Poor recovery of cyanocobalamin

[dewish]

Hi all,
I am trying to develop a method for the analysis of cyanocobalamin in a capsule. The capsule also contains folic acid, ferrous gluconate, manganese sulfate, cupric sulfate, ascorbic acid, and neosorb P60W. The cyanocobalamin content in the capsule is very low (7.5ug in 430mg). I diluted the capsule content with 20mL water, sonicated the mixture for 10 minute, and filtered it with 0.45um filter. All preparation was done in the dark. It was very visible that the capsule content was not dissolved well in the solvent. With this sample prep method I was able to detect cyanocobalamin at 550nm but having a very poor recovery (~30%). Does anyone have any prep method that works well to dissolve cyanocobalamin and have a good recovery percentage. Thanks!!

[bunnahabhain]

Hi dewish

The usual way to go would be:
- Add some organic to the extraction solvent (maybe the initial mobile phase composition of your analytical method?)
- Add a bit of acid
And see if and how the recovery changes.

Joerg

[dewish]

Thanks Joerg!! I 'll try that

Dewi

[James_Ball]

I did a vitamin B study a while back and found this paper very helpful in working out the extraction technique. I found that I needed acid extraction for B1, B6 and akali extraction for B3. He gives a comparison of the different extraction techniques for each vitamin and I believe B12 is included. It can be found fairly easily with an internet search. I hope it helps.


Mal J Nutr 2: 176-194, 1996
Simultaneous determination of B-vitamins and ascorbic acid in multi-vitamin preparations by reversed-phase HPLC
Tee E-Siong and Khor Swan-Choo
Division of Human Nutrition, Institute for Medical Research, 50588 Kuala Lumpur