Rapid determination of chloramphenicol residues in milk powder by liquid chromatography–elektrospray ionization tandem mass spectrometry

A simple and rapid liquid chromatography tandem mass spectrometry (LC–ESI–MS–MS) confirmation method for the analysis chloramphenicol (CAP) in milk powder has been developed. Samples were extracted by using liquid–iquid extraction steps with ethyl acetate. Lipids were removed using hexsan. LC separation was achieved by using a Phenomenex Luna C-18 column and acetonitryle–water as a mobile phase. The mass spectrometer was operated in multiple reaction monitoring mode (MRM) with negative electro-spray interface (ESI–). The four transitions were monitored m/z 321 → 257, 321 → 194, 321 → 152, 326 → 157 (IS) and for quantification, the transition m/z 321 → 152 was chosen. Validation of the method was done according to criteria of Decision Commission No 2002/657 EC. Validation includes the determination of specification, linearity, precision (within- and between-day), accuracy, decision limit (CCα) and detection capability (CCβ). Samples were fortified at CAP levels 0.30, 0.45 and 0.60 μg/kg with CAP-5d as internal standard. The precision within-day (RSD%) was lower than 12% and accuracy (RE%) ranged from −9.8 to −3.7%. The precision between-day (RSD%) was less than 15%. The limit of decision (CCα) and detection capability (CCβ) for milk powder 0.09 and 0.11μg/kg. Value CCα and CCβ were calculated for the 321 → 152 ion transition. This method has been successfully used for routine analysis.