LC Method for Diosgenin [August 26, 2004]

[admin]

LC Method for Diosgenin
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By Jan on Thursday, August 26, 2004 - 03:04 am:

Dear Forum members,
I have to check some nutritional supplements and cosmetic creams for the presence of DHEA (dehydroepiandrosterone) and / or diosgenin. DHEA should be no problem at just 50 % or so of acetonitrile on a C18 column (UV at 210 nm). Diosgenin, a larger steroidsaponin, seems more difficult. Does any of you have any experience with analysing diosgenin in nutraceuticals or Wild Yam (Dioscorea species) ? Preferably LC-UV.
Thanks
Jan

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By Uwe Neue on Thursday, August 26, 2004 - 03:02 pm:

What is the difficulty?

[mross]

Diosgenin has almsot no UV therefore HPLC with UV detector is not a good choice. There is some early work done on HPLC determination of diosgenin and related compounds using precolumn derivatisation.

[Jan007]

Just an update on my work (I am the original poster)
Apparently, diosgenin elutes only after about 5 minutes at 100 % acetonitrile on a 150 x2.1 mm 3 µm C18 column at 0.4 ml/min.
It can be seen at 205 nm, but the signal is weak (no real chromophore), even with ACN super gradient. I got better results with our Ion-Trap MS using positive electrospray. I find the molecular ion 415 and some in-source loss of H2O. Also MS2 and MS3 worked just fine. I am currently looking if I can get som reliable quantitative results from the MS signal. Will keep you posted.