Can somebody give us a hint how to analyse hydrogenated Castor oil (as triglyceride or methylester) in beauty care products.
The boiling seems to be too high to analyse it directly on a HT column and methylation (directly with BF3 or acid) or transesterification (KOH/methanol) gives non-reliable results.
By Rodney George on Wednesday, November 28, 2001 - 06:02 am:
Your non reliable results are do to what? Do you know? With proper technique the fatty acid analysis of any triglyceride mix is straightforward. Are you extracting them first?
Do your other incipients interfere?
You could certainly try HPLC with ELSD or RID.
Both GC and LC may require a sample prep before analysis.
Use organic base transesterification if possible, not the 2 step saponification-esterification.
Do not saponify or esterify your oil longer than necessary (8-10 min?) if you use the two step.
Follow it with a silylation of the 12-hydroxy group if you do GC
I have analysed linolenic acid triglycerides with excellent results so it can be done. Excessive heating will dimerize your ricinoleic acids. this will cause non-reproducible results.
If you just want to measure how much triglyceride is present, why not do TLC? How accurate do you need to measure? Lots of questions about your details make it hard to help. I hope I have.
By Anonymous on Wednesday, November 28, 2001 - 01:32 pm:
we've assayed triglycerides by HPLC-ELSD. we've also used GC with a high-temperature stainless steel capillary from Quadrex. 20 years ago we quantitated hydrogenated castor oil in solid antiperspirant by assaying for the combined glycerin (hyd. castor oil is 9.7% glycerin) by saponifying the sample to assay for combined glycerin. If your sample has free glycerin from lauramide DEA or has propylene glycol, also do a free glycerin assay and subtract out those meq/g.
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