Vol. 12, Issue 2 (2023)

Author(s):
S Kalpana, CH Umamaheswara Rao and M Muthukumar

Abstract:
A sensitive liquid chromatography–tandem mass spectrometric method has been optimized for determination of residual 3-amino-5-morpholinomethyl-2-oxazolidinone (AMOZ) in dried meat powder. Dried meat powder were extracted by acid hydrolysis followed by derivatization with 2-nitrobenzaldehyde, aliquot was evaporated to dryness and reconstituted in mobile phase.LC separation was carried out on a BEH C18 column (100 mm × 2.1 mm, 1.7 µm) column with gradient elution mode using mobile phase consisting of methanol and 2 mM ammonium format. LC-MS/MS analysis was done in multiple reaction monitoring (MRM) mode through an ESI interface operated in positive ionisation mode, with deuterated AMOZ-D5 as internal standard. Four identification points were obtained for AMOZ with one precursor ion and two product ions. Identification and quantification of the AMOZ were performed based upon the intensities of mass fragments from the precursor ions, MRM of NP-AMOZ: 335 > 291, 335 > 127; MRM of NP-AMOZ-D5 – 340.1 > 101.9, respectively. Linear matrix-matched calibration curves were obtained (regression coefficient ≥ 0.99) over the quantitation range of 0.1-5 µg/Kg with the limit of quantitation (LOQ) being 0.13 μg/Kg. Mean recoveries ranged from 81% to 108%, with the corresponding intra-day variation ranging from 2.7% to 6.6%, based on the spike concentration around MRPL. The proposed tandem mass spectrometric method is quite adequate for analysis of residual AMOZ in dried meat powder at and below EU MRPL (0.5 µg/Kg).