本文關(guān)鍵詞： 尿 鈾同位素豐度 TBP萃取色層 電感耦合等離子體質(zhì)譜(ICP-MS) 劑量估算　出處：《中國(guó)疾病預(yù)防控制中心》2012年碩士論文　論文類型：學(xué)位論文

【摘要】：鈾是廣泛存在于自然環(huán)境中的長(zhǎng)壽命放射性元素,通過(guò)飲水和食物鏈等途徑進(jìn)入人體。正常人體中的鈾主要來(lái)自于攝入的水、食物和空氣；涉鈾職業(yè)人員體內(nèi)的鈾則主要來(lái)源于核燃料循環(huán)、核設(shè)施運(yùn)行以及鈾同位素應(yīng)用等過(guò)程中的被動(dòng)攝入。鈾被人體攝入后,主要蓄積于肝臟、腎臟和骨骼中,對(duì)人體的損傷表現(xiàn)在放射性損傷和化學(xué)損傷,根據(jù)劑量大小,可引起急性或慢性中毒,誘發(fā)多種疾病。 鈾有三種天然同位素238U、235U和234U,豐度分別為99.27%、0.72%和0.0055%。在放射性核素毒性分組中,234U屬于極毒組,235U、238U屬于低毒組。由于234U的比活度相當(dāng)大,雖然其含量低,但是對(duì)劑量的貢獻(xiàn)卻不可忽略。近些年,隨著貧鈾(235U/238U豐度比約為0.25%)在世界范圍內(nèi)受到越來(lái)越多的關(guān)注,為了滿足放射性危害評(píng)價(jià)和突發(fā)事件應(yīng)急的需要,準(zhǔn)確測(cè)量人體尿中總鈾含量及其同位素豐度比,估算其劑量貢獻(xiàn)是職業(yè)危害評(píng)價(jià)和健康危害評(píng)價(jià)的重要指標(biāo)之一,也是保證公眾安全應(yīng)急分析的措施,因此,開(kāi)展尿中鈾及同位素分析方法的研究具有重要的意義。 本工作研究了TBP萃淋樹(shù)脂分離尿中鈾、電感耦合等離子體質(zhì)譜(ICP-MS)測(cè)定鈾及其同位素豐度比的方法,優(yōu)化實(shí)驗(yàn)條件并建立了分析流程。主要研究包括以下內(nèi)容： (1)建立了TBP萃淋樹(shù)脂快速分離尿樣中鈾的流程 通過(guò)鈾的標(biāo)準(zhǔn)溶液條件實(shí)驗(yàn),研究了上柱酸度及淋洗酸度、洗脫劑和柱流速對(duì)TBP萃淋樹(shù)脂分離鈾的影響,確定樣品的上柱酸度和淋洗酸度、柱流速和洗脫劑;配制模擬尿樣,研究TBP萃淋樹(shù)脂對(duì)干擾元素的分離、鈾的回收率和不同體積樣品對(duì)分離效果的影響。 (2) ICP-MS分析鈾同位素豐度比的研究 研究了同質(zhì)異位素和多原子離子干擾、儀器參數(shù)、質(zhì)量偏倚以及死時(shí)間對(duì)ICP-MS分析鈾同位素豐度比精度的影響,確定了最佳儀器參數(shù)和質(zhì)量控制方法,并對(duì)質(zhì)量偏倚和死時(shí)間進(jìn)行校正。 (3)建立并應(yīng)用ICP-MS快速分析方法分析實(shí)際尿樣中鈾和同位素豐度比 通過(guò)開(kāi)展TBP萃淋樹(shù)脂對(duì)實(shí)際尿樣分離的研究,建立了ICP-MS快速分析人體尿中鈾及同位素的方法流程,并對(duì)實(shí)際尿液樣品進(jìn)行了分析,并根據(jù)實(shí)驗(yàn)結(jié)果以及考慮便于實(shí)驗(yàn)操作,提出ICP-MS分析尿樣中鈾及同位素豐度比的最佳流程為：100mL樣品預(yù)處理,柱流速和上柱酸度分別選擇1.2mL/min、5mol/L HNO3,40mL5mol/L HNO3淋洗色層柱,去離子水作為洗脫劑,ICP-MS測(cè)定。在此條件下,尿樣中鈾的回收率達(dá)90%以上,凈化系數(shù)均大于103。 (4)對(duì)ICP-MS分析實(shí)際尿樣中鈾及同位素豐度比的結(jié)果進(jìn)行不確定度的評(píng)定。 (5)根據(jù)ICRP的劑量系數(shù)方法,利用尿中鈾濃度結(jié)合經(jīng)驗(yàn)公式計(jì)算攝入量,開(kāi)展內(nèi)照射劑量的估算,估算結(jié)果小于或略高于鈾、釷系照射的年有效劑量世界平均值。
[Abstract]:Uranium is a long life radioactive element widely existing in the natural environment, which enters the human body through drinking water and food chain. The uranium in normal human body is mainly from the water, food and air. Uranium in the human body is mainly derived from the passive intake of uranium in the nuclear fuel cycle, the operation of nuclear facilities and the application of uranium isotopes. Uranium is mainly accumulated in the liver, kidneys and bones after being ingested by the human body. The damage to human body is manifested in radiation damage and chemical injury. According to the dose size, it can cause acute or chronic poisoning and induce many diseases. Uranium has three natural isotopes, 238U 235U and 234U, the abundance of which is 99.270.72% and 0.00555.In the radionuclide toxicity group. 234U belongs to the extremely virulent group and 235U / 238U belongs to the low toxicity group. The specific activity of 234U is quite large, although its content is low, but the contribution to the dose can not be ignored in recent years. With the depleted uranium 235U / 238U abundance ratio of about 0.25) in the world more and more attention, in order to meet the needs of radiological hazard assessment and emergency response. Accurate measurement of total uranium content and isotopic abundance ratio in human urine and estimation of its dose contribution are one of the important indicators for occupational hazard assessment and health hazard assessment, and are also measures to ensure public safety emergency analysis. It is of great significance to study the analytical methods of uranium and isotopes in urine. A method for the determination of uranium and its isotopic abundance ratio in urine by TBP extraction resin and ICP-MS has been studied. The experimental conditions are optimized and the analysis flow is established. The main research includes the following: The rapid separation of uranium from urine by TBP extraction resin has been established. The effects of upper column acidity, elution acidity, eluant and column flow rate on the separation of uranium by TBP extraction resin were studied by experiments on the standard solution conditions of uranium. The upper column acidity and elution acidity of the sample were determined. Column flow rate and eluent; The effects of TBP extraction resin on the separation of interfering elements, the recovery of uranium and the effect of different volume samples on the separation were studied. Analysis of uranium isotopic abundance ratio by ICP-MS The effects of heterotopic and polyatomic ion interference, instrumental parameters, mass bias and dead time on the accuracy of ICP-MS analysis of uranium isotopic abundance ratio were studied. The optimal instrument parameters and quality control methods were determined, and the mass bias and dead time were corrected. Establishment and application of ICP-MS rapid analytical method for analysis of uranium and isotopic abundance ratios in real urine samples By studying the separation of real urine samples by TBP extraction resin, the method flow of rapid analysis of uranium and isotopes in human urine by ICP-MS was established, and the actual urine samples were analyzed. Based on the experimental results and convenient operation, the optimal procedure for the determination of uranium and isotopic abundance ratio in urine by ICP-MS was proposed as follows: 1: 100ml sample pretreatment. The column flow rate and the acidity of the column were 1.2 mL / min ~ 5 mol / L HNO _ 3 and 40 mL / L ~ 5 mol / L HNO3 elution column respectively, and deionized water was used as eluent. Under these conditions, the recovery rate of uranium in urine is over 90%, and the purification coefficient is higher than 103. The uncertainty of the results of ICP-MS analysis of the abundance ratio of uranium and isotopes in real urine samples is evaluated. (5) according to the dose coefficient method of ICRP, the intakes were calculated by uranium concentration in urine combined with empirical formula, and the internal radiation dose was estimated. The estimated results were less than or slightly higher than that of uranium. The world average annual effective dose of thorium irradiation.
【學(xué)位授予單位】：中國(guó)疾病預(yù)防控制中心
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2012
【分類號(hào)】：R142

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