Determination of Chloramphenicol and Thiamphenicol Residues in Fish, Shrimp and Milk by ESI-LCMSMS

Chloramphenicol (CAP) and thiamphenicol (TAP) – analogue of CAP are widely used in the growth of animals and marine culture as they are broad spectrum antibiotics. Due to the development of resistance of microorganisms against antibiotics many countries have completely banned the use of them. A Negative Electro spray ionization mode with liquid chromatography and mass spectrometry was used to monitor the contamination of TAP and CAP in shrimp, fish and milk. Transitions 321 → 152, 120.4, 257 for CAP, 326 → 126, 157, 262 for CAP IS and 354 → 184.9, 168.8, 78.8 for TAP were monitored. For extraction of antibiotics ethyl acetate was used, showed recovery batter than 75% in all three matrixes. For timely efficient separation Agilent Eclipse C18 column was used with the simple isocratic mobile phase methanol as A (99%) and water: methanol in ratio of (8:2) as a B (1%), which needed 3.5 min to elute out both the compounds. Full validation was done as per EU decision 2002/657. Linearity was greater than 0.99. Coefficient variation was performed at 3 different concentrations and it was not greater than 3% between 6 replicates. CCα and CCβ in different matrices on an average were 0.27 and 0.29 μg/kg for CAP and 51.85 and 53.45 μg/kg for TAP. Accuracy was calculated at three different concentrations and the readings were found between 90 to 110%. Youden approach was used for the calculation of ruggedness and their statistically calculated results were satisfactory. Method was applied to the samples in which 56 shrimp, 18 fish and 8 milk samples were tested and 4 shrimp samples were found positive at MRPL level V.R. Vora & M.K. Raikwar 824 so that the method is fit for CAP and TAP analysis of commercial products at MRL compliance.