A method for the determination of sucralose in dairy products by high performance liquid chromatography (HPLC) was developed.Samples were deproteinized by adding lead acetate followed by cleanup on an Oasis HLB solid-phase extraction cartridge.The separation was performed on a C18 column with 15％ acetonitrile in water as the mobile phase,and the analyte was detected with an evaporative light-scattering detector (ELSD) detector.The recovery of sucralose at spiked concentration levels of 7.5-70 mg/kg was 94.6％-101.3％.The limit of quantitation at a signal-to-noise ratio of 10 was 7.5 mg/kg.This method proved to be accurate,simple and suitable for the analysis of sucralose in dairy products.

A method for detecting acesulfame-K, saccharin sodium, benzoic acid, sorbic acid, dehydroacetic acid, methyl vanillin and ethyl vanillin in dairy products by using high performance liquid chromatography (HPLC) is described. The sample was deproteinated and filtered, then separated on a C18 column with a mobile phase made up of methanol and ammonium acetate solution, and detected for absorbance at 230 nm. The seven substances were completely separated within 35 min. Their calibration curves were linear in the range of 1–100 mg/kg with correlation coefficients (R2) all above 0.999 0 under the selected conditions, and the recovery of the proposed method was 80.0% –105.7%. The method proved to be rapid, simple, and reliable.

A method for the determination of lactulose in milk powder by high performance liquid chromatography (HPLC) was developed. Lactulose was extracted with water. The analysis was performed on a NH2 column using 80% acetonitrile in water as the mobile phase. The recovery of lactulose spiked into milk powder in the range of 0.3–2.0 g/100 g was 97.4%– 103.0%. The limit of detection was 0.3 g/100 g. The results indicated that this method is accurate, simple and suitable for the analysis of lactulose in milk powder.

A method for the determination of nucleotides in milk powder by high performance liquid chromatography (HPLC) was developed. Nucleotides were extracted with water, deproteinated with 0.5% acetic acid and cleaned up by an SAX solid phase extraction (SPE) column. The analysis was performed on C18 column using 0.1 mol/L phosphate as the mobile phase. The recoveries of spiked samples at three levels ranging from 0.3 to 50 mg/100 g were higher than 90%. The limit of quantification was 0.3 mg/100 g. This method was accurate, simple, reproducible, and suitable for the analysis of nucleotides in milk powder.