紫外分光光度法测定食品里的亚硝酸盐含量毕业论文稿

紫外分光光度法测定食品里的亚硝酸盐含量

摘要

目的随着人们生活水平的不断提高，食品安全问题越来越受人们重视，我国亚硝酸盐中毒事件频发，食品中的亚硝酸盐是否符合国家标准已成为研究热点，本实验测定不同时期、不同种类的卤制品和熟食品所含亚硝酸盐的含量。方法采用邻苯二胺紫外分光光度法对鞍山超市中出售的卤制品和熟食品中的亚硝酸盐含量进行测定。结果亚硝酸盐含量C(μg/mL)与吸光度A在λmax=260nm处有最大吸收峰，标准亚硝酸盐线性范围在0～5μg/mL，其线性方程为A=0.2281C-0.0025，相关系数r2=0.9999，利用此方法测定当地超市所出售的部分食品中亚硝酸盐的含量均超过国家相关标准，样品加标回收率在95%～99%之间，变异系数小于0.7%。结论该方法快速、实用、简便、准确，是测定亚硝酸盐的好方法。对当今倡导食品安全，人们维护自身利益，提倡健康饮食有深刻意义。

关键词：熟食制品；亚硝酸盐；紫外分光光度法；邻苯二胺

UlTRA VIOLET SPECTROPHOTOMETRY MEASURING

NITRITE CONTENT IN THE FOOD

ABSTRACT

Objective As people living standard rise ceaselessly, food safety problems in China by people to take seriously, gradually nitrite, food poisoning, the nitrite frequent whether accord with national standard has become a hotspot in different periods, this experiment measuration, different kinds of LuZhiPin and achievements contains nitrite content. Methods Using adjacent benzene 2 amine ultraviolet spectrophotometer in AnShan supermarket LuZhiPin and the sale in the nitrite content achievements were determined.Results Nitrite content C (μg/mL) and absorbency A lambda Max = 260 nm place has the maximum absorption peaks, nitrite concentration is 0～5μg/mL，its linear equation A=0.2281C-0.0025, correlation coefficient r2 = 0.9999, by using this method determine local supermarkets sell part of nitrate content in central Asia are food does not exceed related standards, sample is prevented. The recovery between in 95%～99%,Variation coefficient is less than 0.7%.Conclusions This method is rapid, practical, simple, accurate, is the good method of measuring nitrite. On today's advocacy of food safety, people to maintain our own interests, advocate healthy diet has profound significance.

Key words: Delicatessen products; nitrite; Ultraviolet spectrophotometer; adjacent benzene

2 aim

目录

1 前言 -------------------------------------------------------------------1

2 综述 -------------------------------------------------------------------2 2.1亚硝酸盐污染来源-----------------------------------------------------2

2.1.1 肉制品发色剂、防腐剂 ------------------------------------------2

2.1.2腌制蔬菜产生的亚硝酸盐-----------------------------------------2

2.1.3蔬菜变质腐败产生的亚硝酸---------------------------------------3

2.1.4蔬菜里自然产生的亚硝酸盐---------------------------------------3

2.1.5其他污染源-----------------------------------------------------3

2.1.6硝酸盐与亚硝酸盐-----------------------------------------------4

2.2亚硝酸盐毒性--------------------------------------------------------4

2.2．1亚硝酸盐的生物毒性---------------------------------------------4

2.2.2急性中毒原因--------------------------------------------------4

2.2.3慢性中毒（包括癌变）原因---------------------------------------5

2.2.4中毒机理------------------------------------------------------5

2.2.5亚硝酸盐中毒症状----------------------------------------------5

2.2.6亚硝酸盐中毒的抢救-------------------------------------------5

2.2.7预防措施------------------------------------------------------6 2.3 减少亚硝酸盐的方法 -------------------------------------------------6

2.3．1改进食品加工方法-----------------------------------------------6 2.3．2改变某些饮食习惯-----------------------------------------------7

2.3．3 增加维生素C --------------------------------------------------7

2.3．4 增加茶的摄入量------------------------------------------------7

2.3．5增加大蒜的摄入量-----------------------------------------------8

3 实验材料与检测方法------------------------------------------------------8 3.1 实验仪器及药品------------------------------------------------------8

3.1.1 实验仪器------------------------------------------------------8

3.1.2 实验药品------------------------------------------------------8 3.2 样品制备------------------------------------------------------------8

3.2.1 亚硝酸钠标准品配制--------------------------------------------9

3.2.2 其他药品的制备------------------------------------------------9

3.2.3 样品的制备----------------------------------------------------9

4 过程及结果讨论----------------------------------------------------------9 4.1确定最大吸收波长 ---------------------------------------------------9 4.2邻苯二胺和浓盐酸的加入量对吸光度的影响------------------------------10 4.3绘制标准曲线--------------------------------------------------------10 4.4样品分析------------------------------------------------------------11 4.5样品回收率----------------------------------------------------------11 4.6精密度实验----------------------------------------------------------12 5实验结果讨论与总结------------------------------------------------------12 5.1实验结果总结--------------------------------------------------------12