One year ago I made a micronutrient stock solution for MS medium and the solution appeared colorless. Yesterday I made the solution with the same composition but the solution turned yellowish. What caused it ?
Composition:
CuSo4.5H2O
Na2MoO4.2H2O
H3BO3
MnSO4.4H2O
KI
ZnSO4.7H2O
CoCl2.6H20