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氨基酸金属离子螯合物合成条件及测定方法的研究

Study of Mensuration and Preparation Method of Chelate of Amino Acid with Trace Elements

【作者】 邢颖

【导师】 赵竹青;

【作者基本信息】 华中农业大学 , 植物营养学, 2011, 硕士

【摘要】 本研究以赖氨酸、谷氨酸、甘氨酸和蛋氨酸与硫酸锌为原料采用水体系合成法制备单项氨基酸螯合锌,选用有机溶剂沉淀法分离提纯螯合物。分别探讨了氨基酸与金属离子配位比、pH、溶剂、反应温度及时间对螯合物制备过程的影响;有机溶剂种类、浸提剂与螯合液的比例(浸提比)及溶解沉淀所用溶解剂对分离测定过程的影响。用原子吸收分光光度法测定螯合率作为判断标准。并利用双硫腙显色法定性判断分离过程是否完全,与紫外光谱法配合确定螯合物是否生成。将制备及测定方法应用于上述氨基酸与铜、锰、亚铁硫酸盐螯合物及四种氨基酸按不同比例混合后的复合氨基酸螯合锌的制备及测定,以确定方法的可靠性及适用范围。购买市售氨基酸螯合微肥产品进行定性检测及螯合率的测定,为氨基酸螯合微肥产品检测方法提供参考。主要研究结果如下:1.单项氨基酸螯合锌最佳螯合条件分别为:(1)赖氨酸螯合锌:配位比(氨基酸:金属离子)2:1,pH 6.5-7.5,溶剂水,螫合温度60。C,螯合时间1 h;(2)谷氨酸螯合锌:配位比2:1,pH 5.5-7.5,溶剂水,螯合温度90℃,螯合时间0.5 h;(3)甘氨酸螯合锌:配位比2:1,pH 6.5,溶剂1‰硫酸,螯合温度90℃,螯合时间0.5 h;(4)蛋氨酸螯合锌:配位比2:1,pH4.5-5.5,溶剂1%硫酸,螯合温度80℃,螯合时间1 h。2.单项氨基酸螯合锌的最佳分离测定条件分别为:(1)赖氨酸螯合锌:浸提剂甲醇,浸提比10:1-15:1,溶解剂5‰硫酸;(2)谷氨酸螯合锌:浸提剂甲醇或乙醇,浸提比10:1-15:1,溶解剂20%硫酸;(3)甘氨酸螯合锌:浸提剂乙醇,浸提比10:1~15:1,溶解剂5%0硫酸;(4)蛋氨酸螯合锌:浸提剂甲醇,浸提比10:1-15:1,溶解剂1%硫酸。四种氨基酸螯合锌的螯合率分别为:69.09%、82.60%、86.61%和80.53%。3.单项氨基酸螯合锌的定性鉴定。双硫腙显色结果为赖氨酸锌螯合原液为紫红色而其余三种螯合原液为蓝紫色,这与赖氨酸锌的螯合率低于其余三种螯合物相符。而经分离后,氨基酸螯合物的水溶液均为蓝绿色说明螯合原液中的游离态锌离子已被有机溶剂浸提完全。而在紫外光谱中氨基酸螯合物的吸收峰较氨基酸的吸收峰有明显的位移和高度的变化,证明氨基酸与金属离子发生了螯合反应。4.单项氨基酸螯合铜、锰、亚铁螯合物的制备与检测。定性鉴定结果表明:双硫腙显色法在氨基酸螯合铜和亚铁的测定时出现偏差,主要是由于铜离子和亚铁离子本身颜色的干扰,但紫外光谱法可以弥补这一不足。对分离效果的显色表明分离条件对于其他金属离子螯合物同样适用。四种氨基酸螫合物的螯合率分别为:(1)赖氨酸铜、锰、亚铁依次为:54.26%、64.02%、61.15%;(2)谷氨酸铜、锰、亚铁依次为:84.96%、80.28%、87.10%;(3)甘氨酸铜、锰、亚铁依次为:72.18%、82.73%、91.63%;(4)蛋氨酸铜、锰、亚铁依次为:89.54%、60.89%、40.76%。对于螯合率偏低的螯合物可通过调整螯合条件来提高螯合率。5.复合氨基酸螯合锌的制备与测定。对螯合物进行定性鉴定,双硫腙显色结果和紫外光谱结果都显示有螯合物的生成,但不同的氨基酸比例使最终形成的螯合物有所差异,同时双硫腙显色结果证明分离完全。螯合率在69%-81%之间。6.对市售氨基酸螯合微肥产品进行测定。定性鉴定选用双硫腙显色法,验证结果溶液均显蓝色或蓝紫色,说明产品中含有少量金属离子。试验分别对浸提剂体积和浸提时间进行研究,通过螯合率结果确定最佳条件为:1g样品加入40 mL甲醇,浸提30 min。其中氨基酸螯合铁、锰螯合率大于90%,氨基酸螯合锌、铜大于50%。

【Abstract】 Research progress in selected lysine,glutamate,glycine,methionine and zinc sulfate the preparation of single chelate of amino acid with zinc.Highly pure chelate of amino acid with zinc were separated using precipitation fractionation by added organic solvent.Discussion the molar ratio,pH,solution,reaction temperature and time on the prep-aration. Extractant type,the ratio of extractant and chelate solution,solvent for separation and mensuration.AAS mensuration the chelation rate determined the optimum conditions. Dithizone and UV spectrum identified the nature.The mensuration and preparation metho-ds used for other singe chelate of amino acid with trace elements and zinc-amino acid compound chelates,determined the rebality and scope.Finally,the mensuration methods used for commercial amino acid trace fertilizer products,reference for this kind of produc-ts.The main results were as followed:1. The optimum preparation conditions for single chelate of amino acid with zinc synthesized were as followed:(1) Lys-Zn:molar ratio(amino acid:metal ions) 2:1,pH 6.5-7.5,solution deionized water,reaction temperature 60℃,reaction time 1h. (2) Glu-Zn: molar ratio 2:l,pH 5.5-7.5,solution deionized water,reaction temperature 90℃,reaction time 0.5 h. (3) Gly-Zn:molar ratio 2:l,pH 6.5,solution 1‰sulfurcacid, reaction temperat-ure 90℃,reaction time 0.5 h. (4) Met-Zn:molar ratio 2:1,pH 4.5-5.5,solution 1% sulfurca-id, reaction temperature 80℃,reaction time 1 h.2.The optimum separation and mensuration conditions for single chelate of amino acid with zinc synthesized were as followed:(1) Lys-Zn:Mathanol as extractant, the ratio of extractant and chelate solution between 10:1-15:1,solvent were 5‰sulphuric acid. (2) Glu-Zn:Mathanol or ethanol as extarctant, the ratio of extractant and chelate solution between 10:1-15:1,solvent were 20% sulphuric acid. (3) Gly-Zn:Ethanol as extarctant,the ratio of extractant and chelate solution between 10:1-15:1,solvent were 5%o sulphuric acid. (4) Met-Zn:Mathanol as extarctant,the ratio of extractant and chelate solution between 10:1-15:1,solvent were 1% sulphuric acid.The chelation rate were as followed:Lys-Zn 69.09%,Glu-Zn 82.60%,Gly-Zn 86.61% and Met-Zn 80.53%.3.Dithizone and UV spectrum complementary identifying the single chelate of amino acid with zinc.The result showed that the color of Lys-Zn was purple and others were blue-violet,it was consistent with chelation rate.After separated,the color of amino acid chelates solution were blue-green,showed that free Zn2+ complete separated by organic solvent.The UV spectrum of amino acids,peaks of amino acid chelates changed,proved the reaction of chelation take place.4.The method used to synthesize and determine other single chelate of amino acid with trace elements.The qualitative test result showed:The color of dithizone for chelate of amino acid with copper and ferrous were deviation,because of the color of metal ions, but UV spectrum could make up this deviation.The color of separation showed the separated conditions for chelated of amino acid with zinc could use to other amino acid chelates.The chelation rate of amino acid chelates were as followed:(1) Chelate of lysine with copper,manganese,ferrous were:54.26%,64.02%,61.15%. (2) Chelate of glutamate with copper,manganese,ferrous were:84.96%,80.28%,87.10%. (3) Chelate of glycine with copper,manganese,ferrous were:72.18%,82.73%,91.63%. (4) Chelate of methinoine with copper,manganese,ferrous were:89.54%,60.89%,40.76%.Amino acid chelates could chan-ge synthesize condition to improve chelation rate.5.The method would be used to synthesize and determine compound of amino acid with zinc.The qualitative test showed the reaction of chelation take place,but different mixed proportion had different complexes.Mean time color of dithizone showed free zinc ions complete separated.The chelation rate were between 69%-81%.6.Mensuration for amino acid chelated trace fertilizer.Dithizone identifying the nature.The color of the solution showed that little free metal ions in products.The test studied extractant volume and time,the optimum conditions were evaluted based on the chelation rate as followed:40 ml methanol added to 1g sample,extracted 30 min.The chel-ation rate of amino acid chelated ferrous,manganese were greater than 90%,amino acid chelated zinc,copper were greater than 50%.

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