Introduction::
In the present study, a sensitive and selective liquid chromatography-tandem mass spectrometry
(LC-MS/MS) method was described for the determination of ceftiofur (CEF) in cow milk and pharmaceutical preparations.
CEF is an antibiotic compound, which is commonly used in the treatment of animal diseases such as respiratory system, soft
tissue, and foot infections, as well as postpartum acute puerperal metritis. One of the critical features of CEF is its prescription
while breastfeeding of cows; in accordance, its quantitative estimation is essential to assess its residual amounts.
Methods::
In the method reported herein, after simple protein precipitation using acetonitrile, the pre-treated samples were
introduced in to an LC-MS/MS instrument equipped with a Chromolith® High-Resolution RP-18 series HPLC column (100
mm × 4.6 mm from Merck KGaA, Germany). Electrospray ionization was employed as the ionization source in the triplequadrupole
tandem mass spectrometer.
Results::
For the calibration method using solvent-based standards; LOQ was 3.038 ng/mL, 12.15 ng/mL, and LOD was
1.215 ng/mL and 6.076 ng/mL for ESI+ and ESI- modes, respectively. On the other hand, for the method of matrix-matched
standards; LOQ was 1.701 ng/mL, 10.13 ng/mL, and LOD was 0.486 ng/mL and 5.929 ng/mL for ESI+ and ESI- modes, respectively
as obtained from signal to noise ratio.
Conclusion::
Applicability of both positive and negative ion modes was tested, and the analyte was detected via multiple reaction
monitoring. The distorting effects of the milk matrix on the MS ionization and quantitation of CEF were overcome by
using matrix-matched calibration for the first time.
