The Study On The Analysis Of DNA Fragment And The Measurement Standards Of Nucleotide

DNA fragment is a very important reagent for some new technologies such as genetic diagnosis, genotyping and DNA fingerprinting, which shows the universality and necessity of its application and its strict metrological characteristics. Currently, DNA fragment lengths and molecular weight standards are mainly purchased from biotech companies. DNA fragment from the biotech company are very expensive and also can’t guarantee the quality and traceability; they cannot meet the requirements of the laboratory accreditation and certification in terms of DNA fragment length and molecular weight standard. This paper has studied the preparation, purification analysis methods and quantitative analysis methods for DNA fragment including100bp,200bp,300bp,400bp,500bp,600bp,700bp,800bp,900bp and1000bp. Two purification methods, magnetic beads combining gel extraction and DHPLC, were established and tested by the gel electrophoresis, UV spectrophotometer, Chip electrophoresis and DHPLC to obtain the efficacy. The results showed that the salt, primer, DNA fragments and other impurities in PCR amplification products can be effectively removed. At the same time, a method of quantitative analysis of IDMS was established to quantitatively analyze the purified DNA fragment in the research. The study of these methods to prepare, purify and quantitatively analyze DNA fragment provides technical reference for the development of accurate, valid and traceable standard material DNA fragment.Inosine5’-monophosphate (IMP) and guamosine5’-monophosphate (GMP) have flavor. They can improve the food’s flavor tens of times via a synergistic effect with sodium glutamate and are key indicators for reflection of the quality of the chicken essence. Therefore, quality control of nucleotide in chicken essence products is extremely important. However, it is still absent that the national testing standards are; our current nucleotide testing standards are corporate standards and industry standards. The absence of national testing standards has negative impacts on the technical inspection of the nucleotide in the complex matrix. The objective of this paper was to study disodium5’-inosinate and disodium5’-guanylate (IMP and GMP) by utilizing commercial chicken essence as matrix. A method was established for precipitation of nucleotide with organic solvents along with the optimized conditions of nucleotide extraction. External standard method on high performance liquid chromatography and ionic chromatography was exerted to examine IMP and GMP in the matrix by using primary reference materials as standards. The uniformity and stability of primary reference materials proves well. There were no significant differences in characteristics of standard materials within a year. A model was developed to evaluate the uncertainty of primary reference materials of IMP and GMP. This paper provides the potential technologic references for the correlation studies on standard IMP and GMP.