本文關鍵詞：苔蘚中重金屬檢測方法的制定　出處：《華東師范大學》2016年碩士論文　論文類型：學位論文

  更多相關文章： 苔蘚 重金屬 預處理 硝酸消解 ICP-MS ICP-OES

【摘要】：本課題來自國家環(huán)境保護部組織環(huán)保公益性行業(yè)科研專項的項目——重點防控重金屬關鍵先進監(jiān)測技術適用性研究,上海市環(huán)境監(jiān)測中心承擔了《生物中重點防控重金屬關鍵先進監(jiān)測技術研究——苔蘚生物》。苔蘚植物因其獨特的生理構造、較強的吸附力和對污染物因子較強的敏感性,故可作為一種指示環(huán)境污染的生物材料。本文通過檢測苔蘚植物體內(nèi)重金屬的含量,指示和監(jiān)測大氣重金屬污染狀況。這不僅利于空氣中重金屬污染的調(diào)查、監(jiān)測以及污染風險評估,反映一個地區(qū)的空氣污染狀況,而且制定的苔蘚中重金屬檢測方法,可以為政府部門的科學決策和管理監(jiān)控提供依據(jù)。通過收集、匯總國內(nèi)外有關苔蘚植物中重金屬研究的相關文獻資料,了解國內(nèi)外苔蘚樣本中重金屬檢測分析方法,并結合我國環(huán)境監(jiān)測的實際情況,梳理苔蘚重金屬檢測分析方法。本文從質控標樣及苔蘚樣本的篩選、樣本采集與制備、樣品消解方法的探討、消解后樣品檢測方法的推薦等方面,初步建立苔蘚中重金屬元素檢測的框架。第一,對質控樣品及苔蘚樣本的選擇。首先,質控樣品需選擇材質、待測元素相近的物質。通過對比已使用過的質控樣品中各元素的含量,最終選取了茶葉、紫菜、螺旋藻和柑橘葉；其次,為使苔蘚樣本更具代表性和更高的污染敏感性,選取了不同地區(qū)以及同個地區(qū)具有地域代表性的不同種苔蘚樣本,用五點法采集了上海地區(qū)的細葉小羽蘚、匍燈蘚；浙江西天目山的鼠尾蘚、大灰蘚(街道)及江西井岡山的亞美絹蘚。第二,對采集到的苔蘚樣本進行預處理。首先,將采集到的苔蘚樣本去除根部和泥土等顆粒物；其次,用自來水沖洗干凈后,再用蒸餾水潤洗3-4次；再次,用紗布吸干水分后,置于70℃干燥箱內(nèi)烘干至恒重；最后,用陶瓷研缽研碎,過40目篩,潔凈密封保存。第三,預處理后的樣品消解方法的選擇。常用的樣品消解方法有全鹽酸消解、王水消解、硝酸-高氯酸消解和全硝酸消解。首先,通過四種消解方法對預處理后樣品中13種金屬元素的回收率比較,選擇了全硝酸消解；其次,對全硝酸消解條件進行了優(yōu)化,確定樣品量為0.040 g、硝酸量為4 mL和2 mL的H2O2；再次,對比了石墨爐和微波消解,通過比較兩者對樣品中13種金屬元素的回收率以及自身儀器的優(yōu)劣情況,最終選擇了石墨爐消解,不僅容易滿足儀器設備的要求,而且操作方法簡便易掌握；最后,對石墨爐消解的時間和溫度進行了優(yōu)化,確定消解溫度為115℃,消解時間為5 h,將樣品徹底消解完全。第四,消解后樣品檢測方法的推薦。用電感耦合等離子體質譜儀(ICP-MS)和電感耦合等離子體發(fā)射光譜儀(ICP-OES)檢測消解完后的苔蘚樣本中13種金屬元素(Ag、Co、Cu、Mn、Ni、Pb、Zn、As、Cd、Cr、Sb、Tl、V)的含量。因兩種儀器自身檢出限的差異,ICP-OES只能檢出含量較高的Mn、Cu、Zn、V,且檢出效果也不如ICP-MS,所以最終推薦ICP-MS。對于Hg元素,使用冷原子吸收分光光度法,發(fā)現(xiàn)其具有較理想的檢出效果。第五,利用加標回收率、精確度、準確度和空白檢出限等相關指標對苔蘚中重金屬檢測方法進行評價。最后,用苔蘚樣本對該檢測方法進行驗證,發(fā)現(xiàn)與實際情況相吻合,說明該檢測方法具有可行性。綜上,本文成功制定了苔蘚中重金屬檢測方法——稱取0.040 g樣品經(jīng)4 mL硝酸,2mLH2O2預消解,翌日,經(jīng)115℃石墨爐消解5h后,經(jīng)ICP-MS檢測其重金屬含量的可行性。
[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.

【學位授予單位】：華東師范大學
【學位級別】：碩士
【學位授予年份】：2016
【分類號】：X835

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本文編號：1364548