Multiresidue automated turbulent flow online LC-MS/MS method for the determination of antibiotics in milk

Bousova, Katerina
Senyuva, Hamide
Mittendorf, Klaus
A fast and reliable multiresidue method is reported for the identification and quantification of 36 different compounds from seven different classes of antibiotics (aminoglycosides, sulfonamides, macrolides, quinolones, tetracyclines, lincosamides and trimethoprim) in milk. Automated online sample cleanup was applied using turbulent flow chromatography (Transcend TLX system), directly coupled to a mass spectrometer (MS/MS) for sensitive and specific detection. The method involved a simple extraction/protein precipitation using acetonitrile, followed by centrifugation and filtration. After this preliminary step, the extract was injected into the TLX-ESI-MS/MS using optimised turbulent flow and liquid chromatography (LC) conditions. Single-laboratory validation of the method was carried out according to the Directive 2002/657/EC, clearly demonstrating the suitability of this method for quantitative determination of this wide range of antibiotics in milk. A small survey, which covered milk samples of different origin and varied fat content, demonstrated the robustness of this method and its suitability for enforcement purposes.


Medium optimization for cephamycin c overproduction and comparison of antibiotic production by ask, hom, and ask+hom recombinants of streptomyces clavuligerus
Ünsaldı, Eser; Özcengiz, Gülay; Department of Biology (2010)
Streptomyces clavuligerus is well-known for synthesizing several β-lactam antibiotics like cephamycin C which is produced through aspartic acid pathway initiated by aspartokinase (Ask) enzyme encoded by ask. Four different strains were constructed in our laboratory to increase cephamycin C production by S. clavuligerus. TB3585 and BA39 contained extra copies of ask gene on a multicopy plasmid, control strains TBV and BAV contained vector only in wild type strain NRRL3585 and hom-minus background, AK39, resp...
Reinvestigation of the synthetic and mechanistic aspects of Mn(III) acetate mediated oxidation of enones
Demir, Ayhan Sıtkı; Reis, O; Igdir, AC (Elsevier BV, 2004-04-05)
Mn(OAc)(3) mediated alpha'-acetoxylation of alpha,beta-unsaturated enones is reinvestigated from a synthetic and mechanistic point of view and an improved procedure based on the use of acetic acid as a co-solvent is presented. Excellent results were obtained for a variety of structurally diverse and synthetically important enones under the optimized conditions.
Asymmetric aldol addition of alpha-azido ketones to ethyl pyruvate mediated by a cinchona-based bifunctional urea catalyst
Okumus, Seda; Tanyeli, Cihangir; Demir, Ayhan Sıtkı (Elsevier BV, 2014-07-30)
The first asymmetric synthesis of ethyl 4-aryl-3-azido-2-hydroxy-2-methyl-4-oxobutanoates via a cinchona organocatalyst induced aldol addition of alpha-azido ketones to ethyl pyruvate has been developed. The coupling reaction under optimized conditions was carried out to furnish tetrafunctionalized synthons with enantioselectivities of up to 91:9 and enriched diastereoselectivities of up to 95:5 (syn:anti).
Folic acid functionalized PEG coated magnetic nanoparticles for targeting anti-cancer drug delivery: Preparation, characterization and cytotoxicity on Doxorubicin, Zoledronic acid and Paclitaxel resistant MCF-7 breast cancer cell lines
Keskin, Tugba; Yalcin, Serap; Gündüz, Ufuk (2018-01-01)
In this study, MNPs were synthesized, coated with biocompatible polyethylene glycol (PEG) and conjugated with folic acid. Crystal and chemical structures, shape, size and magnetic properties of synthesized nanoparticles were characterized. Agglomeration tendency of naked nanoparticles were prevented by oleic acid addition during the synthesis. All synthesized MNPs have been found to exhibit superparamagnetic behavior at 23 degrees C and 37 degrees C. Cytotoxic effects of MNPs were investigated on Doxorubici...
Quantitative expression analysis of the genes potentially involved in clavulanic acid overproduction in streptomyces clavuligerus
Aktaş, Caner; Özcengiz, Gülay; Department of Molecular Biology and Genetics (2018)
Streptomyces clavuligerus is the producer of the medically important β-lactam antibiotics, including cephamycin C (CC) and the potent β-lactamase inhibitor clavulanic acid. (CA). We have already undertaken an extensive comparative proteomic analysis by using both 2-DE-MALDI-MS and GeLC-MS approaches between an industrial CA overproducer, namely DEPA and the reference strain NRRL3585. In this context, we documented several differentially expressed (over- and under-represented) proteins accounting for high CA...
Citation Formats
K. Bousova, H. Senyuva, and K. Mittendorf, “Multiresidue automated turbulent flow online LC-MS/MS method for the determination of antibiotics in milk,” FOOD ADDITIVES AND CONTAMINANTS PART A-CHEMISTRY ANALYSIS CONTROL EXPOSURE & RISK ASSESSMENT, pp. 1901–1912, 2012, Accessed: 00, 2020. [Online]. Available: