苔藓中重金属检测方法的制定
发布时间:2018-01-01 12:36
本文关键词:苔藓中重金属检测方法的制定 出处:《华东师范大学》2016年硕士论文 论文类型:学位论文
更多相关文章: 苔藓 重金属 预处理 硝酸消解 ICP-MS ICP-OES
【摘要】:本课题来自国家环境保护部组织环保公益性行业科研专项的项目——重点防控重金属关键先进监测技术适用性研究,上海市环境监测中心承担了《生物中重点防控重金属关键先进监测技术研究——苔藓生物》。苔藓植物因其独特的生理构造、较强的吸附力和对污染物因子较强的敏感性,故可作为一种指示环境污染的生物材料。本文通过检测苔藓植物体内重金属的含量,指示和监测大气重金属污染状况。这不仅利于空气中重金属污染的调查、监测以及污染风险评估,反映一个地区的空气污染状况,而且制定的苔藓中重金属检测方法,可以为政府部门的科学决策和管理监控提供依据。通过收集、汇总国内外有关苔藓植物中重金属研究的相关文献资料,了解国内外苔藓样本中重金属检测分析方法,并结合我国环境监测的实际情况,梳理苔藓重金属检测分析方法。本文从质控标样及苔藓样本的筛选、样本采集与制备、样品消解方法的探讨、消解后样品检测方法的推荐等方面,初步建立苔藓中重金属元素检测的框架。第一,对质控样品及苔藓样本的选择。首先,质控样品需选择材质、待测元素相近的物质。通过对比已使用过的质控样品中各元素的含量,最终选取了茶叶、紫菜、螺旋藻和柑橘叶;其次,为使苔藓样本更具代表性和更高的污染敏感性,选取了不同地区以及同个地区具有地域代表性的不同种苔藓样本,用五点法采集了上海地区的细叶小羽藓、匍灯藓;浙江西天目山的鼠尾藓、大灰藓(街道)及江西井冈山的亚美绢藓。第二,对采集到的苔藓样本进行预处理。首先,将采集到的苔藓样本去除根部和泥土等颗粒物;其次,用自来水冲洗干净后,再用蒸馏水润洗3-4次;再次,用纱布吸干水分后,置于70℃干燥箱内烘干至恒重;最后,用陶瓷研钵研碎,过40目筛,洁净密封保存。第三,预处理后的样品消解方法的选择。常用的样品消解方法有全盐酸消解、王水消解、硝酸-高氯酸消解和全硝酸消解。首先,通过四种消解方法对预处理后样品中13种金属元素的回收率比较,选择了全硝酸消解;其次,对全硝酸消解条件进行了优化,确定样品量为0.040 g、硝酸量为4 mL和2 mL的H2O2;再次,对比了石墨炉和微波消解,通过比较两者对样品中13种金属元素的回收率以及自身仪器的优劣情况,最终选择了石墨炉消解,不仅容易满足仪器设备的要求,而且操作方法简便易掌握;最后,对石墨炉消解的时间和温度进行了优化,确定消解温度为115℃,消解时间为5 h,将样品彻底消解完全。第四,消解后样品检测方法的推荐。用电感耦合等离子体质谱仪(ICP-MS)和电感耦合等离子体发射光谱仪(ICP-OES)检测消解完后的苔藓样本中13种金属元素(Ag、Co、Cu、Mn、Ni、Pb、Zn、As、Cd、Cr、Sb、Tl、V)的含量。因两种仪器自身检出限的差异,ICP-OES只能检出含量较高的Mn、Cu、Zn、V,且检出效果也不如ICP-MS,所以最终推荐ICP-MS。对于Hg元素,使用冷原子吸收分光光度法,发现其具有较理想的检出效果。第五,利用加标回收率、精确度、准确度和空白检出限等相关指标对苔藓中重金属检测方法进行评价。最后,用苔藓样本对该检测方法进行验证,发现与实际情况相吻合,说明该检测方法具有可行性。综上,本文成功制定了苔藓中重金属检测方法——称取0.040 g样品经4 mL硝酸,2mLH2O2预消解,翌日,经115℃石墨炉消解5h后,经ICP-MS检测其重金属含量的可行性。
[Abstract]:Advanced technology - the focus of prevention and control of heavy metal monitoring key research project for this project is from the national organization of the Ministry of environmental protection environmental protection industry scientific research, the Shanghai Municipal Environmental Monitoring Center for the "biological focus on prevention and control of heavy metal key advanced research on monitoring technology of biological - Moss bryophytes. Due to its unique physical structure, strong adsorption capacity and sensitive to pollutants strong, so it can be used as an indicator of environmental pollution of biological materials. In this paper, by detecting the content of heavy metals in mosses, indicating and monitoring of atmospheric heavy metal pollution. This is not only conducive to the investigation of heavy metal pollution in the air pollution monitoring and risk assessment, reflect the status of air pollution in a region. The moss and the heavy metal detection methods, can provide the basis for government scientific decision-making and management monitoring. A collection of related documents, summary of domestic and foreign related research on heavy metals in bryophytes, find out the heavy metals at home and abroad moss samples analysis method, combined with the actual situation of China's environmental monitoring and analysis method of heavy metal detection. This paper combs moss screening from quality control samples and moss samples, sample collection and preparation of samples. The digestion method, after digestion of sample detection method recommended, preliminary establish a framework for determination of heavy metals in mosses. First, the control samples of moss and the selection of the sample. Firstly, the control samples need to choose the material elements of similar analytes. The control samples by comparing the content of each element has been used in. The final selection of tea, seaweed, spirulina and citrus leaves; secondly, in order to make the moss samples more representative and more pollution sensitivity, select a different area and the same area With different kinds of moss sample geographical representation, five point method, collected in Shanghai area leaves moss, moss moss creeping lamp; rat tail mountain in Zhejiang Province, h.plumaeforme (street) and Jiangxi Jinggangshan Yamei Entodon. Second, the collected moss samples were pretreated firstly. The collected samples of moss removal of roots and soil particles; secondly, using tap water rinse, then distilled water rinse 3-4 times; once again, with water after the dry gauze, placed in the 70 drying box drying to constant weight; finally, using a ceramic MORTAR PESTLE, 40 mesh sieve, clean sealed. Third, sample digestion method after pretreatment choice. Sample digestion method commonly used are all hydrochloric acid digestion, aqua regia digestion, nitric perchloric acid digestion and nitric acid digestion. First of all, through four kinds of digestion methods on the recovery of 13 kinds of metal elements in the samples after pretreatment ratio A, choose a full nitrate digestion; secondly, the conditions of nitric acid digestion were optimized to determine the amount of sample is 0.040 g, the nitrate amount was 4 mL and 2 mL H2O2; thirdly, compared with graphite furnace and microwave digestion, by comparing the rate of recovery of 13 kinds of metal elements in samples and their instruments the merits of the case, the final selection of the graphite furnace digestion, not only easy to meet the equipment requirements, and the operation method is simple and easy to master; finally, the graphite furnace digestion time and temperature were optimized to determine the digestion temperature is 115 DEG C, the digestion time was 5 h, the sample completely eliminated completely. Fourth, sample digestion method after recommendation by inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma atomic emission spectrometer (ICP-OES) of 13 kinds of metal elements after digestion moss samples (Ag, Co, Cu, Mn, Ni, Pb, Zn, As, Cd, Cr, Sb, Tl, V) containing Because of the difference of two. The detection limit of the instrument itself, ICP-OES can only be detected with high content of Mn, Cu, Zn, V, and the detection effect is better than ICP-MS, so the final recommendation ICP-MS. for Hg elements, absorption spectrophotometry using cold atoms, we find that it has positive ideal effect. Fifth, the use of standard addition the recovery rate, precision, accuracy and detection limit of blank related indicators to evaluate the detection methods of heavy metals in mosses. Finally, to verify the detection method using moss samples, found to coincide with the actual situation, the detection method is feasible. In summary, this paper successfully developed a method for detecting heavy metals in moss said 0.040 g samples were 4 mL nitrate, 2mLH2O2 pre digestion, the next day, the 115 C graphite furnace after digestion with 5h, the feasibility of ICP-MS to detect the content of heavy metals.
【学位授予单位】:华东师范大学
【学位级别】:硕士
【学位授予年份】:2016
【分类号】:X835
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