Research On Selenium Dissolution And Detection Method Of Selenium-enriched Tea

Selenium,as a trace element essential to the human body,has many physiological and pharmacological effects such as anti-oxidation,development,immunity,and cancer resistance.Selenium deficiency can cause various diseases,such as Keshan disease and Kashin-Beck disease.Therefore,selenium supplementation is an effective method to prevent diseases and treat diseases.As of now,the most convenient and most commonly used method of selenium supplementation is to eat selenium-enriched food.Generally,the selenium-enriched inorganic fertilizer or feed is absorbed into plants or animals,converted into safe organic selenium,and then processed through food engineering to obtain selenium-rich foods that can meet the requirements of human food safety.As a well-known nutritious health drink,selenium-enriched tea is very popular among people.Related scientific research,such as selenium nutrient extraction,detection,effect evaluation,etc.,has been widely concerned by researchers.Among them,the determination of selenium content in the selenium-enriched tea soaking solution is measured.However,there is still a lack of systematic research on the water solubility and selenium content of selenium-enriched tea leaves,and the sensitivity and scientificity of selenium test in aqueous solution is affected by the low solubility of selenium in water.Therefore,this paper designed a magnetic carbon nanotube enriched in selenium in aqueous solution,and then magnetic separation to test the selenium content of aqueous solution.Through the comparative study on the water solubility of selenium-enriched tea standard samples and its detection methods,the reliable solubility and detection methods of selenium were obtained.Combined with the actual work,it is proposed to provide a certain theoretical basis for the health assessment of selenium-enriched tea.The main findings are as follows:(1)Selenium in aqueous solution is enriched by synthetic magnetic carbon nanotubes,and then subjected to magnetic separation to test the selenium content of the aqueous solution.The soaking temperature,soaking time,soaking times,pH value and the extraction amount of selenium in selenium-enriched tea were studied.The results show that compared with activated carbon and pure water,magnetic carbon nanotubes have better enrichment ability for selenium under the same conditions,which helps to improve the accuracy of seleniumwater solubility analysis test.As the soaking temperature increases,the concentration of selenium in the aqueous solution shows an increasing trend.As the soaking time is prolonged,the enriched selenium concentration tends to increase,but the soaking time is extended,and the increase in selenium content in the aqueous solution becomes smaller.As the number of soaking increases,the concentration of selenium in the aqueous solution shows a downward trend.Changing the pH value found that the concentration of selenium in the aqueous solution increased to a certain extent as the pH decreased.Compared with pure water,the solubility of selenium in water will increase,but selenium is difficult to separate from activated carbon,which is not conducive to the evaluation of selenium water solubility,and its recovery rate is relatively low.(2)Selenium extracts were tested by various analytical methods,including hydride atomic fluorescence spectrometry,fluorescence spectrophotometry,inductively coupled plasma mass spectrometry,and liquid chromatography.The results show that the five test methods can meet the test requirements in terms of recovery rate and precision,and can be used as detection,comparison and verification methods.Compared with the non-national standard method,the national standard method has a narrow recovery range and high precision,and has certain comparative advantages.Among them,inductively coupled plasma mass spectrometry has the narrowest recovery range(98.8%-101.0%)and the highest precision(RSD up to 0.91%),indicating that the method is the most accurate and reliable.(3)In combination with the actual work of the inspection agency and the above experimental results,in order to compare the MCNT-ICP-MS method with the national standard method,the total selenium content was tested using commercial selenium-enriched tea,and the selenium content and precision of the four test methods were compared.The results show that the MCNT-ICP-MS method shows the lowest relative standard deviation,with the highest precision(0.31%-0.40%)and recovery(95.5%-105.2%),indicating that the MCNT-ICP-MS method is used to determine the selenium-enriched tea with high accuracy and stability in terms of selenium content.