Development Of Metal Coordination Compound Electrochemical Sensor Based On Ionic Liquid

Although trace elements are rarely present in the body,they are closely related to human life activities and are indispensable components of life activities,in particular,trace metal elements.Most of trace metal elements cann't be absorbed directly by the body,which usually exit as coordination compounds by chelating with organic ligands in the body.These coordination compounds play important physiological and biochemical functions such as bactericidal,antiviral and anticancer functions.As the close relationship between trace elements and human health,developing sensitive method to analyze these metal compounds is attracting the interest of analysts.In our studies,SW-ASV coupled with ionic liquids was used to detect ultratrace metal compounds in biological samples.This dissertation showed that the methods developed have high potential in the detection of ultra-trace metal compounds.Vitamin B₁₂ is selected as a representative analyte because of its low content in biological samples and its importance to human health.Hydrophobic[C₈mim][NTf₂]was chosen as the extraction solvent during LLE and also working as supporting electrolyte in the following SW-ASV.The widely electrochemical windows of[C₈mim][NTf₂]allow us directly depositing cobalt ions from vitamin B₁₂2 at a more negative potential.The conditions affecting the extraction efficiency and the parameters affecting the electrochemical response process were studied.The optimum conditions are as follow:for LLE,the KNO₃ concentration in solution 0.2mol L^-1,centrifugation time 4 min,centrifugal speed 8000 rpm;deposition potential-1.9 V and deposition time90 s was adopted during SW-ASV.The response current of vitamin B₁₂ showed a good linear in the concentration range from 0.1697 amol L^-1 to 16.97 amol L^-1.With a linear correlation coefficient R²=0.9982?n=3?,the regression equation was i_p?VB12???A?=3.324+0.5273C_?VB12?(amol L^-1),and the RSD is 1.437%for nine successive assays.The results showed that our method has good reproducibility and stability.Considering the sample volume is 10?L,the method can detect a single vitamin B₁₂.The method was applied to determine the content of vitamin B12 in the whole blood,The recoveries of vitamin B₁₂ were between 93.4%and 107.3%for spiked samples,which prove the accuracy of the proposed methodology.Sodium Copper Chlorophyllin capsule is widely used as an adjuvant for acute and chronic hepatitis and leukopenia treatment.Controlling its content is particularly important for pharmaceutical factories.This work developed a sensitive method for the determination of sodium copper chlorophyllin.[C₈mim][NTf₂]IL was selected as the extraction solvent,and the extractant of IL phase was directly analyzed in the following SW-ASV.Several factors affecting the efficiency of LLE have been optimized,such as the concentration of inorganic acid,centrifugal extraction time,and centrifugal extraction speed.The parameters of SW-ASV such as deposition time and deposition potential were also optimized.The optimum conditions for analyzing sodium copper chlorophyll are:HCl concentration of 0.6 mol L^-1,centrifugation time of 6min,centrifugation speed of 5000rpm,deposition potential of-1.2 V and deposition time of75 s.The response current of sodium copper chlorophyll showed a good linear relationship in the range 0.05 ng L^-15.00 ng L^-1.The linear equation was i_p?SCC???A?=8.118+1.279C_?SCC?(ng L^-1)and the correlation coefficient R² was 0.9921?n=3?,the RSD was 4.17%for nine successive assays and the detection limit was 3.441 pg L^-1?3S?.The method showed good reproducibility,stability and high sensitivity.The method was used to detect the concentration of sodium copper chlorophyll in sodium copper chlorophyll capsules,and the result agree with the marked value,proving the method is reliable.Chromium picolinate is the major active ingredient in some health foods and the amount in health foods play an important role in the efficiency of them.This work established a SW-ASV method for the direct determination the concentration of chromium picolinate in health foods.The 1-hexyl-3-methylimidazolium bistrifluoromethanesulfonylimide IL was chosen as the supporting electrolyte.The deposition time and deposition potential SW-ASV was optimized.The response current of chromium picolinate showed a good linear relationship in the concentration range from 10 nmol L^-1 to 1000 nmol L^-1.The linear equation was i_p?CrPic???A?=6.335+11.22C_?CrPic?(nmol L^-1)and the linear correlation coefficient R² was 0.9907?n=3?.The RSD was 8.01%for eight successive assays and the detection of limit was 5.496 nmol L^-1?3S?,showing the method had good reproducibility and stability.The method was used to detect the concentration of chromium picolinate in Gegen bitter melon chromium capsules.The results were consistent with the concentration of chromium picolinate labeled by the drug.