改进的原子吸收法测定土壤样品中的6种重金属元素
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摘要
原子吸收法是常用的测定重金属元素的方法 ,由于土壤中有机物含量较高,因此在测定土壤样品时,主要的影响因素有消解方法、消解仪器、消解体系、消解温度、加酸顺序、测定时掩蔽干扰元素的方法以及仪器的测量条件。在研究上述影响因素后认为,选择电热板作为消解土壤样品的仪器;选择HCl-HNO3-HF-HClO4全量分解的方法;控制消解温度为140℃;溶解样品时先赶尽HCl,最后加入HClO4以进一步分解样品中的有机物并避免盐酸与高氯酸同时存在而导致的铬元素分析结果偏低;选用氯化铵作为掩蔽剂,以掩蔽铁、铝、钙和镁等共存离子的干扰,使样品前处理简便快速,且一次溶样可依次测定铜、锌、铬、铅、镉和镍6种元素,提高了工作效率,节约分析成本。此外,测定结果的灵敏度受仪器的测量条件的影响很大,应根据样品溶液的浓度范围选择适合的波长,根据各元素的特殊性质选择狭缝的宽度,火焰类型等,以提高测量的灵敏度。对国家一级标准物质的分析测试,取得了满意的结果。分析方法精密度Cu、 Zn、 Cr、 Pb、 Cd和Ni分别为3.39%、 1.52%、1.77%、 2.26%、 4.08%和4.00%;检出限分别为3μg·g~(-1)、 3μg·g~(-1)、 5μg·g~(-1)、 2μg·g~(-1)、 0.1μg·g~(-1)和0.5μg·g~(-1)。
This paper discussed the effect of different dissolving instruments, dissolving system,dissolving temperature and acid adding method on soil sample deterring results, as well as the methods of masking the interference elements. The decomposition method of HCl-HNO_3-HF-HClO_4 was achieved with the company of electrothermal plate, which was used to dissociate and control the temperature at 140 ℃ while the soil samples were dissolved. In order to avoid HCl and HClO_4 residual, the HCl was added in the first place, followed by HClO_4·NH_4Cl was used to avoid the interference of Fe, Al, Ca, Mg and other coexistence ion and accelerate the pretreatment process. By using this method, Cu, Zn, Cr, Pb, Cd and Ni could also be analyzed in sequence in a single dissolution, which significantly improved the working efficiency and saved the cost of analysis. In addition, the conditions of the instrument also have a great impact on the sensitivity of the result,which could be improved by selecting the proper wavelength according to the range of the sample, the width of slit and the type of flame. By analyzing national standards material GBW07401, the standard deviation of Cu, Zn, Cr, Pb, Cd and Ni was found to be 3.39%, 1.52%, 1.77%, 2.26%, 4.08%,1.00% respectively and the detection limits to be 3 μg·g~(-1), 3 μg·g~(-1), 5 μg·g~(-1), 2 μg·g~(-1), 0.1 μg·g~(-1),0.5 μg·g~(-1) correspondently.
This paper discussed the effect of different dissolving instruments, dissolving system,dissolving temperature and acid adding method on soil sample deterring results, as well as the methods of masking the interference elements. The decomposition method of HCl-HNO_3-HF-HClO_4 was achieved with the company of electrothermal plate, which was used to dissociate and control the temperature at 140 ℃ while the soil samples were dissolved. In order to avoid HCl and HClO_4 residual, the HCl was added in the first place, followed by HClO_4·NH_4Cl was used to avoid the interference of Fe, Al, Ca, Mg and other coexistence ion and accelerate the pretreatment process. By using this method, Cu, Zn, Cr, Pb, Cd and Ni could also be analyzed in sequence in a single dissolution, which significantly improved the working efficiency and saved the cost of analysis. In addition, the conditions of the instrument also have a great impact on the sensitivity of the result,which could be improved by selecting the proper wavelength according to the range of the sample, the width of slit and the type of flame. By analyzing national standards material GBW07401, the standard deviation of Cu, Zn, Cr, Pb, Cd and Ni was found to be 3.39%, 1.52%, 1.77%, 2.26%, 4.08%,1.00% respectively and the detection limits to be 3 μg·g~(-1), 3 μg·g~(-1), 5 μg·g~(-1), 2 μg·g~(-1), 0.1 μg·g~(-1),0.5 μg·g~(-1) correspondently.
引文
[1]环境保护部,国土资源部.全国土壤污染状况调查公报[EB/OL].[2014-04-17].http://g.mlr.gov.cn/201701/t20170123-1428712.html
[2]侯张明.便携式X荧光仪在测定土壤中Cr、Pb等重金属元素的应用[J].中国高新技术企业,2016,(20):41-42.
[3]张思冲,周晓聪,叶华香,等.X射线荧光光谱法测定哈尔滨城郊菜地土壤重金属[J].中国农学通报,2009,25(13):230-233.
[4]张力.环境监测行业利用能量色散X射线荧光仪测定土壤中重金属方法探讨[J].中国高新技术企业,2016,(8):76-77.
[5]杨桂兰,商照聪,李良君,等.基于均匀设计的土壤重金属PXRF检测方法优化研究[J].浙江农业学报,2016,28(12):2 123-2 129.
[6]李敏,胡艳丽,庞春燕,等.ICP-AES和ICP-MS法测定不同环境样品中重金属镉的比较[J].安徽农业科学,2016,44(12):87-88.
[7]刘建军,王玉功,倪能,等.电感耦合等离子体质谱(ICP-MS)法测定农产品地土壤中铅、镉、铬消解方法的改进[J].中国无机分析化学,2016,6(1):10-13.
[8]范菲菲,阎献芳,周玮,等.不同前处理方式的ICP-MS法测定贵州省典型土壤中7种重金属元素[J].江苏农业科学,2016,44(1):329-332.
[9]冯丽萍.电热板消解ICP法测定土壤中10种重金属元素[J].广东化工,2017,44(7):230-231.
[10]马莉,司晗.微波消解样品-电感耦合等离子体质谱法同时测定土壤中重金属元素和稀土元素[J].环境科学导刊,2016,35(2):88-91.
[11]李自强,李小英,钟琦,等.电感耦合等离子体质谱法测定土壤重金属普查样品中铬铜镉铅的关键环节研究[J].岩矿测试,2016,35(1):37-41.
[12]张霖琳,梁宵,加那尔别克·西里甫汗,等.在土壤及底泥重金属测定中不同前处理和分析方法的比较[J].环境化学,2013,32(2):302-306.
[13]龙加洪,谭菊,吴银菊,等.土壤重金属含量测定不同消解方法比较研究[J].中国环境监测,2013,29(1):123-126.
[14]王小琳,栾桂云,管泽民,等.土壤中总铬测定方法的比较研究[J].土壤(Soils),2010,42(3):497-501.
[15]安裕敏.土壤铬的测定方法探讨[J].微量元素与健康研究,2007,24(5):45-47.
[16]张祯,张为人,孔瑾.火焰原子吸收法测定土壤中铬前处理方法的研究[C]//中国环境科学学会学术年会论文集,2010:1 911-1 912.
[2]侯张明.便携式X荧光仪在测定土壤中Cr、Pb等重金属元素的应用[J].中国高新技术企业,2016,(20):41-42.
[3]张思冲,周晓聪,叶华香,等.X射线荧光光谱法测定哈尔滨城郊菜地土壤重金属[J].中国农学通报,2009,25(13):230-233.
[4]张力.环境监测行业利用能量色散X射线荧光仪测定土壤中重金属方法探讨[J].中国高新技术企业,2016,(8):76-77.
[5]杨桂兰,商照聪,李良君,等.基于均匀设计的土壤重金属PXRF检测方法优化研究[J].浙江农业学报,2016,28(12):2 123-2 129.
[6]李敏,胡艳丽,庞春燕,等.ICP-AES和ICP-MS法测定不同环境样品中重金属镉的比较[J].安徽农业科学,2016,44(12):87-88.
[7]刘建军,王玉功,倪能,等.电感耦合等离子体质谱(ICP-MS)法测定农产品地土壤中铅、镉、铬消解方法的改进[J].中国无机分析化学,2016,6(1):10-13.
[8]范菲菲,阎献芳,周玮,等.不同前处理方式的ICP-MS法测定贵州省典型土壤中7种重金属元素[J].江苏农业科学,2016,44(1):329-332.
[9]冯丽萍.电热板消解ICP法测定土壤中10种重金属元素[J].广东化工,2017,44(7):230-231.
[10]马莉,司晗.微波消解样品-电感耦合等离子体质谱法同时测定土壤中重金属元素和稀土元素[J].环境科学导刊,2016,35(2):88-91.
[11]李自强,李小英,钟琦,等.电感耦合等离子体质谱法测定土壤重金属普查样品中铬铜镉铅的关键环节研究[J].岩矿测试,2016,35(1):37-41.
[12]张霖琳,梁宵,加那尔别克·西里甫汗,等.在土壤及底泥重金属测定中不同前处理和分析方法的比较[J].环境化学,2013,32(2):302-306.
[13]龙加洪,谭菊,吴银菊,等.土壤重金属含量测定不同消解方法比较研究[J].中国环境监测,2013,29(1):123-126.
[14]王小琳,栾桂云,管泽民,等.土壤中总铬测定方法的比较研究[J].土壤(Soils),2010,42(3):497-501.
[15]安裕敏.土壤铬的测定方法探讨[J].微量元素与健康研究,2007,24(5):45-47.
[16]张祯,张为人,孔瑾.火焰原子吸收法测定土壤中铬前处理方法的研究[C]//中国环境科学学会学术年会论文集,2010:1 911-1 912.