Tocopherol & tocotrienol standard/extract

[krisradh1432]

Hi guys, need to know your opinions.

I'm working with tocopherol/tocotrienol extract from cereals sources.
I extract the compounds using hexane and isopropanol before analysis with NP-HPLC.
Since the sample preparation takes more than three hours, i only able to inject two samples per day.
Sample 1 preparation- HPLC analysis- sample 2 preparation- HPLC analysis /// per day

My question is can I extract the compounds and store at -20C and inject at the end of day or the next day.
For example, I extract compounds from 3-4 samples sequentially, store at refrigerator and finally inject the
samples. Will the result vary with instant injection. Can any1 suggest me to improve number of sample preparation
per day.


Thanks in advance,
Mike

[tom jupille]

Most extraction procedures can be run in parallel, assuming the final solution is stable (which you seem to suggest may be a problem). It should only take an afternoon to find the answer; prep a sample and then make successive injections. That should give you the information you need.

[krisradh1432]

ok thanks for your reply. Now I am running stablity test for the tocols extract to see the changes over time and day period.
As i concern, some extract instable after extracted from its matric and each compounds have it stability strenght. So better for me to
study the effect of time to the extract.

Thank you

[JGK]

Are you allowing the samples to re-equilibrate to room temp after you remove them from the refrigerator? Differences in sample temperature may cause injection variability.


We run Tocopherol and Tocotrienol determination in oil samples regularly and do not seem to have an issue. Our samples are basically Hexane dilutions of the oils.only.

[krisradh1432]

Thanks for your replies.
I can run parallel saponification at one time, however i only can do one extraction, drying and redilution at one time.
This makes me to prepare one sample then inject into HPLC follow by another sample preparation. It really decreases my number of runs per day as my research is about vitamin E extraction optimization from wheat sample. I have to run hundreds of hplc injections. arrrr. I feel better to prepare all injections for the day before start the injection ( extract, dry and redilute with hexane). am what I say correct?

For how long the tocols extract in hexane (placed in vial for injection) stored at room temperature (25C) can stay stable.
Tat the reason why I asking whether the stability can be increased by keeping at freezing temperature.But prior to injection, the sample is allow to re-equilibrium by putting at room temperature or heating in water bath at 30C.
I am new to HPLC, that the reason why so many questions come into my mind.
Thanks Sir.

Good Day.