Objective:To determine the content of all-trans-retinyl palmitate in multivitamin preparations. Methods: HPLC was used and the chromatographic column was Apollo Silica (250 mm × 4. 6 mm, 5 μm). The mobile phase consisted of hexane-isopro-panol (999. 5:0. 5) and the column temperature was 30 ℃. The detection wavelength was 325 nm and the flow rate was 1. 0 ml· min-1 . The injection volume was 100 μl. Results:The calibration curve of all-trans-retinyl palmitate was linear within the concentra-tion range of 0. 2260-0. 6780 IU·ml-1(0. 1243-0. 3729 μg·ml-1, r=0. 9999). The average recovery was 99. 86%, and RSD was 0. 64%(n=9). Conclusion:The method is simple,accurate,sensitive,reproducible and universal, which can be used for the con-tent determination of all-trans-retinyl palmitate in multivitamin preparations.

OBJECTIVE:To improve HPLC method for determining optical isomers in raltitrexed raw material.METHODS:After improved,the column was CHIRALPAK AD-H with mobile phase consisted of n-hexane-anhydrous ethanol-trifluoroacetate (70∶30∶0.1,V/V/V).The sample size was 100 μL.The flow rate of 1.0 mL/min.The detection wavelength was set at 226 rm,and column temperature was 35 ℃.RESULTS:The linear range of optical isomers was 99.68-398.7 ng(r=0.999 9).The quantitation limit was 4.945 ng,and detection limit was 1.648 ng.RSDs of precision,stability and reproducibility tests were all lower than 1.0％;the recoveries ranged 99.43％-100.14％ (RSD=0.25％,n=9).CONCLUSIONS:The optimized method is simple,accurate,sensitive and reproducible,which can be used for the determination of optical isomers in raltitrexed raw material.