Abstract

Determination of chloramphenicol residues in milk powder by mass spectrometric method

Author(s): Shiva Kant Dwivedi, D.D.Agrawal

Chloramphenicol (CAP) is no longer a first-line agent for any indication because of resistance and safety concerns; it has been banned in several countries, including the European Union (EU), for treatment of food-producing animals. But CAP is still illegally used in animal farming because of its easy access and low cost. Therefore, effective detection techniques are required for a strict control of this compounds entry in food chain. So aimof the present study was to optimize and validate the analytical parameters for analysis of chloramphenicol residues by liquid chromatography tandem mass spectrometry (LC-ESI-MS-MS) in milk powder. Sample preparation performed by extraction of milk samples with ethyl acetate and evaporated to dryness, followed by a clean-up step using the liquid liquid extraction with isooctane. Multiple reactions monitoring (MRM) acquisition method in negative ionization mode with the transitions of m/z 320.54-151.94, 320.54-256.9, 325.7-157.1 (IS) used. For the quantification transitionm/z 320.54-151.94was chosen bymatrix-matched calibration curves, ranging from0.15 to 0.75 ìg kg-1, with regression coefficients of 0.99. The recovery, repeatability, reproducibility and CCalpha and CCbeta were evaluated. The limit of decision (CCá) and detection capability (CCâ) for milk powder was 0.085 and 0.109 ìg kg-1. The repeatability (RSD%) was lower than 12.5 % and reproducibility (RSD %) was less than 12.43 %. On the basis of these analytical parameters and performances we have placed optimization step in a method as a monitoring tool for unacceptable levels of residues of CAP inmilk powder.