Toshio Masui

High-performance liquid chromatographic determination of six p-hydroxybenzoic acid esters in cosmetics using Sep-Pak florisil cartridges for sample pre-treatment.

A rapid and simple method is described for the simultaneous determination of methyl, ethyl, isopropyl, n-propyl, isobutyl and n-butyl p-hydroxybenzoic acid esters (parabens) in cosmetics by high-performance liquid chromatography (HPLC). The method involves a single extraction of parabens with diethyl ether and clean-up on a Sep-Pak Florisil cartridge. Fat-soluble excipients in the diethyl ether extracts are removed through the cartridges with hexane-chloroform (75:25). Parabens are then eluted from the cartridges with hexane-ethyl acetate (70:30) and determined by HPLC on a reversed-phase column with water-methanol (50:50) as the mobile phase using sec.-butylpraben as an internal standard. The method was applied to samples with complicated matrices such as cream, milk lotion, lotion and cleansing foam, and the recoveries were 99.0-102.3% with coefficients of variation of 0.3-1.2%.

Contents of Eicosapentaenoic Acid and Docosahexaenoic Acid in “Health Food”

A simple method for the determination of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in “health food” contained EPA by gas liquid chromatography (GC) was developed.A sample of 100mg was methyl-esterified by the boron trifluoride-methanol (BF3-MeOH) method and the product was extracted with hexane containing triphenyl ethylene as an internal standard. The sample solution was determined by GC on a 10% Silar 10C column. Recoveries of EPA and DHA added to oils were in the range of 98.8-107% and 98.8-122%, respectively. The present method was applied to “health food” contained EPA. The results showed thet the quantities of EPA and DHA (mg) per gram of oils and fats of the supplements were 20.3 and 11.4 on average, respectively.Moreover, the fatty acid composition, acid value (AV), peroxide value (POV) and tocopherols (Toc) in the “health food” were investigated. Though the “health food” is easily taken, from the viewpoint of safety, nutritional balance and price, EPA and DHA should be taken in the diet in the form of sardines, mackerels, and so on.