ABSTRACT
A cold saponification method for determination of 5 lutein stereoisomers in dairy products by high performance liquid chromatography ( HPLC ) was developed. Samples were cold-saponified at room temperature and extracted by n-hexane/petroleum/dichloromethane ( 2: 2: 1 , V/V/V ) . Then 5 lutein stereoisomers were separated on a YMC C30 column with gradient elution using methanol/methyl tert-butyl ether as the mobile phase, and data were acquired by a photodiode array detector at wavelength of 445 nm. The calibration curve was linear in the range of 0 . 127-5 . 082 mg/L with correlation coefficient of 0 . 9999 , and the recoveries were from 96 . 7% to 102 . 2% with the RSDs in the range of 4 . 1%-5 . 4% ( n=6 ) . The limit of detection was 0 . 010 μg/g ( S/N=3 ) , and the limit of quantification was 0 . 030 μg/g ( S/N=10 ) . By presenting results of good accuracy, precision and sensitivity, this method validates its suitability for routine analysis of 5 lutein stereoisomers in dairy products.
ABSTRACT
Objective To establish a gradient RP￣HPLC method for determining the related substances in lumefantrine. Methods The HPLC analysis was performed on an Agilent nucleosil 100￣5 C18(4.0 mm×125 mm,5 μm) column;the mobile phase was consisted of solution A,B and C,which included phosphate buffer solutions (consisting sodium hexane sulfonate,pH was adjusted to 2. 3 )￣water￣acetonitrile￣propanol with different proportion, with a gradient elution at the flow rate of 2.0 mL.min-1 , the detection wavelength was 265 nm, and the column temperature was 35 ℃ . Results An excellent separation achieved for lumefantrine from its related substances.Lumefantrine had a good linear relationship with the peak area within the range of 0.173 4-0.693 2 μg.mL-1(r= 0.999 6).The limit of determination was 0.06 μg.mL-1 . Conclusion The method is sensitive,reproducible and specific for the separation and determination of related substances in lumefantrine.