土壤中锰、铬离子含量的测定正文.doc

土壤中锰铬离子含量的测定一 试验部分1.1试剂与仪器铬标准溶液：称取0.2827g重铬酸钾溶于100ml水中，并以此溶液稀释至10ug/ml。锰标准溶液：称取0.3073g锰酸钾溶于水中，转入100ml容量瓶。硫酸-磷酸混合液配成5%。二苯碳酰二肼，高锰酸钾，叠氮化钠，高碘酸钾。所用试剂均为分析纯。752型分光光度计。1.2铬的测定方法1.21标准曲线绘制分别准确吸取铬标准液0.00、0.15、0.30、0.60、 0.90、1.20、1.50mL于15mL比色管中，加入1.5ml硫酸磷酸混合液，用水稀释至标线，摇匀，分别加入0.6mL二苯碳酰二肼溶液摇匀，10min后用3cm比色管于波长540nm处测定吸光率，以铬含量为横坐标，吸光度为纵坐标绘制标准曲线。1.22样品分析1.消化准确称取0.5g土壤于100mL烧杯中，加少许水湿润，加入适当等量的浓硫酸.浓磷酸，盖上表面皿，放在电炉上加热至冒白烟，直至消化液呈灰色，取下让其冷却，滴加浓硝酸，再置于电炉上加热至冒白烟，土壤变白。2.沉淀分离将消化液残渣一同移入10mL离心管，离心后将上层清夜移入100mL容量瓶中，用水冲洗离心管壁，将其再次离心，将上层清夜移入100mL容量瓶中，稀释至标线。3.氧化还原准确吸取10mL上述（2）中容量瓶里的溶液于50mL烧杯中，滴加5%高锰酸钾溶液至微紫，置于水浴上煮沸，（若煮沸过程中紫色褪去，应再加高锰酸钾至紫色不再褪去）此时加入叠氮化钠，恰加至紫色褪去，将其置于冷水中迅速冷却。4.比色将上述（3）中溶液转移到15mL比色管中，以下操作方法同标准曲线。1.3锰的测定方法1.31标准曲线绘制分别吸取锰标准液0.00、0.15、0.30、0.45、0.60、0.75、0.90mL于15ml比色管中，用水稀释至标线，然后进行显色测定操作步骤。以锰含量为横坐标，吸光度为纵坐标绘制标准曲线。1.32样品分析1.消化准确称取0.5g土壤于100mL烧杯中，加少许水湿润，加入HNO3-HCIO4混合酸，盖上表面皿，放在电炉上加热至冒白烟，再加入少量HCIO4，冷却。2.沉淀分离将消化液残渣一同移入10mL离心管，离心后将上层清夜移入100mL容量瓶中，用水冲洗离心管壁，将其再次离心，将上层清夜移入100mL容量瓶中，稀释至标线。3.氧化取10ml上述（2）中溶液，加入过量KIO4，充分反应，使其显色完全，待用。4.比色将上述（3）中溶液转移到15mL比色管中，以下操作方法同标准曲线。二、结果与讨论铬离子含量的测定浓度（ppm）吸光度均值0.10.0890.0880.0830.0870.20.2610.2700.2690.2670.40.4190.4250.4360.4270.60.5060.5080.5150.5100.80.5190.5200.5140.5181.00.6530.6480.6540.652锰离子含量的测定浓度（ppm）吸光度均值100.1170.1150.1080.113200.1590.1620.1650.162300.2750.2780.2830.279400.3830.3800.3760.380450.4520.4580.4560.455500.4730.4730. 4760.474600.5870.5980.6090.598待测样品吸光度均值函数浓度锰0.2530.2570.2510.254Y0.00986X0.0066826.44铬0.2450.2530.2490.249Y0.6137X0.079360.28由此可以推算出，土壤中锰的含量(26.44150) 0.57.932mg/g，铬的含量（0.28150）0.584ug/g1 吴冀华. 酶促茶油酯交换制类可可脂的研究D.郑州:郑州粮食学院,1995. 2 Shimada Y,Sugihara A,Maruyama K. Production of Structured Lipid Containing Docosahexaenoic and Caprylic Acids Using Immobilized Rhizopus delemar LipaseJ.Journal of Fermentation and Bioengineering,1996,(04):299-303. 3 徐凤彩. 酶工程M.北京:中国农业出版社,2001.174-184. 4 Sakurai C,Margolin A L,Russell A J. Control of Enzyme Enantio- selectivity by the Reaction MediumJ.Journal of the American Chemical Society,1988.7236-7240.doi:10.1021/ja00229a061. 5 周国伟,李干佐,李越中. 微乳液和微乳液凝胶中脂肪酶催化的酯合成反应J.化学学报,2001,(03):344-349.doi:10.3321/j.issn:0567-7351.2001.03.008. 6 Xu X,Mu H,Skands A R H. Parameters Affecting Diacylglycerol Formation During the Production of Specific-Structured Lipids by Lipase-Catalyzed InteresterificationJ.Journal of the American Oil ChemistsSociety,1999,(02):175-181. 7 Shishikura A,Fujimoto K,Suzuki T. Improved Lipase-Catalyzed Incorporation of Long-Chain Fatty Acids into Medium-Chain Triglycerides Assisted by Supercritical Carbon Dioxide ExtractionJ.Journal of the American Oil ChemistsSociety,1994,(09):961-967.doi:10.1007/BF02542262. 8 Rubingh D N. Protein Engineering from a Bioindustrial Point of ViewJ.Current Opinion in Biotechnology,1997.417-422. 9 You L,Arnold F H. Directed Evolution of subtillisin E in Bacillus subtilis to Enhance Total Activity in Aqueous DimethylformamideJ.Protein Engineering,1996,(1):77-83.doi:10.1093/protein/9.1.77. 10 张红缨,孔祥铎,张令. 蛋白质工程的新策略-酶的体外定向进化J.科学通报,1999,(11).doi:10.3321/j.issn:0023-074X.1999.11.001. 11 Reetz M T. Evolution in the Test Tube as a Means to Create Enantioselective Enzymes for Use in Organic SynthesisJ.Science Progress,2000,(02):157-172. 12 Russell A J,Klibanov A M. Inhibitor-induced Enzyme Activation in Organic SolventsJ.Journal of Biological Chemistry,1988.11624-11626. 13 Dabulis K,Klibanov A M. Molecular Imprinting of Protein and Other Macro- molecules Resulting in New AdsorbentsJ.Biotechnology and Bioengineering,1992.176-183.doi:10.1002/bit.260390209. 14 Okahata Y,Hatano A,Ijiro K. Enhancing Enantioselectivity of a lipid-coated Lipase via Imprinting Methods for Esterification in Organic SloventsJ.Tetrahedron:Asymmetry,1995.1311-1322.doi:10.1016/0957-4166(95)00165-L. 15 Lalonde J J,Govardhan C,Khalaf N. C