Development Of HPLC Methods For Determination Of Nitroimidazoles Residues In Bee Products And Chicken Edible Tissues

Nitroimidazoles are a class of drugs for the treatment of anaerobic protozoan and bacterial infection. They are considered to be carcinogenicity and maximum residue limit in any animal edible tissue is zero. In order to determinate of nitroimidazoles residues in animals edible tissues, reverse phase high-performance liquid chromatographic methods (RP-HPLC) to detection of nitroimidazoles residues in bee product and chicken edible tissues by external standard was developed.Hydroxy-dimetridazole (DMZOH) is a major metabolite of dimetridazole (DMZ) in animal body. In order to find out the metabolic rule of dimetridazole and hydroxy -dimetridazole, a high-performance liquid chromatographic method for detection of DMZ and DMZOH residues in chicken edible tissues was developed. After an initial extraction with dichloromethane and subsequent evaporation, the samples were resolved in water. Hexane was used in the liquid-liquid extraction to removed fat. A C₁₈ solid-phase extraction was performed and the cartridge was eluted with methanol. Detecting wavelength was set at 320nm and the mobile phase was distilled water and methanol(86:14,v/v). The limit of detection and quantitation of this two drugs were both 1.0μg/kg. The control samples are all fortified with DMZ, DMZOH at levels of 1μg/kg, 2μg/kg, and 4μg/kg. The mean recoveries of DMZ respectively range from 56.9%to 76.5%in chicken muscle; respectively 63.3% to 72.6 %in chicken liver; respectively 63.5%to 75.7%in chicken fat. The inter-day relative deviation is less than 16% and the intra-day relative standard deviation is less than 15%. The method was applied to laying hens given feed containing 0.025% dimetridazole for 5 days. Residues of dimetridazole and its metabolite can't be detected in chicken edible tissues after 14 days.In this dissertation a method was developed for determination of metronidazole,ronidazole, dimetridazole, tinidazole and ornidazole in honey and royal jelly by high-performance liquid chromatography. The sample was diluted in hydrochloric acid, and royal jelly added sodium chloride and hexane in addition. Hexane was used to remove fat. Then Potassium phosphate dibasic was added to the diluted hydrochloric acid,and extracted with dichloromethane. The extracts were back-extracted with hydrochloric acid. A SCX solid-phase extraction was performed and the cartridge was eluted with potassium phosphate dibasic buffer solution (0.5moL/L, pH8.8). The eluted solution was solvated in dichloromethane, evaporated to dryness, then resolved in 0.5mL mobile phase. Detecting wavelength was 320nm and the mobile phase was water and acetonitrile (90:10, v/v). The limit of detection was 1.0 ng/g and the recovery of nitroimidazoles ranged from 59.2%to70.6%in honey respectively and 54.9%to 69.1% in royal respectively. The inter-day relative deviation is less than 18% and the intra-day relative deviation is less than 16%.The results showed that this two methods are accurate and feasible enough to determinate the nitroimidazoles residues and can be applied to determinate nitroimidazoles residues in bee product and chicken edible tissues.