Study On Fast Analysis Of Antibiotic Residues In Food And Environmental Samples

Antibiotics process strong antibacterial and anti-virus effect, and have been widely used to treat and prevent various diseases in humans and animals. However, the use of these antibiotics may be left in food of animal origin. Long-term consumption of food containing antibiotic residues will harm to people’s health. Moreover, significant amounts of antibiotics used in human and veterinary medicine are excreted and arrive in the environment, such as water and soil. Therefore the development of accurate, rapid and sensitive method for the determination of residues in food and environmental samples is necessary.In this paper we developed the methods for fast analysis of antibiotic residues in food and environmental samples. The main contents are as follows:1. The MMIP has been prepared using ciprofloxacin as template molecule, methacrylic acid as functional monomer, ethylene glycol dimethacrylate as crosslinking agent and Fe3O4 magnetite as magnetic component. The polymer has been used for extraction and separation of fluoroquinolones(FQs) including ciprofloxacin, enrofloxacin, lomefloxacin, levofloxacin,fleroxacin and sparfloxacin from environmental water samples. The polymer has been characterized by scanning electron microscopy, Fourier-transform infrared spectrometry and vibrating sample magnetometry. The Scatchard analysis method was used for evaluating the adsorption of polymer for template molecular. The optimal extraction conditions were as followed: 100 mg polymer was used for extracting 500 m L water sample, the extraction time was 7min, 6m L acetonitrile(3.0m L each time and washed two times) was used as washing solvent, and 3m L methanol–acetic acid(95:5, v/v)(1.0m L each time, desorbed three times, and ultrasound for 30 s during each desorption process) was used as desorption solution. The apparent concentration factor of 500 can be achieved, which was based on drying 3m L extract with a stream of nitrogen and dissolving in 1.0m L solution. The analytes were detected by liquid chromatography-tandem mass spectrometry. Under the optimal conditions, the linearity of the method obtained is in the range of 20~2000ng/L. The detection limits of FQs are in the range of 3.2 ~ 6.2ng/L. The intra- and inter-day relative standard deviations(RSDs) areranging from 2.5% to 7.2% and from 3.6% to 9.1%,respectively. The recoveries of FQs in three spiked levels(20, 100 and 200ng/L) are the range of 76%~94%. The proposed method was successfully applied to determine FQs in different water samples, such as lake water, river water, primary and final sewage effluent of hospital. Ciprofloxacin and fleroxacin were found in primary and final sewage effluent samples with the contents in the range of 26~87ng/L.2. An automated system based on the on-line coupling of SPE with HPLC was developed for the determination of TCs, such as tetracycline, oxytetracycline, chlortetracycline,metacycline and doxycycline in honey. When the sample solution passed through the SPE column, the target analytes are retained on the sorbent, wherever the waste discharged. Then the analytes were desorbed for the SPE sorbent by mobile phase introduced into chromatographic column for separation and detection. In the on-line operation, all analytes concentrated by SPE were directly introduced into the HPLC, and greatly improved the extraction efficiency. Chromatographic conditions were optimized. Five TCs were separated in less than 10 min with a gradient elution using a mixture of acetonitrile and 0.8% formic acid aqueous solution. The optimal extraction conditions were as followed: C18 was used as sorbent,Na2EDTA–Mc Ilvaine buffer(p H=4.0) was used as the condition solvent, and loading and washing time were 3 min. Under the optimal conditions, the linearity of the method obtained is in the range of 50~1000ng/g. The detection limits of TCs are in the range of 5~12ng/g. The RSDs of intra- and inter-day tests are ranging from 3.4% to 7.1% and from 3.2% to 8.9%. The recoveries of TCs with three spiked levels(80, 250 and 800ng/g) are in the range of 84±6%~121±4%. The risks of analytes loss and organic solvent volatilization are decreased as the overall analysis procedure takes place in a closed system. Moreover, this method saved analysis time and decreased the analysis errors.