L-Cysteine
Synonyms
Cysteine;
Cys;
EMA No. 3263;
L-2-Amino-3-mercaptopropanoic acid;
Category
Zwitterionic Surfactant
> Amino Acid Type
>> Amino acid and its Salts
Chemical Numbering System
CAS: 52-90-4
EINECS: 200-158-2
Molecular Formula & Molecular Weight
Molecular Formula: C3H7NO2S; C3H7N1O2S
Molecular Weight: 121.16
Structure
Properties
Appearance (1), white solid.
Solubility soluble in water.
Stability stable. Easily oxidized.
Risk Solid form: flammable material; irritation, irritation to skin, eye, respiratory system. Harmful products of combustion are CO, CO2 and so on. Contact with strong oxidants, can cause to burn.
GHS label: 
Animal Toxicity
Table 1 Animal toxicity values
|
mouse intraperitoneal LD50 |
1400mg/kg[1] |
|
mouse intravenous LD50 |
1250mg/kg[1] |
|
mouse oral LD50 |
660mg/kg[1] |
|
mouse subcutaneous LD50 |
1360mg/kg[1] |
|
rat intraperitoneal LD50 |
1620mg/kg[1] |
|
rat intravenous LD50 |
1140mg/kg[1] |
|
rat oral LD50 |
1890mg/kg[1] |
|
rat subcutaneous LD50 |
1550mg/kg[1] |
Reproductive effect[1].
Ecology may be hazardous to environment. Water body should be given special attention.
Biodegradability biodegradable.
Characteristics excellent anti-oxidizing, antistatic, dispersing abilities. Non-essential amino acid. Amino acid that make up proteins.
Synthesis
Quality Standards & Test Methods
1, Physical and chemical indexes
|
Item |
Physical and chemical indexes |
|
Solid |
|
|
Actives, %, ≥ |
95.0 |
Test Methods
(1), Actives
GB/T 13173 Surface active agents -- Detergents -- Testing methods
Ninhydrin method
2, Hazardous substances indexes
|
Item |
Hazardous substances indexes |
|
Solid |
|
|
Heavy metals (as Pb), mg/kg, ≤ |
20 |
|
As, mg/kg, ≤ |
3 |
Test Methods
(1), Heavy metals (as Pb)
Safety and Technical Standards for Cosmetics (2015 Edition)
GB/T 30799 The test method of food detergents -- Determination of heavy metals
(2), As
Safety and Technical Standards for Cosmetics (2015 Edition)
GB/T 30797 The test method of food detergents -- Determination of total arsenic
3, Further explanation
(a), On physical and chemical indexes: firstly, shall be indicated carbon atom distribution; secondly, shall be indicated average molecular weight.
(b), Used in cosmetics, should be test for harmful substances or furtherly test for microorganisms, according to local regulations and standards.
Major Uses
1, Typical applications
Use as antioxidant.
2, Personal care products
Conditioning agent, antioxidant, antistatic agent, hair waving or straightening agent, masking agent, reducing agent in personal care products.
3, Food
Use as food additive (perfume).
Manufacturers
References
[1]: ChemIDplus. 52-90-4, Cysteine
Update: 20190414(1);