A method for determining vitamin C (VC) in dairy products by high performance liquid chromatography (HPLC) is described. Samples were added with metaphosphoric acid to precipitate proteins, filtered through filter paper, separated on a C18 chromatographic column with 0.25% metaphosphoric acid solution as mobile phase, detected with a UV detector, and quantified by an external standard method. The method proved simple and rapid with good accuracy and precision. The recovery of VC ranged between 93.6 % and 103.9% with relative standard deviation of 2.56% to 4.05%. The detection limit was 1 mg/kg.

A method for the determination of vomitoxin in milk powder by high performance liquid chromatography (HPLC) was developed. Samples were precipitated and filtered, and the supernatant was then purified and concentrated by immunoaffinity column chromatography, separated by C18 column chromatography, detected by ultraviolet detector and quantified by calibration curve method. The method proved to have good accuracy and precision. The spiked recovery of vomitoxin in dairy products was 98%–106%, and the relative standard deviations were 0.45%–1.21%. The detection limit of vomitoxin was 0.05 mg/kg.

A method for determining lutein in dairy products by HPLC is described. Samples were extracted with acetone and separated with a mobile phase made up of methanol and methyltert-butyl ether. The analysis was performed by UV detection at 445 nm, and the external standard method was used for quantification. This method has good accuracy and precision. The spiked recoveries in milk and milk powder ranged from 86.9% to 101.2% with a relative standard deviation of 2.56% to 4.05%. The detection limit was 0.02 mg/kg, and a linear range of 0.02 to 4 mg/kg was obtained.

A method for the determination of phosphatidylserine in milk powder by High performance liquid chromatography with evaporative light scattering detection（HPLC-ELSD）was developed. Samples were extracted with a mixture of chloroform and methanol. Chromatographic separation was performed on a Diol column by gradient elution using a binary mobile phase system consisting of hexane- isopropanol-acetic acid triethylamine and isopropanol-water-acetic acid-triethylamine. The recoveries of phosphatidylserine in milk powder at spiked levels between 50 and 150 mg/100 g were greater than 85%, and the limit of quantification was 30 mg/100 g. The proposed method has the advantages of accuracy,