I'm having trouble to determinate the content of Choline Chloride (water extraction) using an C-18 column, detector UV visible, wavelength 214 nm .
any different methods?
Hello Giulia,
can you describe your method and the problems associated with it in more detail? So your question is very general and you will probably only get a very general answer.
Regards
Markus
Markus Christ the problem that I'm facing is that the peak isn't pure, probably because I'm working with a wavelength that detect kinda of everything. The process is very easy I dissolve the product in water, see that the choline is soluble in water, filter it and inject in the HPLC.
I'm using
colum: C18 Sunfire water
mobile phase: water/methanol/ Heptafluorobutyric acid
I tried to search other methods in literature but without luck.
You know what you are supposed to detect. Therefore, you could just do a UV-Vis and see the absoranbce. Also, you might do a scan and see whether there are multiple peaks.
That will let you know whether your peak has multiple compounds.
Hi Giulia,
have you ever thought about ion chromatography? So, as you write here, you have a problem with co-elution. LC in combination with MS in SIM mode would also be an alternative. Maybe HILIC would be also an alternative instead of RP. RP and charged molecules are often an ungrateful pairing. Ion pair reagents do not always make things better. However, you have to solve the problem with co-eluting. Other phases usually have different selectivities.
Article Determination of betaine, choline and trimethylamine in feed...
Good luck.
Regards
Markus
Dear Giulia Martini
many thanks for your question. As indicated one of the better methods to determine choline is ion exchange chromatography. To be specific cation exchange chromatography and detect choline using suppressed conductivity. This approach is highly sensitive and very selective.
There are methods out there to determine choline in pharmaceutical formulations and food & beverage products. In general, the methods apply some cation exchange separation using high capacity columns, ensuring large matrix tolerance and high sample load (leading to low LoDs). Depending on the complexity of the sample matrix isocratic or gradient elution is applied. For food samples, the differentiation between total, bound, and free choline is possible, after having processed the sample (e.g., running an acidic digest).
In order to give you some starting points for your evaluation, I thought you might like the LINKs in the following.
I hope this helps.
Best regards, Detlef.
Pharma. Formulation:
https://assets.thermofisher.com/TFS-Assets/CMD/Application-Notes/an-72649-ic-limit-choline-test-an72649-en.pdf
Food & Beverage:
https://assets.thermofisher.com/TFS-Assets/CMD/Application-Notes/AU-189-IC-Choline-Infant-Form-AU70163-EN.pdf
https://assets.thermofisher.com/TFS-Assets/CMD/Application-Notes/AU-193-IC-Choline-Infant-Formula-Adult-Nutritionals-AU70918-EN.pdf
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