Vitamin E is an active ingredient in our cream product. We are trying to develop an HPLC method, but having some problems. We use an Internal Standard method. Does anyone have any suggestions?
Thank you.

Go to www.waters.com and check the applications bibliography. There are many references for the analysis of Vitamin E by HPLC.

Assay of vitamin A palmitate and vitamin E acetate in cosmetic creams and lotions by supercritical fluid extraction and HPLC.

Author: Scalia, Santo; et al
Source: J. Pharm. Biomed. Anal. / Year: 1995 / Volume: 13(3) /Page: 273

A question, does no one search the literature anymore before they feel they have to ask for help?

If your looking for an HPLC method for Vitamin E (Alpha-tocopherol), we use Vitamin E Acetate as an ISTD. HPLC conditions: 98 Methanol/ 2 Water @ 2.0 ml/min. Using a 25.0 cm x 4.46 mm. Supelco LC18 @ 280 nm. You will get seperation of delta, gamma and alpha tocopherol at 6.14, 7.13 and 8.24, respectively. Vitamin E acetate will elute at 10.88.

We quantitate vitamin E acetate using 5u Brownlee RP-8 columns 10cm x 4.6mm with 5u guard cartridge using about 95% ACN 5%H2O at 1.00 ml/min. at 284 nm. It works quite well. Samples and standards are made up in DMF.

Is a fluorescence detector available?
lambda ecc = 295 nm, lambda emiss = 330 nm for Vitamin E acetate

HPLC conditions:
RP separation is easy but nasty (LC-8-DB 75 x 4.6mm 3mcm, gradient from 20% 0.02M TFA / 80% CH3CN to 5% / 95%) since the column is likely not to be working properly;
better conditions in Straight Phase (Phenomenex Luna Si(2) 150x4.6mm 3mcm, gradient using n-hexane / ethyl acetate) due to the solubility of Vit. E in hydrophobic media.