Hydroxypropyl tetrahydropyrantriol （HT） is a xyloside derivative and the main active ingredient of pro-xylane, an anti-aging cosmetic raw material. HT has two diastereomeric configurations, （β, S） and （β, R）. The steric configuration of （β, S） and （β, R） is different, and so are their bioactivity, in vivo degradation and safety. （β, S） is the dominant configuration and its biological activity is significantly higher than that of the mixture of （β, S） and （β, R）. In this study, a method for the determination of （β, S） in cosmetics by high performance liquid chromatography with evaporative light-scattering detector （HPLC-ELSD） was established. Samples were separated by an Agilent Polaris 5 Amide-C18 （250 mm×4.6 mm, 5 μm） column with 0.05% formic acid aqueous solution as the mobile phase. The results show that （β, S） and （β, R） can be separated with a resolution （R）>1.5. （β, S） is quantified by the external standard method, and the linear relationship of the compound is good in the range of 10.0 mg/L to 300.0 mg/L. The correlation coefficient （r） is greater than 0.999. The limit of detection （LOD） and quantification （LOQ） were 0.15 mg/g and 0.5 mg/g, respectively. The recoveries of （β, S） are investigated in water-in-oil, oil-in-water, and aqueous solution cosmetic samples at three spiked levels （2.5, 5.0, and 10.0 mg/g）. The recoveries range from 94.4% to 100.1%. The practicability of the method was examined by using 18 batches of commercially available cosmetics with HT on the ingredient label. Ten batches are found to contain （β, S） at the concentrations ranging from 0.1% to 10.6%, and both （β, S） and （β, R） are found in 6 batches. The method has the advantages of simple operation, accurate quantification, and effective separation of isomers. It is suitable for the determination of （β, S） content and diastereomer distribution of （β, S） and （β, R） in HT cosmetics. It can also provide effective technical references for market supervision and product quality control.
