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摘要:本文采用分光光度法测定了街头膨化食品中铝含量。食品经硝酸-高氯酸消解后，在乙酸－乙酸钠作为缓冲介质，铝离子和铬天青S、溴化十751烷基三甲胺反应形成蓝色的三元配合物。实验结果表明，在pH=6.0的HAc-NaAc缓冲溶液中进行，此时最大吸收波长位于620nm处，最佳显色时间为20min，铝含量有良好的线性关系，相关系数r=0.9977,检测下限为0.05 mg/l。该方法用于实际样品中铝含量的测定，实验结果准确、操作简单快速，可以获得令人满意的实验结果。33046
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采用了双硫腙分光光度法测定食品中铅含量。采用双硫腙为显色剂，控制溶液的pH 为8.5，在510 nm 波长处测定吸光度，利用标准曲线求出铅含量。并讨论了溶液pH、反应时间、络合剂用量对吸光度的影响。该方法检测下限为0.03 mg/l,相关系数r=0.9982。
本文测定了部分街头膨化食品中的铅、铝含量，并对铅、铝含量是否符合国家标准含量以及对于现代人食用街头膨化食品是否对身体有伤害进行了讨论 。
毕业论文关键词: 分光光度法；食品；铝；铅；分析
Study on content of aluminum and plumbum in the streets of junk food
Abstract:It determined the aluminum content in junk food by spectrophotometry . After food was digested by nitric acid and perchloric acid ,the temary complex was formed via the reaction trivalent aluminum ion with chrome azurol S and hexadelyl trylammonium bromide in the buffer of acetic acid-sodium acetate. The results showed that in pH = 6.0 HAc-NaAc buffer solution, the maximum absorption wavelength is located at 620 nm, the best color time is for 20 minutes,,the content of aluminum has good linear range of calibration curve.Correlation coefficient r=0.9977. Its detection limit is 0.05mg/l.The mothod could be applied with the analysis of the aluminum content in food with satisfactory results and speediness.
Adopted the dithizone spectrophotometry to determine the content of plumbum in food. Using dithizone as chromogenic agent, control solution of pH 8.5, determination of absorbance at 510 nm wavelength, using the standard curve to get the content of plumbum. And it discussed the influence of the solution pH, reaction time, complexing agent dosage on the absorbance. This method detection limit is 0.03mg/l. Correlation coefficient r=0.9982.
This article determined the content of aluminum and plumbum in part of streets of junk food，and whether the content of plumbum and aluminum is in compliance with national standards .It also discussed whether streets of junk food will be harmful to modern human.
Keywords: spectrophotometry ; food ; aluminum ; plumbum ; analysis
目录
1 前言 1
1.1食品中铅的危害 1
1.2 铝的摄入途径 1
1.3铝对人体的危害 2
1.4食品中金属元素含量的检测方法 2
1.4.1分光光度法 2
1.4.2石墨炉原子吸收光谱法 3
1.4.3间接火焰原子吸收法 3
1.4.4电感耦合等离子体发射光谱法 3
1.4.5电感耦合等离子体质谱法 4
1.5分光光度法的原理 4
1.6分光光度法的分类 5
1.6.1普通光度法 5
1.6.2胶束增溶光度法 5
1.6.3双波长光度法 5
1.6.4催化光度法 5
2 测膨化食品中铝含量的实验内容与实验结果与讨论 6
2.1 测膨化食品中铝含量的实验内容 6
2.1.1试剂与材料 6
2.1.2 实验仪器 6
2.1.3 标准曲线的绘制 6
2.1.4 未知样品的测定 9