I used 100 mg dry soybean seed powder for extraction, and i was able to detect alpha tocopherol which is actually 10% of total seed Vit E when i optimized my extraction. But lately, i was not able to detect the alpha T signal with exactly same extraction procedure. I increased injection volumes, increased the startup seed material to 200 mg which did not seem to show the signals. However, my gamma and delta tocopherols look good. I am just worried, if my extraction is not working or the levels of alpha T has fallen below the detection limits in my lines?
Which extraction are you using? Did you try with MeOH/H2O?
Also, what about the standards?
Thanks Albert. The standards look great. Because tocopherols are lipophilic, i continued to using ethanol, MeOh/H2O would be too polar for extraction of tocopherols. The gamma T and delta T has fallen to half of the levels compared to my previous results from 6 months ago from same tissue. Further more i cannot even find a trace of alpha T in recent analysis. Do you think, the detector is emitting less light compared to 6 months ago?
Kranthi, I'm not into soybean analysis, but one thing which came to my mind is the following: Are you using the same strain of soybeans / soybean seed? I know from lipidomic analysis in different strains of mice that there can be huge differences due to the strain used.
Hello Mr. Chebrolu,
have you seen this publication?
http://www.sciencedirect.com/science/article/pii/S0889157512000518
May be in these seeds content of alpha tocopherol is very low. I think you have to increase the amount of sample. Which wavelengths of extiction and emission are using? Have you tried the extraction by saponification?
The concentration I do not think it would be a big problem... 100-200mg of dried material is quite a lot.
I am used to weight less than that, (30-50mg) and I detect tocopherols in metabolomics analyses.
Do you have the change to try the analyses with LC-MS?
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