Urinary Urinary And Isotope Determination And Internal Irradiation Evaluation

The uranium, one of a long life radioactive element exists widely in the environment. It can be assimilated by human through contaminated drinking water, food and air. The uranium which detected in bio-samples of workers who are employed in factors of nuclear fuel cycle and nuclear facility is mainly from contaminated materials. The absorbed uranium accumulates mainly in the liver, the kidney and the skeleton, and it induces radioactive damage and chemistry damage. This may cause acute or chronic diseases depending on the dose.238U,235U and234U are the three natural isotopes of uranium and the abundance is99.27%,0.725%,0.0055%respectively, of which234U belongs to the extremely toxic isotope. Since the activity of234U is quite high, we can’t neglect it to the contribution of toxic effect although the content of234U is low. In recent years, many countries have paid more attention to the depleted uranium receives around the world. The examination of total uranium and the ratios of isotopes in urine is the key issue to evaluate the hazard of radioactivity and the emergency responses to radioactive accidents.Therefore, the aim of this study is to develop the method which could be used for measuring the total uranium and isotopes in urine efficiently.This study includes following parts:(1) Establishing the method of rapidly separating uranium in urine by TBP extraction-eluting resin.The effects of acidity of TBP column and washing solution, the elution reagent and flowing speed were investigated by using the standard solution of uranium. The influences of separating uranium from matrix, the recovery of the total uranium and different volumes of samples were studied by employed the simulated urine samples.(2) The study on analyzing uranium isotopic abundance ratio by ICP-MSStudy on the influences of matrix and isobar interfere, the mass bias fractionation correction and dead time for the determination of uranium isotopic abundance by ICP-MS using uranium isotopic standard solution. Optimize the instrument parameters and the method of quality control.(3) Applying the established method to separate and measure uranium and its isotope abundance in urine by ICP-MSThe efficient of established method was assessed by combining to separate uranium using TBP extraction-eluting resin with measure uranium and the isotope abundance by ICP-MS in urine. On the basis of this evaluation, optimized the parameters as:dissolving100mL sample in HNO3+H2O2for pretreatment;1.2mL/min as the flowing speed;5mol/L HNO3adjusting the column acidity; washing column using40mL5mol/L HNO3and eluting the uranium by de-ionized water. Under this condition, the recovery of uranium in urine are more than90%and the decontamination factors of matrix are bigger than103.(4) Carried out the uncertainty evaluation of the analyzing uranium and its isotopic abundance ratio in urine samples using TBP chromatographic extraction by ICP-MS.(5) According to the method of dose factor published by ICRP. employed integrated empirical formula to calculate intaking amount of uranium on the basis of the concentration of uranium in urine. The results showed that the internal radiation dosage is consistent to the averaged dosage in references.