浊点萃取分光光度法测头发中锌的含量

针对传统萃取分光光度法测定头发中的锌含量,需要使用苯、四氯化碳等有机毒性试剂萃取锌-双硫腙疏水配合物,存在污染环境和操作费时之弊端,采用浊点萃取法代替有机毒性试剂萃取锌-双硫腙红色疏水配合物,用分光光度法测定人发中的锌含量.选择湿法消化处理头发试样,选取非离子表面活性剂曲拉通X-114和硫酸铵作为浊点萃取体系,对锌-双硫腙红色疏水配合物进行浊点萃取;实验测定了浊点萃取物的最大吸收波长、萃取剂的浓度、萃取剂的测定、硫酸铵的用量及显色体系的pH和显色剂的用量对吸光度的影响,并进行回收率实验.实验结果表明浊点萃取的配合物最大吸收波长为527 nm、质量分数2％的萃取剂为0.3～1.0 mL、硫酸铵1.2g、pH为4.5、显色剂的用量为0.2～0.8 mL,锌含量的线性范围为0.2～1.2 μg/mL,线性回归方程为A=0.435 9 c（μg/mL） ＋0.014 8,相关系数r=0.997 3,表观摩尔吸光系数为5.894×10 000 L/（mol·cm）,测定结果的相对偏差为2.4％,回收率为98.76％～102.2％.用该法测定头发中的微量锌,结果令人满意,对食品中微量锌的测定具有一定应用价值.

Measuring content of zinc in hair by cloud point extraction spectrophotometry

For the drawbacks that measuring the zinc content in hair with traditional extraction spectrophotometric method need to use benzene,carbon tetrachloride and other organic toxic reagent to extract Zn-dithizone red hydrophobic complexes leads to a result of pollution of the environment and time-consuming extraction operation,cloud point extraction method was used to extract Zn-dithizone red hydrophobic complexes in stead of organic toxic reagent and the content of zinc in hair is measured with spectrophotometric method.Selecting wet digestion processing hair samples and non-ionic surfactant Triton X-114 and ammonium sulfate as the cloud point extraction system,Zn-dithizone red hydrophobic complexes are carried on the cloud point extract.The experiment determines the influences of the maximum absorption wavelength of the complexes,the density of the extracting agent,the determination extracting agent,the amount of ammonium sulfate,the pH of colored system,the amount of chromogenic agent on absorbance,and carries on the returns-ratio experiment.Experimental results show that the maximum absorption wavelength of the complexes is 527 nm,the extractant of 2％ is 0.3～1.0 mL,the amount of ammonium sulfate is 1.2 g,the determination of pH is 4.5,the dosage range of chromogenic reagent is 0.2 0.8 mL,the proportional range of zinc content is 0.2-1.2 μg/mL,the equation of linear regression A=0.435 9 c（μg/mL） ＋ 0.014 8,the coefficient of correlation r=0.997 3,the apparent molar absorptivity is 5.894 × 10 000 L/（mol · cm） and relative deviation of the test result is 2.4％.Determining the micro zinc in the hair in this way can get a satisfying result：coefficient of recovery is 98.76％-102.2％,which has a certain application value for de terminating micro zinc in food.