环境中痕量铀和铬检测新方法的研究

发布时间：2018-04-26 09:44

本文选题：铀(VI) + 铬(VI)　；参考：《南华大学》2015年硕士论文

【摘要】：对于环境中痕量铀和铬的测定在卫生检验中的研究意义和研究现状进行详细的介绍。介绍了样品处理中浊点萃取以及二次萃取技术的概念和基本原理。阐述了本文新建立的环境样品中痕量铀和铬检测新方法研究的定量依据和基本原理。第二章在稀硫酸介质中,铀以铀酰离子(UO22+)的形式存在,它能催化溴酸钾氧化荧光试剂罗丹明G(Rh G)的氧化还原反应,导致体系的荧光强度降低,根据反应体系的荧光强度降低值(ΔF)与铀酰离子的浓度的线性关系,建立一种新的测定环境样品中铀的催化荧光法。经实验发现,催化荧光体系的最佳激发波长和发射波长分别为525 nm和552 nm。最佳优化条件下,反应体系的荧光强度降低值ΔF与铀(VI)浓度在6.62×10-9~5.2×10-8 g/m L范围内线性关系良好,工作曲线的线性回归方程为ΔF=22.2+52.6 c(g/m L),相关系数r=0.9992。方法检出限为2.0×10-9 g/m L。新建方法可用于水样中铀的测定,RSD为2.8%-4.6%,样品加标回收率为99.3%~102.5%。第三章本章在第二章的基础上,研究先采用二次浊点萃取技术对样品中的痕量铀进行富集,再应用U-salophen配合物能光催化溴酸钾氧化罗丹明G的特点,将二次浊点萃取技术与光催化动力学荧光检测法相互结合起来,建立一种测定复杂样品中微量铀的新方法,新建方法能应用于铀的水质检验。在实验条件下,在MES-Tris缓冲液中,通过加入表面活性剂Triton X-114,对样品中铀进行二次浊点萃取,可将样品中的铀酰阳离子萃取而富集,再加入salophen配体,使其与salophen配合形成U-salophen配合物。U-salophen配合物能产生光催化作用,加速溴酸钾氧化罗丹明G反应,使其荧光强度减弱,荧光强度减弱值与铀的含量呈直线关系,据此建立一种催化动力学光度法测定环境水中铀(VI)的新方法。该光催化荧光体系的最佳激发波长和发射波长分别为525 nm和553 nm。实验结果表明,在最佳优化实验条件下,反应体系的荧光值改变值(ΔF)与铀(VI)的浓度在4.0×10-12~4.0×10-11 g/m L范围内呈良好线性关系,检出限为1.46×10-12g/m L。工作曲线的线性回归方程为ΔF=11.9-31.22c(g/m L)。新建方法用于水中铀酰的测定,RSD为2.6%-3.8%,加标回收率为99.6%-101.5%。与第二章比较该方法检测下限更低。第四章在醋酸-醋酸钠缓冲溶液介质中,罗丹明6G具有很强的荧光,溴酸钾能氧化罗丹明6G(Rh6G)使其荧光强度减弱但速度很慢。痕量铬(VI)的加入能够加快该反应的速度,使溶液的荧光强度迅速降低。荧光强度降低值随铬的加入而增大,据此建立一种新的催化动力学荧光法测定环境水中铬(VI)的方法。经实验发现,该催化荧光体系的最佳激发波长和发射波长分别为525 nm和555 nm。在优化反应和测定条件,在λmax=555 nm时,荧光值改变值(ΔF)与铬(VI)的浓度在1.0×10-8~1.4×10-7 g/m L范围内呈良好线性关系,工作曲线的线性回归方程为ΔF=2646.4c(μg/m L)-4.57。方法检出限为3.46×10-9 g/m L,相对标准偏差小于4.9%,加标回收率为95.5%-102.9%。本方法操作简便、快速、使用仪器设备简单。
[Abstract]:The significance and current status of the determination of trace uranium and chromium in the environment were introduced in detail. The concept and basic principles of cloud point extraction and two extraction in sample treatment were introduced. The quantitative basis and basic origin of the new method for trace uranium and chromium detection in the newly established environmental samples were described. In the second chapter, in the dilute sulfuric acid medium, uranium exists in the form of uranyl ion (UO22+), which can catalyze the redox reaction of the potassium bromate oxidation fluorescent reagent Luo Danming G (Rh G), which leads to the reduction of the fluorescence intensity of the system. A new determination is established based on the linear relationship between the fluorescence intensity reduction value of the reaction system and the concentration of uranyl ions. The Catalytic Fluorescence Method of uranium in environmental samples shows that the optimum excitation wavelength and emission wavelength of the catalytic fluorescence system are 525 nm and 552 nm., respectively. The linear regression equation of the reduction value of the fluorescence intensity of the reaction system Delta F and uranium (VI) concentration in the range of 6.62 x 10-9~5.2 10-8 g/m L is linear. For Delta F=22.2+52.6 C (g/m L), the correlation coefficient r=0.9992. method detection limit is 2 x 10-9 g/m L. new method can be used for the determination of uranium in water samples, RSD is 2.8%-4.6%, the sample addition recovery rate is 99.3%~102.5%. third chapter on the basis of the chapter of the second chapter, the study first uses two turbid extraction technology to enrich the trace uranium in the sample, and then should be used. The U-salophen complex can be used to catalyze the oxidation of rhodamine G by potassium bromate, and a new method for the determination of trace uranium in complex samples is established by combining the two cloud point extraction technology with the photocatalytic kinetic fluorescence detection method. The new method can be applied to the water quality test of uranium. Under the experimental conditions, the method can be used in the MES-Tris buffer solution. The surfactants Triton X-114 was added to the two cloud point extraction of uranium in the sample. The uranium acyl cation in the sample could be extracted and enriched, then salophen ligand was added to form the U-salophen complex.U-salophen complex with salophen to produce photocatalytic activity. The oxidation of rhodamine G reaction with potassium bromate was reduced, and the fluorescence intensity was reduced. A new method for the determination of uranium (VI) in environmental water by catalytic kinetic spectrophotometric method is established. The optimum excitation wavelength and emission wavelength of the photocatalytic fluorescence system are 525 nm and 553 nm. respectively. The results show that the fluorescence value of the reaction system is changed under the optimum optimum experimental conditions. The concentration of variable value (delta F) and uranium (VI) has a good linear relationship with the range of 4 x 10-12~4.0 x 10-11 g/m L. The linear regression equation of the detection limit of 1.46 x 10-12g/m L. is delta F=11.9-31.22c (g/m L). The new method is used for the determination of uranyl in water, RSD is 2.6%-3.8%, and the rate of recovery is compared with the second chapter. The lower limit is lower. In the fourth chapter, Luo Danming 6G has a strong fluorescence in the medium of acetic acid sodium acetate buffer solution. Potassium bromate can oxidize Luo Danming 6G (Rh6G) to weaken the fluorescence intensity but slow down. The addition of trace chromium (VI) can accelerate the reaction speed and reduce the fluorescence intensity of the solution rapidly. The decrease of fluorescence intensity with the addition of chromium. In addition, a new method for the determination of chromium (VI) in environmental water by catalytic kinetic fluorescence is established. It is found that the optimum excitation wavelength and emission wavelength of the catalytic fluorescence system are 525 nm and 555 nm. respectively in the reaction and determination conditions. At the time of lambda max=555 nm, the concentration of the fluorescence value (delta F) and chromium (VI) is 1 x 10-8~1.4. There is a good linear relationship in the range of X 10-7 g/m L. The linear regression equation of the working curve is delta F=2646.4c (mu g/m L) -4.57. method, the detection limit is 3.46 x 10-9 g/m L, the relative standard deviation is less than 4.9%, the addition recovery rate is 95.5%-102.9%. this method is simple, quick, and easy to use instrument and equipment.

【学位授予单位】：南华大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X830

【共引文献】