You are using an unsupported browser. Please upgrade your browser to a newer version to get the best experience on Database of hazardous chemicals.
Record Information
Creation Date2009-03-06 18:58:29 UTC
Update Date2016-11-09 01:08:12 UTC
Accession NumberCHEM000258
Common NameMethylarsonic acid, monosodium salt
ClassSmall Molecule
DescriptionMethylarsonic acid, monosodium salt is an organoarsenic compound formed from the methylation of inorganic arsenic by living organisms. AArsenic is a chemical element that has the symbol As and atomic number 33. It is a poisonous metalloid that has many allotropic forms: yellow (molecular non-metallic) and several black and grey forms (metalloids) are a few that are seen. Three metalloidal forms of arsenic with different crystal structures are found free in nature (the minerals arsenopyrite and the much rarer arsenolamprite and pararsenolamprite), but it is more commonly found as a compound with other elements. (3, 9)
Contaminant Sources
  • IARC Carcinogens Group 3
  • T3DB toxins
Contaminant Type
  • Arsenic Compound
  • Household Toxin
  • Organic Compound
  • Organometallic
  • Pesticide
  • Synthetic Compound
Chemical Structure
Methylarsonate, monosodium saltGenerator
Disodium methanearsonateMeSH
Monomethylarsonic acid, dimercury (1+) saltMeSH
Monomethylarsonic acid, dipotassium saltMeSH
Monomethylarsonic acid, iron (2+) salt (3:2)MeSH
Monomethylarsonic acid, monosodium saltMeSH
Sodium methanearsonateMeSH
Methylarsonous acidMeSH
Monomethylarsonic acidMeSH
Methanearsonic acidMeSH
Methylarsonic acidMeSH
Monomethylarsonic acid, calcium salt (2:1)MeSH
Monomethylarsonic acid, iron saltMeSH
Monomethylarsonic acid, ammonium, iron (3+) saltMeSH
Monomethylarsonic acid, disodium saltMeSH
Monomethylarsonic acid, monoammonium saltMeSH
Monomethylarsonic acid, monocalcium saltMeSH
Monomethylarsonic acid, zinc saltMeSH
Chemical FormulaCH4AsNaO3
Average Molecular Mass161.952 g/mol
Monoisotopic Mass161.927 g/mol
CAS Registry Number2163-80-6
IUPAC Namesodium hydrogen methylarsonate
Traditional NameMSMA
InChI IdentifierInChI=1S/CH5AsO3.Na/c1-2(3,4)5;/h1H3,(H2,3,4,5);/q;+1/p-1
Chemical Taxonomy
Description belongs to the class of organic compounds known as pentaorganoarsanes. These are organoarsenic compounds containing an arsenic compound that is pentasubstituted by only organic groups.
KingdomOrganic compounds
Super ClassOrganometallic compounds
ClassOrganometalloid compounds
Sub ClassOrganoarsenic compounds
Direct ParentPentaorganoarsanes
Alternative Parents
  • Pentaorganoarsane
  • Alkylarsine oxide
  • Oxygen-containing organoarsenic compound
  • Organic alkali metal salt
  • Organic metalloid salt
  • Organic oxygen compound
  • Organopnictogen compound
  • Organic oxide
  • Hydrocarbon derivative
  • Organic sodium salt
  • Organic salt
  • Aliphatic acyclic compound
Molecular FrameworkAliphatic acyclic compounds
External DescriptorsNot Available
Biological Properties
StatusDetected and Not Quantified
Cellular Locations
  • Cytoplasm
  • Extracellular
Biofluid LocationsNot Available
Tissue LocationsNot Available
PathwaysNot Available
ApplicationsNot Available
Biological RolesNot Available
Chemical RolesNot Available
Physical Properties
AppearanceWhite powder.
Experimental Properties
Melting PointNot Available
Boiling PointNot Available
Solubility580 mg/mL at 20°C [TOMLIN,C (1997)]
Predicted Properties
Water Solubility384 g/LALOGPS
pKa (Strongest Acidic)5.18ChemAxon
Physiological Charge-1ChemAxon
Hydrogen Acceptor Count2ChemAxon
Hydrogen Donor Count1ChemAxon
Polar Surface Area46.53 ŲChemAxon
Rotatable Bond Count1ChemAxon
Refractivity10.68 m³·mol⁻¹ChemAxon
Polarizability9.68 ųChemAxon
Number of Rings0ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleYesChemAxon
Spectrum TypeDescriptionSplash Key
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Positivesplash10-03di-0900000000-7648859c5afc20c1c24eView in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Positivesplash10-03di-0900000000-5fb05151f59dbf8e0e89View in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Positivesplash10-01w0-2900000000-c3f95d0a6a82e2f35fa6View in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Negativesplash10-03di-1900000000-80daace3df2e1db7d06cView in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Negativesplash10-03di-2900000000-bf486a6d061ce33bc522View in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Negativesplash10-03kc-1900000000-ccf17348217245619a8cView in MoNA
Toxicity Profile
Route of ExposureOral (4) ; inhalation (4); dermal (4)
Mechanism of ToxicityArsenic and its metabolites disrupt ATP production through several mechanisms. At the level of the citric acid cycle, arsenic inhibits pyruvate dehydrogenase and by competing with phosphate it uncouples oxidative phosphorylation, thus inhibiting energy-linked reduction of NAD+, mitochondrial respiration, and ATP synthesis. Hydrogen peroxide production is also increased, which might form reactive oxygen species and oxidative stress. Arsenic's carginogenicity is influenced by the arsenical binding of tubulin, which results in aneuploidy, polyploidy and mitotic arrests. The binding of other arsenic protein targets may also cause altered DNA repair enzyme activity, altered DNA methylation patterns and cell proliferation. (2, 1)
MetabolismArsenic is absorbed mainly by inhalation or ingestion, as to a lesser extent, dermal exposure. It is then distributed throughout the body, where it is reduced into arsenite if necessary, then methylated into monomethylarsenic (MMA) and dimethylarsenic acid (DMA) by arsenite methyltransferase. Arsenic and its metabolites are primarily excreted in the urine. Arsenic is known to induce the metal-binding protein metallothionein, which decreases the toxic effects of arsenic and other metals by binding them and making them biologically inactive, as well as acting as an antioxidant. (5)
Toxicity ValuesNot Available
Lethal DoseNot Available
Carcinogenicity (IARC Classification)3, not classifiable as to its carcinogenicity to humans. (8)
Uses/SourcesMethylarsonic acid, monosodium salt is used as an herbicide and pesticide. (9)
Minimum Risk LevelAcute Oral: 0.005 mg/kg/day (7) Chronic Oral: 0.0003 mg/kg/day (7) Chronic Inhalation: 0.01 mg/m3 (7)
Health EffectsArsenic poisoning can lead to death from multi-system organ failure, probably from necrotic cell death, not apoptosis. Arsenic is also a known carcinogen, esepcially in skin, liver, bladder and lung cancers. (2, 5)
SymptomsExposure to lower levels of arsenic can cause nausea and vomiting, decreased production of red and white blood cells, abnormal heart rhythm, damage to blood vessels, and a sensation of burn (2).
TreatmentArsenic poisoning can be treated by chelation therapy, using chelating agents such as dimercaprol, EDTA or DMSA. Charcoal tablets may also be used for less severe cases. In addition, maintaining a diet high in sulfur helps eliminate arsenic from the body. (5)
Not Available
DrugBank IDNot Available
HMDB IDNot Available
FooDB IDNot Available
Phenol Explorer IDNot Available
KNApSAcK IDNot Available
BiGG IDNot Available
BioCyc IDNot Available
METLIN IDNot Available
PDB IDNot Available
Wikipedia LinkNot Available
Chemspider IDNot Available
ChEBI IDNot Available
PubChem Compound IDNot Available
Kegg Compound IDNot Available
YMDB IDNot Available
ECMDB IDNot Available
Synthesis ReferenceNot Available
MSDSNot Available
General ReferencesNot Available