ABSTRACT
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.
Subject(s)
Deep Eutectic Solvents , Liquid Phase Microextraction , Humans , Animals , Chromatography, Liquid , Tigecycline , Milk/chemistry , Tandem Mass Spectrometry , Thymol/chemistry , Solvents/chemistry , Chromatography, High Pressure Liquid/methods , Liquid Phase Microextraction/methods , Limit of DetectionABSTRACT
A new extraction method was developed for isolation of the antihistaminic drugs (histamine H2 receptor antagonists) famotidine (FMT) and nizatidine (NZT) from aqueous samples. A low solvent consumption method using dispersive liquid-liquid microextraction (DLLME) was applied for this purpose. The parameters of the isolation, namely, volume of extraction and disperser solvents, pH of sample and shaking time were optimized. The influence of foreign substances on the extraction process was also studied. After separation of FMT and NZT using DLLME, the analytes in organic extracts were determinated by high-performance liquid chromatography combined with UV spectrophotometry and liquid chromatography connected with tandem mass spectrometry (LC-MS-MS). The use of DLLME for selective isolation of analytes enables their preconcentration. Enrichment factors 23 and 61 were obtained for FMT and NZT, respectively. These procedures enable detection of the analytes in real samples at levels 0.24 µg mL-1 (limits of detection (LOD) of FMT: 7.2·10-7 mol L-1 and LOD of NZT: 7.3·10-7 mol L-1). The method was applied for the determination of the studied antihistaminic drugs in river water and wastewater samples. The use of LC-MS-MS in conjunction with DLLME enabled detection of FMT in Netta river at a concentration level of 0.46 ± 0.04 ng mL-1.
ABSTRACT
Micellar extraction was applied to isolate famotidine from aqueous samples. This drug is an H2 receptor antagonist used for the treatment of stomach diseases. The process was performed with a mixture of anionic sodium dodecylsulfate and nonionic Triton X-114 surfactants. The effect of different parameters on the efficiency of the micellar extraction such as electrolyte and surfactant concentration, pH of sample, temperature, shaking and centrifugation time was investigated. The influence of foreign substances on a studied process was tested. The elaborated procedure was applied for HPLC-UV determination of famotidine in natural water samples. The calibration graph was recorded in the range 1.35-37.12 µg mL-1 of the studied compound. The repeatability of the method was equal to 7.4%. The limit of detection and quantification values for the determination of famotidine by using the proposed method amounted to 0.40 and 1.25 µg mL-1, respectively.
