In this paper we review recent applications of high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), ultra high performance liquid chromatography coupled with high-resolution time-of-flight mass spectrometry (HRTOF-MS), and matrix assisted laser desorption ionization-Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FTMS) to determine penicillin residues in milk and dairy products and their major enzymatic metabolites in vivo. This review describes recent progress in the development of sample extraction, purification, chromatographic separation and mass spectrometry detection methods for the determination of penicillin residues in dairy products.

This report describes an ion chromatography method for determining thiocyanate in dairy products. Milk samples were deproteinized by adding acetonitrile followed by centrifugation, microporous filtration and chromatography on LC-C18 SPE column. The analyte was monitored by ion chromatography. The optimized mobile phase consisted of 1.7 mmol/L sodium bicarbonate, 1.8 mmol/L sodium carbonate and 10% aqueous acetone solution. The suppressor was activated and regenerated with 0.2% sulfuric acid as an inhibitor. The detection limit for thiocyanate was 2.0 mg/kg, and the standard curve exhibited a correlation coefficient above 0.99 in the linear range of 0.1–20 mg/kg (mg/L). Recovery rates for spiked samples ranged from 93% to 97%, and repeatability expressed as relative standard deviation varied between 0.8% and 1.34% (n = 5). The detection accuracy for milk powder standard was 98%. The presented method was characteristic of easy operation, accurate and repeatable results and low detection limit, and was useful for the determination of thiocyanate in dairy products.

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,

This paper is about the detection the four serotypes A, B, E and F of Clostridium botulinum from milk powder and whey powder by using real-time fluorescent quantitative PCR method (RT-PCR). The standard curves for blends of serotypes A and B as well as of E and F were established using the original positive control from a commercial RT-PCR kit and its 10, 102, 103 and 104-fold dilutions. The cycle threshold (Ct) values exhibited excellent specificity, repeatability and accuracy. By using the method, none of these four serotypes was detected in 82 samples milk power and whey power with suspected strains as confirmed by the Chinese national standard and the industry standard of entry-exit inspection and quarantine.

A gas chromatographic (GC) method was developed and applied to determine conjugated linoleic acid (CLA) in milk and milk powder. Fat extraction from samples and methylation were made before GC analysis. Excellent separation of c9,t11-CLA was achieved. The developed method proved to be simple, safe, accurate, reliable and reproducible.