Development Of Analytical Method Of Neomycin Residue In Water Samples And Its Application On The Analysis Of Animal Products

Neomycin is a broad spectrum, efficiently bactericidal aminoglycoside antibiotic, which is widely used in the treatment of bacterial infections and animal diseases. The use of neomycin on a large scale as a therapeutic agent gives rise to drug residues in edible products of animals, which can adversely affect the public health and environmental safety. Therefore, residue analysis plays an important role in the food safety monitoring and management. In this dissertation, the method of high performance anion exchange chromatography (HPAE) coupled with pulsed amperometric detection (PAD) had been developed and applied to the determination of neomycin in water, milk and serum samples. The detail information is as follows:1) Establishment of analytical method for neomycin in water samplesA simple, fast and reliable method using high performance anion chromatography with pulsed amperometric detection had been developed for the analysis of neomycin in water samples. The influence of concentration and pH of the mobile phase on the separation and detection was investigated. The elution and separation were carried out with an isocratic mobile phase containing 10 mmol/L NaOH. A quadruple-potential waveform used for the detection was optimized. The detection limit of neomycin was down to 27 ng/mL. The linearity of neomycin calibration curve ranged from 50.0 to 505 ng/mL with correlation coefficient of 0.9997. The relative standard deviation (RSD) for neomycin determination was 4.0% (n=11). This method which avoids formation of ion-pair compounds in RP-HPLC and derivatization procedure in the detection, is quick, high sensitive and reproducible.Using the proposed method, neomycin concentration in several water samples spiked with neomycin and a neomycin sulfate ear drop were determined. The recoveries of neomycin at a concentration of 50.0 ng/mL in spiked water samples were approximately 70.0%.2) Application of analytical method on the determination of neomycin residue in milkMilk was deproteinated with trichloroacetic acid, and then cleaned up with a weak cation-exchange cartridge. Neomycin residue in milk was also analyzed using HPAE-PAD. The influence of various parameters on clean-up of neomycin in milk, including the concentration of trichloroacetic acid, centrifugation speed, the flow rate and the concentration of eluent, were investigated. The average recoveries of neomycin in milk ranged from 50.3% to 76.9%. The linear calibration curve ranged from 10.0 to 80.0 ng/mL with correlation coefficient of 0.9993. The proposed method is simple, reliable, organic solvent free and especially suitable for analysis of low-level neomycin residue in milk.3) Application of analytical method on the determination of neomycin residue in serumThe similar method with deproteination using trichloroacetic acid, and clean-up using a weak cation-exchange cartridge was applied to sample pretreatment of serum. Neomycin residue in serum was detected with HPAE-PAD. The influence of pH on retention of neomycin in the cartridge was investigated and washing procedure of solid-phase extraction was optimized. The average recoveries of neomycin in serum ranged from 53.9% to 80.6%, with RSD below 10.0%. The linear calibration curve ranged from 50.5 to 505 ng/mL with correlation coefficient of 0.9951.A chicken-breeding experiment was carried on by feeding neomycin sulfate to chicken for 14 days. Neomycin residues in chicken serum were studied in different periods of breeding. The results show that neomycin concentration in serum on the first day after feeding is 179.9±14.6 ng/mL (n=3,RSD=8.1%) and on the third day neomycin residue can not be quantified. Five days later, neomycin concentration is lower than the detection limit.