title: Determination of chloramphenicol in milk powder using liquid-liquid cartridge extraction (Chem Elut) and liquid chromatography-tandem mass spectrometry.
abstract: BACKGROUND
  The European Union prohibits the use of chloramphenicol (CAP) as a veterinary drug in food-producing animals. Nevertheless, CAP have been detected in milk products (liquid milk and milk powder). Therefore, it is necessary to develop sensitive methods for determining CAP residues in milk powder.
  
  
  OBJECTIVE
  The aim of this study was to develop and validate a confirmatory method for determination of CAP in milk powder.
  
  
  METHODS
  Chloramphenicol was determined in milk powder using LC-ESI-MS/MS in negative mode. After fat removing milk powder sample was extracted/cleaned-up with a Chem Elut extraction cartridge. Separation was achieved on a Phenomenex Luna C-18 column with acetonitrile-water as a mobile phase. The mass spectrometer was operated in multiple reaction monitoring mode (MRM). Four transitions were monitored m/z 321→152, 321→194, 321→257 (CAP) and 326→157 (IS CAP-d5).
  
  
  RESULTS
  Linearity, accuracy, precision, decision limit (CCa), detection capability (CCb) and ruggedness were determined for m/z 321→152. The mean relative recoveries (inter standard-corrected) of CAP from whole milk powder spiked at levels 0.1, 0.2, 0.3 and 0.6 mg/kg were in the range 95 - 103%. Relative standard deviation (RSD%) of recoveries at all spiked levels were less than 14%. RSDs within-laboratory reproducibility calculated at fortification of 0.3 mg/kg was less than 16%. CCa and CCb were below 0.1 mg/kg.
  
  
  CONCLUSIONS
  The developed LC-MS/MS method allows the determination of CAP in milk powder. The method was validated according to the Commission Decision No. 2002/657/EC requirements. This method can be applied to determination CAP in whole and skim milk powder.
authors.affiliation: Laboratory of Chemical Examination in Foodstuffs, Department of Hygiene Veterinary, Voivodeship Veterinary Inspectorate, Białystok, Poland.
authors.forename: Iwona
authors.initials: I
authors.lastname: Zawadzka
authors.forename: Lech
authors.initials: L
authors.lastname: Rodziewicz
mesh_terms: D000818:Animals; D002701:Chloramphenicol / Q000032:analysis*; D002853:Chromatography, Liquid / Q000379:methods; D005506:Food Contamination / Q000032:analysis*; D006801:Humans; D008892:Milk / Q000737:chemistry*; D011208:Powders; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods
chemical_list: D011208:Powders; D002701:Chloramphenicol