Determination of retinoic acid and retinol at physiological concentration by HPLC in Caucasians and Japanese women.

: A sensitive, specific and simple method for simultaneous determination of retinoic acid and retinol in human serum by reverse phase HPLC with UV detector has been developed. Retinoic acid is measurable at physiological concentration in human serum by this method. There is no significant difference in serum retinoic acid level between Caucasian and Japanese subjects. However, the serum retinol level in Japanese women is significantly lower than that in Caucasian women.