If this reagent is to be stored in the frozen state,
preferably it should be divided into aliquots.
Do not freeze/thaw more than once.
When the reagent is freshly prepared it may be light yellow or light pink in colour.
It will develop a stronger pink colour over 2-3 months at 4°C.
The absorbance of this solution should be less than 0.05 when read against distilled water.