Study On The Protein And Element Speciation Using Capillery Electrophoresis Coupled With Inorganic Mass Spectrometry

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.Capillary electrophoresis（CE）has many advantages such as high separation efficiency,fast analysis,more analysis modes,less reagent usage,wide application range and easy automation,etc.It has become one of the most important analytical methods for the composition analysis in complex systems.CE coupled with ICP-MS has greatly improved in sensitivity,accuracy,and analysis speed.CE-ICP-MS has opened up a new field in trace element speciation analysis,metal complex analysis,medicine,biology,environment and so on,and also provided a powerful method for elemental morphological analysis of complex samples analysis means.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.Magnesium and iron elements are essential elements of the human body and play a vital role in human life activities.However,once magnesium and iron lose balance in the body,they will cause metabolic disorders and even disorders.Diabetes with certain diseases also have a close relationship with hypomagnesemia and iron overload.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,the research has been carried on foundation of capillary electrophoresis coupled with inductively coupled plasma mass spectrometry and this application to human serum albumin,elemental speciation in plasma of healthy human and type 2 diabetes human,and selenium speciation in selenium-enriched foods.The main contents and results were shown as follows:1.A new method for interaction of cobalt ion and HSA has been developed by capillary electrophoresis coupled with inductively coupled plasma mass spectrometry（CE-ICP-MS）.Under the best conditions of experimental,the morphological peaks of free cobalt and Co（HSA）²⁺after interaction between Co（II）and HSA were obtained.The strong binding site（n₁）and binding constant（K₁）of Co（II）-HSA are 3.68 and 3.95×10⁴ L/mol,respectively.The weak binding site（n₂）and binding constant（K₂）of Co（II）-HSA are 13.72 and 1.86×10⁴L/mol,respectively.This method is rapid,simple and accurate for studying the interaction of metal ions and HSA.2.A novel method for determination of magnesium and iron speciation in plasma samples from healthy human and type 2 diabetes patients was developed by capillary electrophoresis coupled with inductively coupled plasma mass spectrometry（CE-ICP-MS）.Under the best conditions of experimental,The ten forms of magnesium speciation and four forms of iron speciation were gained in healthy human plasma samples.And the eight forms of magnesium speciation and fives forms of iron speciation were gained in type 2 diabetes patients plasma samples.Diabetic patients have lower levels of magnesium in plasma than the healthy people,however iron levels are significantly higher than the healthy people.The RSDs of migration time and concentration of magnesium and iron speciation for eleven replications were less than 4.0%.3.A new method for the determination of six selenium species in selenium-enriched watermelon by capillary electrophoresis coupled with inductively coupled plasma mass spectrometry（CE-ICP-MS）was established.Separation of selenium species in selenium-enriched watermelon with pepsin as extractant was carried out by ultrasonic.Six selenium species could be completely separated within 11 min under the condition of 8 mmol/L NaH₂PO₄-12 mmol/L H₃BO₃-0.2 mmol/L CTAB pH 9.2 as buffer solution after were extractant with graphite-like phase carbon nitride（g-C₃N₄）enrichment and eluted with NaOH.The established method is simple,rapid and sensitive.The linear correlation coefficients of all the selenium species in the mass spectrometry with CH₄ dynamic response model to eliminate interference are all greater than 0.9995.Under the optimal conditions,the limits of detection（3σ）for SeUr,SeCys₂,SeMet,Se（IV）,Se（VI）and SeEt were observed as 6.2,30,11,8.2,48and 5.5 ng/L,respectively.The recoveries were in the range of 97.1%to 105%and the RSDs（n=5）of recoveries were less than 3%.The method was applied to the analysis of selenium in Se-enriched watermelon with satisfactory results.