Chromatography Forum

dear all, we have got problem with hazy sample solution. filtration and centrifugation cannot produce clear solution. i have an idea about aggregation followed by filtration, but i do not know how to obtain the particle aggregates. does anyone help me? thanks in advance.

Your hazy solution can be result of emulsion and not suspension. Try to add THF and see what happens.

Ultrafiltration? But please be aware that you may have a severe complication here, regarding analysis of any (partially??) dissolved substances.

What have you tried for filtration? What is the solvent of your solution?

Cah you tell us what it is you are disolving? This may help come up with an answer.

we want to determine B12 in multivitamin tablets. due to its small quantity we use small volume of solvent (pH 4-5 aqueous buffer) to obtain B12 in its working concentration that be able to quantity using LC. we found hazzy solution that could not be cleaned by centrifugation or filtration.

Look at the ingreedients list for items that are not soluable in water. That may give you some ideas. This would include both organic and inorganic compunds.

Hi Syx,

If the multivitamin tablets contain some or all of the following vitamins A, D, E and K, which are fat- soluble the resultant “solutionâ€

it does not contain lipid-soluble vitamins. the active ingredients are water soluble vitamins and minerals.

What are the inactive ingreedients?

excipients that commonly be used in capsule formulations. some active ingredients are coated separately with unknown polymer(s) to avoid interaction with other substances in the formulation.

Well, the polymers are a good candidate for being the problem. Perhaps a solvent change will either make the polymer dissolve or agrregate?