RESUMO
Objective To establish an effective and reliable method for analysis of uhratrace uranium in multi-stage atmospheric particles providing the monitoring and evaluation of the content of radioactive uranium in the atmosphere.Methods A large volume six-stage-impactor sampler of atmosphere particles was used to collect aerosol samples,and uhratrace uranium in particles was digested using microwave and measured by inductively coupled plasma mass spectrometry.The filter material,digestion conditions and microwave digestion system had been optimized.Results The background of uranium level on the cellulose filter was the lowest,and the samples were digested by using HNO3-HCI (aqua regia)-H2O2 solution.Reference material SRM2783 was used to validate the accuracy of the method,and the relative error of the 238U was 7％,The detection limit of the method was 2 × 10-4ng/m3.The aerosol actual samples were analyzed using the established method.The mass concentrations of uranium in PM2.5 was in the range of 0.023-0.065 ng/m3.Conclusions The established method was effective and reliable to monitor the concentration level of ultratrace uranium in multi-stage atmospheric particles.