Chromatography Forum

We have recently purchased a riboflavin (vitamin B2) analytical standard which conforms to ISO Guide 34 and are having trouble dissolving normally in warm dilute acetic acid as in AOAC 970.65. Has anyone else experienced this and how were you able to dissolve the standard? Any help is greatly appreciated. Thanks.

The method calls for 50 mg B2 in 300 ml of heated acetic acid with frequent agitation. Keep heating until the standard goes into solution. Is this the procedure that you are following?

Also, you may want to try ultra-sonication; however, be sure to use cold water in the sonicator bath. Put the vol flask containing your solvent and powdered vitamin in the sonicator with cold water bath and sonicate for 5 to 10 mins with regular shaking. I've used this with cyanocobalamin vit b12, which was also difficult to solvate.

The method calls for 50 mg B2 in 300 ml of heated acetic acid with frequent agitation. Keep heating until the standard goes into solution. Is this the procedure that you are following?

Yes, this is the procedure we are following, but it does not want to dissolve.

Also, you may want to try ultra-sonication; however, be sure to use cold water in the sonicator bath. Put the vol flask containing your solvent and powdered vitamin in the sonicator with cold water bath and sonicate for 5 to 10 mins with regular shaking. I've used this with cyanocobalamin vit b12, which was also difficult to solvate.

I think that we have tried ultrasonic bath, but I will double-check this. Planning an experiment on Monday, so maybe I will have some news then.

Maybe one more note is that we can dissolve USP riboflavin standard with no problems for many years. Only since we have gone ISO 17025 did we try guide 34 standard.