分光光度法测定粗粮中铝的含量

菜单

摘要：采用高温灰化法处理五种谷类和三种豆类，用铬天青S分光光度法测定样品的含铝量。从显色剂用量，反应时间等影响因素研究实验的最佳条件。结果表明：显色剂用量增多和时间的延长都会使吸光度先增大后减少，当显色剂用量为5 mL，显色时间为18 min时吸光度最大；其线性回归方程为y=0.73282x+0.08336，相关系数R是0.99367，铝含量在0.00-0.48 µg/mL范围内呈现良好的线性关系。粗粮的平均铝含量为27.9090 µg/g，其中嵩山小米含铝量最高，为31.754 µg/g；红豆的最少，为22.415 µg/g。可见粗粮的铝含量较低，可以放心食用。样品的加标回收率都在94 %以上。该方法精确度高，可用于多量的样品分析。51600

毕业论文关键词：粗粮；铝；铬天青S；高温灰化；分光光度法

Spectrophotometric Measurements of the Aluminum Content of the Coarse Grains

Abstract: The study on determining aluminum content of samples by using the high-temperature ashing method to deal with five kind of cereals and three kind of beans combined with chomeazurol S spectrophotometric method. The optimal conditions of the present experimental study are in terms of reagent dosage and reaction time. The results show that an increase in the amount of reagent and time will be extended so that the absorbance first increased and then decreased. The absorbance is maximum when the color developer in an amount of 5 mL and chromogenic time is 18 min. The linear regression equation is y = 0.73282x + 0.08336, the correlation coefficient R is 0.99367, and aluminum content showes a good linear relationship within 0.00-0.48 µg/mL range. The results also show that average aluminum content of the coarse grains is 27.9090 µg/g. The aluminum content of the Songshan millet is 31.754 µg/g, which is the highest of the coarse grains, whereas the red bean is 22.415 µg/g, which is the least. So, it is safety to eat whole grains. The recoveries of the coarse grains are more than 94 %. The measurement accuracy and precision is high and it can be used to analysis a large number of sample.

Key Words: Whole grains; Aluminum; Chrome azure S; Hot ash; Spectrophotometry

摘要 1

引言 2

1实验部分 2

1.1材料及药品 2

1.2仪器 3

1.3试剂 3

1.4实验原理 3

1.5实验方法 3

2结果与探讨 4

2.1最大波长的选择 4

2.2标准曲线的绘制 5

2.3实验条件的探讨 6

2.4样品测定结果 10

2.5回收率的测定 11

3结论 12

参考文献 12

致谢 14

分光光度法测定粗粮中铝的含量

引言

铝元素在地壳中含量广泛，是人类非常熟悉的一种元素，但不是人体必须的微量元素[1]，所以过量摄入铝对人有害[2,3],会引发多种疾病[4]。如铝是一种慢性神经毒素[5]，影响记忆功能，对老年痴呆有很大影响[6-8]；铝具有骨骼毒性，影响人体骨骼生长[9]；铝对免疫功能有抑制作用[10]；铝会引起贫血，影响酶活性；铝还会导致胚胎畸形[11]，肾功能失调[12,13]。所以为了人体健康，需减少铝的摄入，我们要了解铝的摄入来源。人体主要通过四大途径摄入铝：食品中本来就有的；食品饮料等含的添加剂；铝炊具，易拉罐等溶出的；其他摄入来源例如含铝的药物，净水剂等[7]。人们可以根据这些来源采取合适的措施减少铝的摄入从而减少危害。