针对食品中放射性核素分析的紧迫需求及分析检测技术发展滞后的现状，本项目拟制备出适用于食品中放射性核素分析、萃取性能优异、选择性良好的磁性超分子修饰的超薄石墨相氮化碳(g-C3N4)固相萃取新材料，探讨其萃取普适性和专属性，研究其与目标核素的作用本质，阐述其吸附机理，发展高效、高选择性的固相萃取新材料和新技术，结合现代分析手段，实现食品中放射性核素的快速富集与高灵敏检测。首先优化g-C3N4的制备方法，合成比表面积大、空腔大小适合目标分析核素的超薄g-C3N4纳米材料；然后将对放射性核素具有优异选择性的超分子共价键定向修饰到g-C3N4表面，使超分子的吸附功能基分散到g-C3N4的吸附位点附近，发挥g-C3N4与超分子协同萃取放射性核素的作用。结合超顺磁性载体，进一步合成专属性强的新型磁性复合材料；最后，结合现代分析手段，发展高效、高选择性的固相萃取新模式和食品中放射性核素的安全评价新技术。

Analytical techniques of radionuclides in food is poorly developed, and it is of vital urgency to make some research. The project is schemed to prepare magnetic supermolecule-modified graphitic carbon nitride being provided with superior adsorption capacity and selectivity for the radionuclides analysis of food. The universality and selectivity of adsorption materials along with its adsorption mechanism will be studied in details. Combined with modern analysis technologies, innovative solid phase extraction methods and techniques will be developed for rapid enrichment and highly sensitive detection of radionuclides in food. First, ultrathin graphitic carbon nitride with large surface area and appropriate aperture will be prepared via optimized preparation methods and suitable physical and chemical modification. Second, supermolecules with excellent selectivity towards radionuclides will be oriented immobilized on the surface of ultrathin graphitic carbon nitride in order to make the adsorption sites of supermolecules and graphitic carbon nitride adjacent, which is conducive to synergistic extraction of supermolecules and graphitic carbon nitride. Then, novel magnetic composite materials, possessing superior performance and specificity, will be prepared through combining with the magnetic carrier technology. Finally, innovative solid phase extraction methods and techniques will be found to realize the safety assessment for radionuclides in food in coordination with modern analysis technologies.