Detection Of Veterinary Drug Residues In Dairy Products By Nuclear Magnetic Resonance

The safety of dairy products has been a hot topic in the society,as an important part of dairy products,the quality and safety of milk powder is also concerned.In this paper,qualitative and quantitative analysis of veterinary drug residues in dairy products was carried out to establish a suitable analysis method.The research will provide technical support for the detection of veterinary drug residue in dairy products,so as to ensure people’s food safety.First of all,47 kinds of common veterinary drug residues in dairy products were selected as research objectives.According to their structural characteristics,hydrogen spectrum,carbon spectrum,DEPT135°spectrum,¹H-¹H COSY,HSQC and HMBC were collected respectively,and the chemical shift assignment and coupling constant calculation of the spectral peaks were carried out,and the spectra were edited,summarized and summarized.Secondly,the milk powder was used as the matrix,and the mixed standard solution of Thiamphenicol and Albendazole was added to the matrix.After sample pretreatment,the samples to be tested were obtained,and the quantitative nuclear magnetic resonance method was established for quantitative analysis.The recoveries of Thiamphenicol and Albendazole were 90-120%and the relative standard deviation was less than 10%.The detection limits of Thiamphenicol and Albendazole were 1.10 mg/g and 1.39 mg/g,respectively.Then,Thiamphenicol and Sulfadiazine were qualitatively and quantitatively studied.Four major spectra（IR,UV-Vis,MS,NMR）were used to identify the main component of the sample as the target compound.By optimizing the deuterated reagent and experimental parameters,a quantitative nuclear magnetic resonance method was established to analyze the deuterium.The experimental conditions of Thiamphenicol were as follows:DMSO-d₆ as deuterium reagent,Ethylparaben as internal standard,(2 15 ppm,15.92 ppm,1 7 s,32 times,16 times.The result of quantitative nuclear magnetism is 97.58%,and the uncertainty is 0.28%.The mass balance method was established and the main component content was 98.84%,the inorganic element content was 1.41%.The legal value of mass balance is 97.45%,and the uncertainty is 0.24%.The final uncertainty of Thiamphenicol was 0.37%,and the two methods were consistent.At the same time,methodological verification was performed,and linearity（correlation coefficient R²greater than 0.99）,precision,repeatability,and stability（relative standard deviations were all less than 0.5%）were evaluated.Optimization of experimental conditions,the establishment of quantitative nuclear magnetic resonance method for the determination of Sulfadiazine,the fixed value of96.55%,the uncertainty of 0.26%.The result of mass balance method was 96.59%,and the uncertainty was 0.093%.The uncertainty of Sulfadiazine was 0.30%,and the results of two methods were consistent.