High Performance Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry For Selenium Speciation Analysis

The element speciation analysis is a very important research field for analytical science.The availabity or toxicity of element in vivo not only depends on total element quantity but also its actual chemical form.So,the total element quantity has not give the migration,transformation and the final destination of element in the environment.Many analytical methods have been tried for speciation studies.However,it soon became evident,through a series of continuing conceptual and technical developments,that only hyphenation of separation techniques and element-or molecule-selective detection systems provides the basis for trustworthy speciation analysis.Inductively coupled plasma-mass spectrometry(ICP-MS)has the advantages of high sensitivity,wide linearity range,multi-elemental and multi-isotope detection capabilty,minimum matrix effects.ICP-MS has a wide range use to trace element analysis.High performance liquid chromatography(HPLC)is the most widely used to separation techniques due to its merits of multiseparation modes availability,powerful separation capability,and good reproducibility.HPLC often combines with ICP-MS with simple interface.HPLC-ICP-MS has a wide application to element speciation analysis.The element species affected environmental behaviors,ecological effects and physiological functions,and human health.Its existence is closely related to the chemical form of the elements.Selenium is an essential trace element for humans,due to its anti-cancer properties,removing free radicals,anti-aging,etc.It has shown that selenium deficiency probably affects about 40 diseases such as Keshan disease,Kaschin-Beek disease,diabetes and AIDS.However,high selenium intake can also cause selenium poisoning.Selenium deficiency or excess is adverse to human body.In this paper,Maca,Burdock,Radix Puerariae and Panax notoginseng were chosen to research objective matter,and HPLC-ICP-MS were used as detection of the selenium speciation.The main contents and results were shown as follows:1.An novel analytical method for selenium species of selenocystine(SeCys2),selenite(Se(?)),selenomethionine(SeMet)and selenate(Se(?))has been developed using HPLC-ICP-MS.80Se was used as detection isotope.CH4 was used for DRC gas which reduced interference of 40Ar40Ar+ in argon gas.Two extration reagents with ultrasonic mode have been evaluate in order to obtain highest selenium extraction efficiency in analytes.Comparing to water,the extraction efficiency by proteinase-lipase was the best.The detection limit of this method for SeCys2,Se(?),SeMet and Se(?)was 0.088?0.033?0.30 and 0.17 ng·mL-1,respectively.The correlation coefficients were more than 0.9995.The four selenium speciation in Maca and Burdock were found.The inorganic selenium is main selenium species in Burdock.The recoveries of four selenium species ranged from 95.4%to 108.0%.The method is simple,rapid,and sensitive.The four selenium speciation was completely separated within 7 min.2.An new analytical method for determination of selenium species in Panax notoginseng was established by HPLC-ICP-MS.The highest selenium extraction efficiency in Panax notoginseng was gained using proteinase-lipase in aqueous solution.The detection limit of SeCys2,Se(IV),SeMet and Se(VI)was 0.075?0.043?0.375 and 0.25 ng·mL-1,respectively.The correlation coefficients were more than 0.9993.The RSD(n=6)was range from 2.6%to 3.5%.In Panax notoginseng,the concentration of SeCys2,Se(?),SeMet and Se(?)was 0.0284,0.0856,0.0498 and 0.0244 ?g·g-1,respectively.The results show the ratio of inorganic species and total selenium in Panax notoginseng was 54.5%.The recoveries of four selenium species ranged from 95.4%to 114.6%.3.Selenium speciation in Radix Puerariae has been developed using magnetite solid phase extraction(MSPE)coupled HPLC-ICP-MS.The Fe3O4 magnetic nanoparticles were prepared by coprecipitation method with the ammonia as precipitant.5-sulfosalicylic acid was grafted on the surface of the Fe3O4@SiO2,thereby magnetite nanoparticles were functionalized by sulfonic acid groups(SSMNPs).The detection limit of this method for SeCys2,Se(?),SeMet and Se(?)was 0.0065,0.005,0.023 and 0.018 ng·mL-1,respectively.The linear range was 0.0140-100 ng·mL-1,and the correlation coefficients were more than 0.9997.The relative standard deviation(RSD)of method was less than 3%.The recoveries were ranged from 89.8%and 101.9%.