| The situation of antibiotics in agricultural application leads to their presence in animal original foods. The separation and analysis of aminoglycoside (alkaline, highly polarity) and macrolide (alkaline, hydrophobicity) antibiotics always encountered difficulties due to the peculiar physico-chemical properties, including the selectivity and recovery in sample preparation, and separation selectivity in hydrophilic interaction chromatography for aminoglycosides and tailing peak shapes for macrolides. This thesis investigates the high selective separation and high sensitive detection techniques of aminoglycoside and macrolide antiobics residues in foods.A weak cation exchange stationary phase named TGA was synthesized using the thiol-ene radical addition reaction, and a two dimensional solid-phase extraction (2D-SPE) method for the enrichment and cleanup of aminoglycosides was developed based on the TGA stationary phase. TGA and C18 materials were packed into an SPE cartridge in succession, with a sieve plate between them. Aminoglycosides were retained on the SPE cartridge first by ion-pair chromatography then by weak cation exchange chromatography. During the total process, aminoglycosides went through with twice enrichment at the head of the column, twice rinsing and twise elution process. Compared with traditional one dimensional solid-phase extractin (1D-SPE), the established 2D-SPE approach effectively improved the enrichment selectivity, recovery and matrix effect. The 2D-SPE method was successfully applied in the high sensitive detection of aminoglycosides in milk matrix.A highly selective separation method for aminoglycosides by hydrophilic interaction chromatography (HILIC) was developed based on a zwitterionic Click TE-Cys column. Chromatographic optimization revealed that aminoglycosides could be separated with high selectivity with high buffer concentration and low pH value in the mobile phase. The investigation of the basic equations for describing adsorptive and partitioning interaction revealed that adsorption mechanism dominated the retention of aminoglycosides, i.e. the direct interactions (e.g. hydrogen bonding, electrostatic interaction) is the main factor for the separation. At the optimized conditions,10 aminoglycosides were separation with high selectivity. Meanwhile, spectinomycin and its related impurities were effectively resolved. Besides, Click TE-Cys exhibited good separation selectivity for inorganic ions in HILIC mode, which could be used for the determination of counter-ions in the Pharmaceuticals with salified formulations.A high performance separation method for macrolide antibiotics was developed based on a positively charged C18HCE column. The electrostatic repulsion interaction between macrolides and C18HCE material improved the peak shape thereby the sensitivity in mass spectrometry detection. The calculation of gradient separation efficiency indicated that basic compounds with positively charged C18HCE column was highly sensitive with mobile phase conditions, thus gradient elution was necessary for the separation of basic compounds. Finally C18HCE was applied for the determination of 7 macrolide residues in honey matrix.A novel reversed phase/strong anion exchange mixed-mode stationary phase named C18SAX was synthesized based on the polar-copolymerzed approach. C18 ligand and quaternary ammonium ligand was simultaneously immobilized to the silica surface with a controllable ratio. Chromatographic evaluation indicated that the C18SAX stationary phase possessed typical hydrophobic and anion-exchange properties. A C18SAX based SPE method was developed with HPLC evaluation for the selective enrichment of aristolochic acids in Caulis Aristochiae Manshuriensis extract. Four aristolochic acids were purified with high purity. |
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