The Content Determination Of Vitamin C In Vegetables And Trace Elements Iodine & Zinc In Salt And Nutrition

Vitamin C, iodine and zinc have been widely used in many fields, such as life science,modern medicine and food. The content of these elements was slight in the human body, but they play an important role in physiological function. Their content is closely related with human’s life and health, and is associated with many diseases. The studies for new analytical methods of Vitamin C, iodine and zinc by UV-Vis spectrophotometry are carried out. There are three parts in the dissertation.1. Vitamin C has the structure of Multi hydroxy lactone including enediol, which was the maximum absorption wavelength at 265 nm. Therefore, the method for determination of Vc content was established by UV spectrophotometry. The results indicated that there was a good linear relationship between the absorption and the concentration of vitamin C within 0~12.00m g/m L. The regression equation was A=0.06603C+0.01974(R2=0.99751). The limited detection of the method was 0.044 mg/m L. The determination method got the satisfactory results for the fresh vegetable samples.2. A new spectrophotometric method for determination of iodine is established, which is based on the catalytic action of KBr on the oxidation-decoloration reaction of Acid red by iodate in H2SO4 medium. The maximum absorption wavelength is 504 nm. The linear range of determination is 0~1.00μg/m L and the detection limit is 0.016μg/m L. The determination method was simple and better accurate, which got the satisfactory results for the table salt.3. A new spectrophotometric method for determination of zinc content in zinc gluconate solution is established, which is based on the chromogenic reaction of Zn(Ⅱ) with EBT in the presence of the Na Ac-HAc medium of p H 5.6. The experimental results showed that the linear range of determination is 0~2.00μg/m L and the detection limit is 0.029μg/m L. The regression equation was A=0.19457C+0.48743(R2=0.9969). The relative standard deviation is 1.24%~2.42% and the recovery rate is 99.5%~100.8%. The result is satisfactory.