Microextraction of Tigecycline Using Deep Eutectic Solvents and Its Determination in Milk by LC-MS/MS Method

The occurrence oftigecycline (TGC), a new first glycylcyclineantibiotic residues in food products harmfully influences potentialhuman consumers health. Therefore, analysts are forced to developnew microextraction methods connected with modern extractants foreffective isolation of this compound. For this purpose, deep eutecticsolvents (DES) as the extraction media were used. Liquid-liquidmicroextraction (LLME) of tigecycline from milk samples with applicationof the hydrophobic deep eutectic solvents: decanoic acid:thymol (1:1),thymol:camphor (2:1), dodecanoic acid:menthol (2:1), and dodecanoicacid:dodecanol (1:1) was developed. The studied samples were subjectedto a deproteinization process using trichloroacetic acid solutionand acetonitrile. The optimal microextraction parameters, molar ratioof DES components, amount of extraction solvents, pH of milk sample,shaking, and centrifugation time, were chosen. Tigecycline in theobtained microextracts of deep eutectic solvents was analyzed usinga liquid chromatographic technique connected with a tandem mass spectrometry(LC-MS/MS) system. The limits of detection and quantification valuesfor TGC determination followed by DES-LLME-LC-MS/MS method were inthe 1.8 x 10(-11) mol L-1 (0.01 & mu;g kg(-1)) to 4.0 x 10(-9) mol L-1 (2.28 & mu;g kg(-1))and 5.5 x 10(-11) mol L-1 (0.03 & mu;g kg(-1)) to 1.2 x 10(-8) mol L-1 (6.84 & mu;g kg(-1))ranges, respectively. The RSD values of precision were in the range1.4-7.8% (intraday) and 5.4-11.7% (interday). The developedprocedures were used for the determination of tigecycline in differentbovine milk samples.