|
L-Cystine
|
 |
|
C6H12N2O4S2
240.3 |
56-89-3 |
| DEFINITION |
|
Cystine contains not less
than 98.5 per cent and not more than the equivalent of 101.0
per cent of (R,R)-3,3’-dithiobis
(2-aminopropionic acid), calculated with
reference to the dried substance.
|
|
CHARACTERS
|
|
A white, crystalline powder,
practically insoluble in water and in alcohol. It
dissolves in dilute solutions of alkali hydroxides.
|
|
| IDENTIFICATION |
| Infrared absorption
spectrophotometry |
| TESTS |
| Appearance
of solution |
Clear and
meets the requirements |
|
Specific
optical rotation |
-218º to -224º |
| Ninhydrin-positive
substances |
Meets the requirements |
| Chlorides |
Limit: 200 ppm |
| Sulphates |
Limit: 300 ppm |
| Ammonium |
Limit:200 ppm |
| Iron |
Limit:10 ppm |
| Heavy
metals |
Limit:10 ppm |
| Loss
on drying |
Not more than 0.5 per
cent |
| Sulphated
ash |
Not more than 0.1 per
cent |
|
ASSAY |
98.5 per cent to 101.0 per
cent |
| STORAGE |
| Store in a well-closed
container, protected from light. |
