Residue Monitoring And Removal Technology Of Metronidazole And Ofloxacin In Honey

This paper reports an analytical method for the determination of metronidazole,tinidazole,ornidazole,ofloxacin,ciprofloxacin and enrofloxacin in honey,and the best adsorption resin and the best adsorption condition were selected by physical adsorption method-macroporous adsorption resin to the 6 antibiotics in honey.The physicochemical indexes of honey in the honey were measured before and after the adsorption of macroporous adsorption resin,and the quality of honey was evaluated.The adsorption isotherm equation and thermodynamic parameters of the best macroporous resin were obtained by the adsorption isotherm and the Freundlich adsorption isotherm model.The adsorption effect and adsorption process of the macroporous resin on these 6 kinds of antibiotics were evaluated and explained.There are five chapters in this paper,and the main contents of the experiment are divided into the following four parts:1.This study uses QuEChERS pretreatment technology combined with LC-MS/MS,established a method for the simultaneous determination of metronidazole,tinidazole,ornidazole,ofloxacin,ciprofloxacin and enrofloxacin residues in honey.The standard curve obtained by Acacia and jujube matrix standard solution to eliminate matrix interference in honey,The linear correlation coefficient of 6 kinds of drugs of acacia and jujube in the standard solution matrix are greater than 0.990 and0.992,showed that in the range of 10.0~100.0ng/m L of the compounds showed a good linear relationship.The recovery rates of six kinds of drugs by the solution standard curve were 4.4% to 59.1% and 9.8% to 46.2% with relative standard deviations(RSDs)<5.2% and the recovery rates of six kinds of drugs by the matrix standard curve ranged from 82.0% to 117.8% and 79% to 115.9% with relative standard deviations(RSDs)<6.3% in acacia and jujube honey samples.The results show that the method is accurate and repeatable,and can be used for the detection of6 kinds of antibiotics in honey.2.The present study originally develops an environmental-friendly method for removing the nitroimidazoles and quinolones from honey by macroporous adsorption resins(MARs).The adsorption characteristics of nitroimidazoles and quinolones on five types of MARs(LSI-1,LSI-2,LSI-3,LS-901 and LS-902,)were evaluated.The adsorption conditions(proper resin,adsorption temperature,adsorption time and resin content)optimized by the static adsorption test.The results indicated that LSI-1 and LSI-2 resins exhibited better desorption capacities than other resins to nitroimidazoles and quinolones analyzed by LC–MS/MS.Combination of LSI-1 and LSI-2 resin in1:2 ratio highlighted the best desorption capacities on nitroimidazoles and quinolones,with removal rate reaching more than 92.48%,adsorption for 165 min at 25? and 26.6 g resin/kg honey.Under the optimal conditions,the LSI-1:LSI-2 resin(1:2)can be less than the maximum residue limit of the 6 antibiotics.3.The physical and chemical indexes of honey before and after adsorption of LSI-1:LSI-2 resin(1:2)were determined,and the total sugar,protein,proline and amylase values of honey were all somewhat decreased,but the range of decline was relatively small.the color value is somewhat increased,but the range is small.It shows that the macroporous adsorbents resin have little influence on the physical and chemical indexes,while removing nitroimidazole and quinolones.The contaminated honey treated with this way could be safely used as food sweetener or bioenergy.4.The adsorption behavior of honey of metronidazole,tinidazole and ornidazole,ofloxacin,ciprofloxacin and enrofloxacin in macroporous resin was carried out on the thermodynamic study.The results show that at three temperatures of 298.15 K,308.15 K and 318.15 K,the correlation coefficient of the Freundlich adsorption isotherm equation R2 is more than 0.93.It shows that the Freundlich fitting model can describe the adsorption process of the 6 antibiotics of LSI-1:LSI-2 resin(1:2)to the honey.The final calculated by LSI-1:LSI-2 resin(1:2)antibiotics adsorption enthalpy change ?H<0,shows that the heat released from the resin adsorption process,low temperature to adsorption;The adsorption process of the Gibbs free energy of ?G<0,indicating that the adsorption of the resin on the 6 kinds of antibiotics were spontaneous.