A method for the determination of fructose,glucose,sucrose,maltose and lactose in fermented milk drink by high performance liquid chromatography (HPLC) with refractive index detector was developed.The samples were extracted with water.The method was performed on a carbonhydrate column using acetonitdle-water as mobile phase.The average spiked recoveries of fructose,glucose,sucrose,maltose and lactose spiked in the concentration range of 0.2％-10.0％ were between 92.6％ and 102.0％ with relative standard deviation (RSD,n =6) less than 3.00％.The limit of quantitation was 0.2％.The results indicated that this method is accurate,simple,reproducible and suitable for the analysis of fructose,glucose,sucrose,maltose and lactose in fermented milk drink.

An analytical method to determine lactulose in ultra high temperature (UHT) sterilized milk by liquid chromatographic separation,evaporative light-scattering detection and external standard quantitation is described in this paper.After the protein was precipitated by adding hydrochloric acid,the separation was performed with satisfactory results on a NH2 column using 75％ acetonitrile in water as the mobile phase.The precision expressed as relative standard deviation (n =6) was 0.77％,and the average recovery was in the range of 98.7％-102.6％.This method was simpler and less time consuming with good repeatability than traditional enzymatic hydrolysis method.It can provide an alternative way of determining lactulose in UHT sterilized milk.

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 the determination of abamectin residues in dairy products and feed by using high performance liquid chromatography (HPLC) with fluorescence detection after precolumn derivation with trifluoroacetic anhydride and N-methyl imidazole was developed.Abamectin residues were extracted with acetonitrile,cleaned up on a tC18 solid phase extraction cartridge.After precolumn derivatization,the separation was performed on C18 column by gradient elution with methano-acetonitrile-water as mobile phase.The analyte were detected with a fluorescence detector and quantified by an external standard method.The recovery of abamectins spiked into milk powder at 1.5 μg/1 000 g (or 1 000 mL for milk) was higher than 90％.The limit of quantitation was 2 μg/kg for dairy products and 10.0 μg/kg for feed.This method proved to be accurate,simple reproducible,and suitable for the analysis of abamectin residues in dairy products and feed.

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 detecting thiocyanate in dairy products by high-performance liquid chromatography (HPLC) is described. The proteins in the samples were precipitated by the addition of acetonitrile, then the filtrate was separated on a strong anion exchange (SAX) column using a mobile phase made up of a mixture of sodium dihydrogen phosphate solution and methanol. The target compound was detected with a UV detector at 218 nm. The results showed that the calibration curve displayed a good linear relationship in the range of 0.2–100 mg/kg. The recovery rate of thiocyanate was 98.5%– 113.0%.The method is simple with good accuracy and stability for detecting thiocyanate in dairy products.

A method for the determination of fructooligosaccharides in modified milk by high performance liquid chromatography (HPLC) was developed. Fructooligosaccharides were extracted with water. The analysis was performed on a NH2 column using 70% acetonitrile in water as the mobile phase. The recoveries of fructooligosaccharides at four spiked levels between 20 and 500 mg/100 g ranged from 80.2% to 107.1%. The limit of quantification was 20 mg/100 g. This method is accurate, simple and suitable for the analysis of fructooligosaccharides in modified milk.