The occurrence of
tigecycline (TGC), a new first glycylcycline
antibiotic residues in food products harmfully influences potential
human consumers health. Therefore, analysts are forced to develop
new microextraction methods connected with modern extractants for
effective isolation of this compound. For this purpose, deep eutectic
solvents (DES) as the extraction media were used. Liquid–liquid
microextraction (LLME) of tigecycline from milk samples with application
of the hydrophobic deep eutectic solvents: decanoic acid:thymol (1:1),
thymol:camphor (2:1), dodecanoic acid:menthol (2:1), and dodecanoic
acid:dodecanol (1:1) was developed. The studied samples were subjected
to a deproteinization process using trichloroacetic acid solution
and acetonitrile. The optimal microextraction parameters, molar ratio
of DES components, amount of extraction solvents, pH of milk sample,
shaking, and centrifugation time, were chosen. Tigecycline in the
obtained microextracts of deep eutectic solvents was analyzed using
a liquid chromatographic technique connected with a tandem mass spectrometry
(LC-MS/MS) system. The limits of detection and quantification values
for TGC determination followed by DES-LLME-LC-MS/MS method were in
the 1.8 × 10–11 mol L–1 (0.01
μg kg–1) to 4.0 × 10–9 mol L–1 (2.28 μg kg–1)
and 5.5 × 10–11 mol L–1 (0.03
μg kg–1) to 1.2 × 10–8 mol L–1 (6.84 μg kg–1)
ranges, respectively. The RSD values of precision were in the range
1.4–7.8% (intraday) and 5.4–11.7% (interday). The developed
procedures were used for the determination of tigecycline in different
bovine milk samples.