check for leaks at former sarin production plant (Rocky Mountain Arsenal), 1970

The most important chemical reactions of phosphoryl halides is the hydrolysis of the bond between phosphorus and the fluoride. This P-F bond is easily broken by nucleophilic agents, such as water andhydroxide.At highpH,sarin decomposes rapidly to nontoxicphosphonic acidderivatives.[37][38]The initial breakdown of sarin is into isopropyl methylphosphonic acid (IMPA), a chemical that is not commonly found in nature except as a breakdown product of sarin (this is useful for detecting the recent deployment of sarin as a weapon). IMPA then degrades intomethylphosphonic acid(MPA), which can also be produced by other organophosphates.[39]

Sarin with residual acid degrades after a period of several weeks to several months. The shelf life can be shortened by impurities inprecursor materials.According to theCIA,someIraqi sarinhad a shelf life of only a few weeks, owing mostly to impure precursors.[40]

Along with nerve agents such astabunandVX,sarin can have a short shelf life. Therefore, it is usually stored as two separate precursors that produce sarin when combined.[41]Sarin's shelf life can be extended by increasing the purity of the precursor and intermediates and incorporatingstabilizerssuch astributylamine.In some formulations, tributylamine is replaced bydiisopropylcarbodiimide(DIC), allowing sarin to be stored inaluminiumcasings. Inbinary chemical weapons,the two precursors are stored separately in the sameshelland mixed to form the agent immediately before or when the shell is in flight. This approach has the dual benefit of solving the stability issue and increasing the safety of sarin munitions.

History

edit

Sarin was discovered in 1938 inWuppertal-Elberfeld in Germany by scientists atIG Farbenwho were attempting to create stronger pesticides; it is the most toxic of the fourG-Series nerve agentsmade by Germany. The compound, which followed the discovery of thenerve agenttabun,was named in honor of its discoverers: chemistGerhardSchrader,chemistOttoAmbros,chemistGerhardRitter[de],and fromHeereswaffenamtHans-Jürgen von der Linde.[42]

Use as a weapon

edit

In mid-1939, the formula for the agent was passed to thechemical warfaresection of theGerman Army Weapons Office,which ordered that it be brought into mass production for wartime use. Pilot plants were built, and a production facility was under construction (but was not finished) by the end ofWorld War II.Estimates for total sarin production byNazi Germanyrange from 500 kg to 10 tons.[43]

Though sarin,tabun,andsomanwere incorporated intoartilleryshells, Germany did not use nerve agents againstAlliedtargets.Adolf Hitlerrefused to initiate the use of gases such as sarin as weapons.[44]

U.S.Honest John missilewarhead cutaway, showingM134Sarin bomblets (c. 1960)
Sarin gas used against animals in a weapons experiment
  • 1950s (early):NATOadopted sarin as a standard chemical weapon. The USSR and the United States produced sarin for military purposes.
  • 1953: 20-year-oldRonald Maddison,aRoyal Air Forceengineer fromConsett,County Durham,died in human testing of sarin at thePorton Downchemical warfare testing facility inWiltshire,England. Ten days after his death aninquestwas held in secret which returned a verdict ofmisadventure.In 2004, the inquest was reopened and, after a 64-day inquest hearing, the jury ruled that Maddison had been unlawfully killed by the "application of a nerve agent in a non-therapeutic experiment".[45]
  • 1957: Regular production of sarin chemical weapons ceased in the United States, though existing stocks of bulk sarin were re-distilled until 1970.[29]
  • 1976: Chile's intelligence service,DINA,assigned biochemistEugenio Berríosto develop Sarin gas within its programProyecto Andrea,to be used as a weapon against its opponents.[46]One of DINA's goals was to package it in spray cans for easy use, which, according to testimony by former DINA agentMichael Townley,was one of the planned procedures in the 1976assassination of Orlando Letelier.[46]Berríos later testified that it was used in a number of assassinations and it was planned to be used to kill inhabitants, through poisoning the water supply ofArgentinecapitalBuenos Aires,in caseOperation Soberaníatook place.[47][48]
  • March 1988:Halabja chemical attack;Over two days in March, the ethnicKurdishcity ofHalabjain northern Iraq (population 70,000) was bombarded bySaddam Hussein'sIraqi Air Forcejets with chemical bombs including sarin. An estimated 5,000 people died, almost all civilians.[49]
  • April 1988: Iraq used Sarin four times against Iranian soldiers at the end of theIran–Iraq War,helping Iraqi forces to retake control of theal-Faw Peninsuladuring theSecond Battle of al-Faw.
  • 1993: The United NationsChemical Weapons Conventionwas signed by 162 member countries, banning the production and stockpiling of many chemical weapons, including sarin. It went into effect on April 29, 1997, and called for the complete destruction of all specified stockpiles of chemical weapons by April 2007.[50]When the convention entered force, the parties declared worldwide stockpiles of 15,047 tonnes of sarin. As of November 28, 2019, 98% of the stockpiles have been destroyed.[51]
  • 1994:Matsumoto incident;the Japanese religious sectAum Shinrikyoreleased an impure form of sarin inMatsumoto, Nagano,killing eight people and harming over 500. The Australian sheep stationBanjawarnwas a testing ground.
  • 1995:Tokyo subway sarin attack;theAum Shinrikyosect released an impure form of sarin in theTokyo Metro.Twelve people died, and over 6,200 people received injuries.[52][53]
  • 2002: Pro-ChechenmilitantIbn al-Khattabmay have been assassinated with sarin by the Russian government.[54][55]
  • May 2004:Iraqi insurgentsdetonated a 155 mm shell containing binary precursors for sarin near a U.S. convoy inIraq.The shell was designed to mix the chemicals as it spun during flight. The detonated shell released only a small amount of sarin gas, either because the explosion failed to mix the binary agents properly or because the chemicals inside the shell had degraded with age. Two United States soldiers were treated after displaying the early symptoms of exposure to sarin.[56]
  • March 2013:Khan al-Assal chemical attack;Sarin was used in an attack on a town west ofAleppocity inSyria,killing 28 and wounding 124.[57]
  • August 2013:Ghouta chemical attack;Sarin was used in multiple simultaneous attacks in theGhoutaregion of theRif DimashqGovernorate of Syria during theSyrian Civil War.[58]Varying[59]sources gave a death toll of 322[60]to 1,729.[61]
  • April 2017:Khan Shaykhun chemical attack:TheSyrian Air Forcereleased sarin gas in rebel-held Idlib Province in Syria during anairstrike.[62][63]
  • April 2018: Victims of theDouma chemical attackin Syria reported to have symptoms consistent with exposure to sarin and other agents. On July 6, 2018, the Fact-Finding Mission (FFM) of the OPCW published their interim report. The report stated that, "The results show that no organophosphorous [sarin] nerve agents or their degradation products were detected in the environmental samples or in the plasma samples taken from alleged casualties". The chemical agent used in the attack was later identified as elementalchlorine.[64]
  • July 2023: The U.S. destroyed the last of its declared chemical weapons, a sarin nerve agent-filledM55 rocket,on July 7, 2023.[65]

See also

edit

References

edit
  1. ^"Material Safety Data Sheet – Lethal Nerve Agent Sarin (GB)".103d Congress, 2d Session.United States Senate. May 25, 1994.RetrievedNovember 6,2004.
  2. ^"Sarin".National Institute of Standards and Technology.RetrievedMarch 27,2011.
  3. ^"Substance Name: Sarin".ChemIDplus.U.S. National Library of Medicine, National Institutes of Health.RetrievedJanuary 19,2020.
  4. ^abcSarin (GB).Emergency Response Safety and Health Database. National Institute for Occupational Safety and Health. Accessed April 20, 2009.
  5. ^Anderson K (September 17, 2013).A Poisonous Affair: America, Iraq, and the Gassing of Halabja review of A Poisonous Affair: America, Iraq, and the Gassing of Halabja by Joost R. Hiltermann (Cambridge UP 2007).Lawfare: Hard National Security Choices(Report).RetrievedDecember 30,2015.... death can occur within one minute of direct inhalation as the lung muscles are paralyzed.
  6. ^Smith M (August 26, 2002)."Saddam to be target of Britain's 'E-bomb'".The Daily Telegraph.p. A18.RetrievedDecember 30,2015.The nerve agents sarin and VX. Colourless and tasteless, they cause death by respiratory arrest in one to 15 minutes.
  7. ^abVohra R (2022). "Organophosphorus and carbamate insecticides".Poisoning & Drug Overdose(8th ed.). McGraw Hill.
  8. ^Gussow L (July 2005). "Nerve Agents: Three Mechanisms, Three Antidotes".Emergency Medicine News.27(7). Alphen aan den Rijn, Netherlands:Wolters Kluwer:12.doi:10.1097/00132981-200507000-00011.
  9. ^ab"Facts About Sarin".Centers for Disease Control and Prevention.November 18, 2015.RetrievedMarch 20,2024.
  10. ^Shim TM, McDonough JH (May 2000)."Efficacy of biperiden and atropine as anticonvulsant treatment for organophosphorus nerve agent intoxication"(PDF).Archives of Toxicology.74(3): 165–172.doi:10.1007/s002040050670.PMID10877003.S2CID13749842.Archivedfrom the original on September 23, 2017.RetrievedApril 29,2018.
  11. ^Abu-Qare AW, Abou-Donia MB (October 2002). "Sarin: health effects, metabolism, and methods of analysis".Food and Chemical Toxicology.40(10). Amsterdam, Netherlands:Elsevier:1327–33.doi:10.1016/S0278-6915(02)00079-0.PMID12387297.
  12. ^Millard CB, Kryger G, Ordentlich A, et al. (June 1999). "Crystal Structures of Aged Phosphonylated Acetylcholinesterase: Nerve Agent Reaction Products at the Atomic Level".Biochemistry.38(22): 7032–9.doi:10.1021/bi982678l.PMID10353814.S2CID11744952..SeeProteopedia1cfj.
  13. ^Hörnberg A, Tunemalm AK, Ekström F (2007). "Crystal Structures of Acetylcholinesterase in Complex with Organophosphorus Compounds Suggest that the Acyl Pocket Modulates the Aging Reaction by Precluding the Formation of the Trigonal Bipyramidal Transition State".Biochemistry.46(16): 4815–4825.doi:10.1021/bi0621361.PMID17402711.
  14. ^Baselt RC, Cravey RH (2017).Disposition of Toxic Drugs and Chemicals in Man.Seal Beach, California: Biomedical Publications. pp. 1926–1928.ISBN978-0-8151-0547-3.
  15. ^Jakubowski, et al. (July 2003).Fluoride Ion Regeneration of Sarin (GB) from Minipig Tissue and Fluids Following Whole-Body GB Vapor Exposure(PDF)(Report). United States Army.Archived(PDF)from the original on January 2, 2016.RetrievedMarch 20,2024.
  16. ^Degenhardt, et al. (July 2004)."Improvements of the Fluoride Reactivation Method for the Verification of Nerve Agent Exposure".Journal of Analytical Toxicology.28(5). Oxfordshire, England:Oxford University Press:364–371.doi:10.1093/jat/28.5.364.PMID15239857.
  17. ^"Sarin gas as chemical agent – ThinkQuest- Library".Archived fromthe originalon August 8, 2007.RetrievedAugust 13,2007.
  18. ^Inns RH, NJ Tuckwell, JE Bright, TC Marrs (July 1990). "Histochemical Demonstration of Calcium Accumulation in Muscle Fibres after Experimental Organophosphate Poisoning".Hum Exp Toxicol.9(4): 245–250.Bibcode:1990HETox...9..245I.doi:10.1177/096032719000900407.PMID2390321.S2CID20713579.
  19. ^Lukey BJ, Romano JA Jr, Salem H (April 11, 2019).Chemical Warfare Agents: Biomedical and Psychological Effects, Medical Countermeasures, and Emergency Response.CRC Press.ISBN978-0-429-63296-9.
  20. ^Toxicology NR (1997).Review of Acute Human-Toxicity Estimates for GB (Sarin).National Academies Press (US).
  21. ^Bide RW, Armour SJ, Yee E (2005). "GB toxicity reassessed using newer techniques for estimation of human toxicity from animal inhalation toxicity data: new method for estimating acute human toxicity (GB)".Journal of Applied Toxicology.25(5): 393–409.doi:10.1002/jat.1074.ISSN0260-437X.PMID16092087.S2CID8769521.
  22. ^Lukey BJ, Romano JA Jr, Salem H (April 11, 2019).Chemical Warfare Agents: Biomedical and Psychological Effects, Medical Countermeasures, and Emergency Response.CRC Press.ISBN978-0-429-63296-9.
  23. ^abcUS Army Field Manual 3–11.9 Potential Military Chemical/Biological Agents and Compounds.United States Department of Defense. 2005.
  24. ^US Army Field Manual 3–9 Potential Military Chemical/Biological Agents and Compounds.United States Department of Defense. 1990. p. 71.
  25. ^Corbridge DE (1995).Phosphorus: An Outline of its Chemistry, Biochemistry, and Technology.Amsterdam, Netherlands:Elsevier.ISBN0-444-89307-5.
  26. ^abKovarik Z, Radić Z, Berman HA, Simeon-Rudolf V, Reiner E, Taylor P (March 2003)."Acetylcholinesterase active centre and gorge conformations analysed by combinatorial mutations and enantiomeric phosphonates".Biochemical Journal.373(Pt. 1). London, England:Portland Press:33–40.doi:10.1042/BJ20021862.PMC1223469.PMID12665427.
  27. ^abBenschop HP, De Jong LP (1988). "Nerve agent stereoisomers: analysis, isolation and toxicology".Accounts of Chemical Research.21(10). Washington DC:American Chemical Society:368–374.doi:10.1021/ar00154a003.
  28. ^abcdOffice of the Under Secretary of Defense for Acquisition and Technology (February 1998)."Chemical Weapons Technology"(PDF).The Militarily Critical Technologies List Part II: Weapons of Mass Destruction Technologies (ADA 330102).U.S. Department of Defense.RetrievedSeptember 4,2020– viaFederation of American Scientists.
  29. ^abKirby R (January 2006)."Nerve Gas: America's Fifteen Year Struggle for Modern Chemical weapons"(PDF).Army Chemical Review.Archived fromthe original(PDF)on February 11, 2017.RetrievedDecember 29,2015.
  30. ^The Determination of Free Base in Stabilised GB(PDF).United Kingdom: UK Ministry of Supply. 1956.Archived(PDF)from the original on August 28, 2014.RetrievedMarch 20,2024.
  31. ^Tu A."New Information Revealed By Aum Shinrikyo Death Row Inmate Dr. Tomomasa Nakagawa"(PDF).
  32. ^Seto Y (June 2001)."The Sarin Gas Attack in Japan and the Related Forensic Investigation".OPCW.
  33. ^Chemical agent and munition disposal summary of the U.S. army's experience(PDF).United States Army. 1987. pp. B-30.Archived(PDF)from the original on July 19, 2015.
  34. ^Hedges M (May 18, 2004)."Shell said to contain sarin poses questions for U.S."Houston Chronicle.p. A1.Archivedfrom the original on October 12, 2015.RetrievedDecember 30,2015.
  35. ^cit-OPDC. The preparatory manual to chemical warfare. Vol 1: Sarin.
  36. ^"Toxic Substances Portal – Diisopropyl Methylphosphonate (DIMP)".Agency for Toxic Substances and Disease Registry.
  37. ^"Nerve agents".OPCW.
  38. ^Housecroft CE, Sharpe AG (2000).Inorganic Chemistry(1st ed.). New York: Prentice Hall. p. 317.ISBN978-0-582-31080-3.
  39. ^Ian Sample,The Guardian,September 17, 2013,Sarin: the deadly history of the nerve agent used in Syria
  40. ^"Stability of Iraq's Chemical Weapon Stockpile".United States Central Intelligence Agency. July 15, 1996.RetrievedAugust 3,2007.
  41. ^Russell Goldmanpril (April 6, 2017)."Key Points on Sarin: The 'Most Volatile' of Nerve Agents".New York Times.
  42. ^Richard J. Evans (2008).The Third Reich at War, 1939–1945.Penguin. p.669.ISBN978-1-59420-206-3.RetrievedJanuary 13,2013.
  43. ^"A Short History of the Development of Nerve Gases".Noblis.Archived fromthe originalon April 29, 2011.
  44. ^Georg F (2003).Hitler's Miracle Weapons: The Secret History Of The Rockets And Flying Crafts Of The Third Reich; from the V-1 to the A-9: Unconventional Short- and Medium-Range Weapons.Helion. p. 49.ISBN978-1-87-462262-8.
  45. ^"Nerve gas death was 'unlawful'".BBC News Online.November 15, 2004.
  46. ^abBlixen S (January 13, 1999)."Pinochet's Mad Scientist".Consortium News.
  47. ^"Towley reveló uso de gas sarín antes de ser expulsado de Chile".El Mercurio(in Spanish). September 19, 2006.
  48. ^"Plot to kill Letelier said to involve nerve gas".New York Times.December 13, 1981.RetrievedJune 8,2015.
  49. ^"1988: Thousands die in Halabja gas attack".BBC News.March 16, 1988.RetrievedOctober 31,2011.
  50. ^"Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on their Destruction".Organisation for the Prohibition of Chemical Weapons.RetrievedMarch 27,2011.
  51. ^Organisation for the Prohibition of Chemical Weapons (November 30, 2016)."Annex 3".Report of the OPCW on the Implementation of the Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on Their Destruction in 2015 (Report). p. 42.RetrievedMarch 8,2017.
  52. ^Amy E. Smithson and Leslie-Anne Levy (October 2000)."Chapter 3 – Rethinking the Lessons of Tokyo".Ataxia: The Chemical and Biological Terrorism Threat and the US Response (Report).Henry L. Stimson Centre.pp. 91, 95, 100. Report No. 35. Archived fromthe originalon September 24, 2015.RetrievedJanuary 6,2017.
  53. ^Martin A (March 19, 2018)."1995 Aum sarin attack on Tokyo subway still haunts, leaving questions unanswered".The Japan Times Online.
  54. ^"More of Kremlin's Opponents Are Ending Up Dead".The New York Times.August 21, 2016.
  55. ^Ian R Kenyon (June 2002)."The chemical weapons convention and OPCW: the challenges of the 21st century"(PDF).The CBW Conventions Bulletin(56). Harvard Sussex Program on CBW Armament and Arms Limitation: 47.
  56. ^Brunker M (May 17, 2004)."Bomb said to hold deadly Sarin gas explodes in Iraq".MSNBC.RetrievedAugust 3,2007.
  57. ^Barnard A (March 19, 2013)."Syria and Activists Trade Charges on Chemical Weapons".The New York Times.RetrievedMarch 19,2013.
  58. ^Murphy J (September 5, 2013)."Cameron: British scientists have proof deadly Sarin gas was used in chemical weapons attack".The Daily Telegraph.Archivedfrom the original on September 6, 2013.
  59. ^"Syria: Thousands suffering neurotoxic symptoms treated in hospitals supported by MSF".Médecins Sans Frontières.August 24, 2013.Archivedfrom the original on August 26, 2013.RetrievedAugust 24,2013.
  60. ^"NGO says 322 died in Syria 'toxic gas' attacks".AFP. August 25, 2013.RetrievedAugust 24,2013.
  61. ^"Bodies still being found after alleged Syria chemical attack: opposition".Dailystar.com.lb. Archived fromthe originalon March 5, 2019.RetrievedAugust 24,2013.
  62. ^"Chemical attack of 4 April 2017 (Khan Sheikhoun): Clandestine Syrian chemical weapons programme"(PDF).RetrievedApril 26,2017.
  63. ^Chulov M (September 6, 2017)."Syrian regime dropped sarin on rebel-held town in April, UN confirms".The Guardian.ISSN0261-3077.RetrievedDecember 29,2017.
  64. ^OPCW Issues Fact-Finding Mission Reports on Chemical Weapons Use Allegations in Douma, Syria in 2018 and in Al-Hamadaniya and Karm Al-Tarrab in 2016(Report). Organisation for the Prohibition of Chemical Weapons. July 6, 2018.RetrievedJuly 14,2018.
  65. ^"U.S. destroys last of its declared chemical weapons".CBS.July 7, 2023.RetrievedJuly 11,2023.
edit