A quantitative multi-class analytical method covering more than 226 veterinary drugs and other contaminants in muscle, belonging to different drug families, was developed. The method is based on liquid-liquid extraction, purification by low-temperature clean-up and dispersive solid-phase extraction (D-SPE), and analysis was conducted in two analytical runs by column-switching UPLC coupled with electrospray ionisation and tandem mass spectrometry (UPLC-ESI-MS/MS). For most of the target analytes, the optimised pre-treatment processes led to no significant interference from the sample matrix. The limit of quantification varied from 0.05 to 10 µg kg(-1). Statistical evaluation indicated that average recoveries spiked into pork were in the range from 62.4% to 138.8%, and the relative standard deviations were in the range from 2.8% to 26.6% (intra-day precision). The availability of this method will contribute to a better safety assurance of meat with a significant reduction of both effort and time.

^Äëíê~Åí= High-value dairy proteins such as lactoferrin (LF) and immunoglobulin (IgG) were separated from bovine colostrum. The whey was initially adjusted to pH 6.8 with 1 mol/L NaOH and then went through centrifugation, precipitation, and filtration to eliminate the fat and caseins in bovine colostrum. The treated whey was further ultra-filtrated to partially remove both other proteins and carbohydrates under 50 kD molecular weight. Then the ultra-filtrated whey was passed through cation and anion exchange columns in series. The LF and IgG were adsorbed on cation and anion exchanger, respectively, due to their different pI. Both the cation and anion exchange columns were washed with de-ionized water followed by successive elution with sodium chloride solutions of increasing molarities (0.27 and 0.85 mol/L; 17 and 51 mmol/L) in a stepwise manner, respectively. After desalted, the elution was freeze-dried. Finally, the LF and IgG with respective purities of 95.0% and 96.6% were obtained. © KSBB hÉóïçêÇëW=ÄçîáåÉ=ÅçäçëíêìãI=ä~ÅíçÑÉêêáå=EicFI=áããìåçÖäçÄìäáå=d=EfÖdFI=éìêáÑáÅ~íáçåI=áçå=ÉñÅÜ~åÖÉ=ÅÜêçã~íçÖê~éÜó=