| Erythromycin and lincomycin are usually used in the control of bee larvae diseases. However,some reasons, such as their ambiguous withdrawal period and the recycling of comb in the apicultureproduction process, led to that the phenomenon of erythromycin and lincomycin residual exceeding thestandards were usually found. Therefore, the research aims to develop a detection method forerythromycin and lincomycin residues in honey, comb and honeybee, to investigate the change rule ofthese drugs existing in their body after feeding them, and to explore their degradation rule in the processof honey processing and storage, so as to provide theoretical basis for beekeeping dosage, formulationof withdrawal time, selection of honey processing and storage conditions, and so on.This research mainly divided into three parts:In the first part, an effective high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS) method was developed for the validation and trace analysis of erythromycin andlincomycin residues in honey, comb and honeybee. Before using the high performance liquidchromatography-tandem mass spectrometry (HPLC-MS/MS) to determine the content of erythromycinand lincomycin, the author optimized the method of sample pretreatment and separation, what was thatthe erythromycin and lincomycin were extracted from samples (honey, comb and honeybee) with Trisand CaCl2mixed solution (pH=9.0), and clean-up with an Oasis HLB cartridge, so that the clean degreeof the sample solution conformed to the requirements of the mass spectrum. The method realizedrelevant parameters of HPLC and MS/MS optimum selection for determination of erythromycin andlincomycin. It turned out that erythromycin and lincomycin had good correlation coefficients when thelinear range was from0.5μg/kg to20μg/kg. The correlation coefficients of erythromycin andlincomycin were0.9905and0.9997respectively when the method detection limits was0.1μg/kg. Theaverage recovery and relative standard deviation both met the requirements of residual analysis afteradding erythromycin and lincomycin mixed standard solution to blank samples (honey, comb andhoneybee) at three concentration levels. The method is simple, accurate and sensitive for thesimultaneous determination of erythromycin and lincomycin.In the second part, the change rules of erythromycin and lincomycin injected in honey, comb andhoneybee and their difference were researched. The study results indicated that erythromycin andlincomycin reached the maximum concentration at the same time in comb and honeybee, which were inthe range between3d to8d and0d to3d days after feeding the drugs respectively, but in honey,lincomycin was faster to reach the maximum concentration than erythromycin., which were13d and23d after feeding the drugs respectively. The reason may be that lincomycin was more likely to dissolvein water and honey than erythromycin. Considering the limits of erythromycin and lincomycin (whichwere200μg/kg and100μg/kg respectively) injected in the edible animal tissues, the largest feed quantityof erythromycin was suggested to be10mg per full box bee, and the feed quantity of lincomycin shouldbe less than10mg per full box bee because of its stability and difficult decomposability. Meanwhile, the experimental result provided the theoretical basis for setting the withdrawal time of the erythromycinand lincomycin usage on swarm.In the third part, it mainly studied the degradation rule of erythromycin and lincomycin in honeyduring the different conditions of processing and storage. The study results indicated that erythromycinwas highly unstable and easy to degradation in the common mechanic temperature (50℃-70℃), whilelincomycin was stable at high temperature. In the storage experiments, it was found that erythromycinwas easily degraded in the storage process, while the concentration of lincomycin changed little. Thus,it will be degraded up to standard during processing and storage later even honey contains excessiveamounts of erythromycin. However, for lincomycin, it can only reduce its dosage in the process ofbeekeeping to control the content of lincomycin in honey. |
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