Chromatography Forum

Hello to all,
Im working with a drug product and I want to remove the NaCl excipient from my sample to proceed to IC analysis.
Anyone can help me with any idea how can I get rid off the NaCl?

Thnx in advance

Hi

I think that we need some more information on your analyte, its solubility in organic and aqueous solvents and the other excipients.

Having said that, if your target analyte is soluble in, say for example, water or methanol or hexane or dichloromethane then 4 possible approaches that spring to mind are

1. Addition of AgNO3 to precipitate the salt - but that would leave NO3 ions
2. Dissolving the sample in an organic solvent and back washing with water
3. Passing the sample in solution through a simple disposable ion exchange cartridge
4. The obvious one that I hadn't thought of

Regards

Ralph

In the past I used Sephadex G-15 (if they still make it) to desalt liquids prior to HPLC analysis.

Our unpurified product contains various organic salts, including benzamide, isobutyramide, and ammonium acetate which are utilized during synthesis to protect both the backbone and the bases.

Hello to all,
Im working with a drug product and I want to remove the NaCl excipient from my sample to proceed to IC analysis.
Anyone can help me with any idea how can I get rid off the NaCl?
Thnx in advance

When we were assaying for sodium isethionate by IC, I found that chloride in the sample (chloride is extremely common in most consumer products, often used to adjust viscosity), I used silver resin clean up cartridges (removed all halides), were from Alltech so changed hands a bit in last 15 years, so similar to this http://www.envexp.com/products/12-Chrom ... cc%2C_50pk

I am analyzing ethylene glycol in brine water samples on GCFID and this is fouling the inlet quickly. Is there a way to remove the salts and leave the glycols? Or an extraction I am not aware of? This is probably best run on HPLC but we don't have one here.

Did you try the above cartridges? They have a cost, but so does your time to clean inlet or change liners.

How about mixing your samples with solvent like IPA or similar, a solvent which will cause the NaCl to precipitate?

CPG- I have the cartridges on the way, but they say it only removes 10mg salt/cartridge, and my samples average 100mg/ml.

I have tried mixing with methanol which does drop the salt out, but that also dilutes the sample and raises reporting levels.

Different matrix I know (alcoholic beverages), but we extract the glycols into ethyl acetate and analyse that admittedly by MS rather than FID.

Didn't think they would come out of water, Andy. Just simple shake extraction?

Didn't think they would come out of water, Andy. Just simple shake extraction?

Pretty much, though the sample is saturated with ammonium sulphate prior to vortexing.

I am analyzing ethylene glycol in brine water samples on GCFID and this is fouling the inlet quickly. Is there a way to remove the salts and leave the glycols? Or an extraction I am not aware of? This is probably best run on HPLC but we don't have one here.

What levels of ethylene glycol are you looking for? I know that for trace levels of glycerin we dissolved samples in DMF and derivatized with BSTFA, then assayed by GC-FID and could detect pretty low levels.

And for trace ethylene glycol in glycerin using a now-updated USP procedure, we could also dissolve sample in methanol and quantitate low levels of ethylene glycol.