Ce icp-ms

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Ce icp-ms

  1. 1. Hyphenated Technique of Capillary Electrophoresis and Inductively Coupled Plasma Mass spectrometry Jesús Anzano University of Zaragoza– Department of Analytical Chemistry Zaragoza
  2. 2. <ul><li>Introduction: </li></ul><ul><li>a. Elemental Speciation </li></ul><ul><li>b. Capillary Electrophoresis (CE) </li></ul><ul><li>c. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) </li></ul><ul><li>CE-ICP-MS Hyphenated System </li></ul><ul><li>a. CE-ICP-MS Instrument Setup </li></ul><ul><li>b. Interface and Modified Nebulizer Design </li></ul><ul><li>c. Direct Injection Interface design </li></ul><ul><li>d. Pulsed Field Capillary Electrophoresis </li></ul><ul><li>e. Laminar Flow Effect </li></ul><ul><li>Elemental Speciation Analysis application </li></ul><ul><li>a. Chemical forms of As and Cr in preservative wood </li></ul><ul><li>b. Leaching effect of As and Cr in surround soil </li></ul><ul><li>Preliminary Results </li></ul>Outline
  3. 3. Elemental Speciation <ul><li>Elemental Speciation is the identification and quantification of the chemical form of an element. </li></ul><ul><li>The toxicological, physiological and biological effects are species dependent. </li></ul><ul><li>Main area : </li></ul><ul><li>---Environmental area </li></ul><ul><li>---Food area </li></ul><ul><li>---Health area </li></ul>
  4. 4. Capillary Electrophoresis (CE) <ul><li>Separate mixture of ionic species quickly </li></ul><ul><li>Good resolution and separation efficiency </li></ul><ul><li>Simple instrument set-up </li></ul><ul><li>Relative low cost </li></ul><ul><li>Require much less sample </li></ul>
  5. 5. Inductively Coupled Plasma Mass spectrometry (ICP-MS) <ul><li>Direct element information and quantification </li></ul><ul><li>Species identification via migration time </li></ul><ul><li>Low detection limit </li></ul><ul><li>High sensitivity and selectively </li></ul>
  6. 6. CE-ICP-MS Instrument Setup Quadrupole Mass Analyzer Detector Computer ICP Interface UV Detector Buffer / Sample Make-up Solution Capillary CE HV Power Supply
  7. 7. The CE-ICP-MS Interface Requirements: An electrical connection to the end of CE capillary High aerosol transport efficiency Low dead volume ICP Nebulizer Flow From CE Capillary CE Platinum Ground Electrode Make-up Sheath Flow O-ring
  8. 8. The Modified Concentric Nebulizer Nebulizer Gas In CE Capillary Stainless Steel Tube To Spray Chamber CE Capillary Stainless Steel Tube Nebulizer Inner Tube
  9. 9. The Concentric Nebulizer and Interface <ul><li>Advantages: </li></ul><ul><li>- Universally applicable </li></ul><ul><li>- Easy to install and remove </li></ul><ul><li>- Inexpensive </li></ul><ul><li>Disadvantages: </li></ul><ul><li>- Sample solution from CE is diluted and causes losses in sensitivity. </li></ul><ul><li>- Increase sample solution flow rate may decrease CE resolution. </li></ul><ul><li>- Decrease make-up sheath flow rate may decrease ICP-MS aerosol transfer efficiency </li></ul>
  10. 10. The Direct Injection Interface Nebulizer Gas Platinum Electrode CE Capillary Nebulizer Body ICP Torch Sampler Cone
  11. 11. The Direct Injection Interface <ul><li>Advantages: </li></ul><ul><li>- Improve precision. </li></ul><ul><li>- Reduce rinse-out time. </li></ul><ul><li>- Low absolute detection limit. </li></ul><ul><li>- Reduce peak broadening due to the low dead volume. </li></ul><ul><li>Disadvantages: </li></ul><ul><li>- ICP-MS plasma may be extinguished. </li></ul><ul><li>- High cost. </li></ul><ul><li>- Difficult to use. </li></ul>
  12. 12. Pulsed Field CE-ICP-MS Instrument Setup V A Sample or Buffer UV Detector Current Voltage Probe Pulse Power Supply Capillary Interface Nebulizer To ICP Capillary with Silver Paint + G
  13. 13. Pulsed Field CE-ICP-MS Comparison of power consideration for a continuous versus pulsed CE Continuous  s or ms, Pulsed DC 20kV, 40  A 0.8W Dc: 5kV, 10  A (0.05W) Pulse: 100kV, 0.2mA, 100  s, 200Hz (20W) Average: 0.45W t 1 t 2 Pulse DC
  14. 14. Pulsed Field CE-ICP-MS <ul><li>Theoretical plate number N=L 2 /  L 2 =(  ep +  eo )V/2D (1) </li></ul><ul><li>Resolution R s = N 1/2 (  v /  ) /4 (2) </li></ul><ul><li>Plate Height H heating =(  2 S 2  2 /  2 D)((K 1 E 5 r c 6 /  app ) </li></ul><ul><li>+ (K 2 E 6 r c 6 /LD)) (3) </li></ul><ul><li>Where V is the applied voltage, E is the electric field strength. </li></ul><ul><li>1. Kennedy, R. T.; German, I.; Thompson, J. E.; Witowski, S. R. Chem. Rev . 1999 , 99, 3081-3131. </li></ul>The effect of Joule heating on band broadening
  15. 15. Pulsed Field CE-ICP-MS <ul><li>Advantages: </li></ul><ul><li>- Reduce the Joule heating which causes band broadening in conventional CE. </li></ul><ul><li>- Large diameter capillary can be used to attain high flow rate. </li></ul><ul><li>- The interface is simpler and high sensitivity without dilution of the analyte. </li></ul><ul><li>Disadvantages: </li></ul><ul><li>- High cost. </li></ul>
  16. 16. Laminar Flow Effect in CE-ICP-MS Cross-Sectional Flow Profile Due to Electroosmotic Flow Cross-Sectional Flow Profile Due to Laminar Flow
  17. 17. Elemental Speciation Analysis Application <ul><li>Major consideration: </li></ul><ul><li>The toxicity of copper (Cu), chromium (Cr) and arsenic (As) is dependent on elemental species. </li></ul><ul><li>Preservative wood and soil sample Preparation. </li></ul><ul><li>The state of As and Cr on treated wood. </li></ul><ul><li>The effect of pH on leaching of As and Cr. </li></ul><ul><li>As and Cr leach from the treated wood into soil . </li></ul>The most widely used wood preservative is chromated copper arsenate (CCA)
  18. 18. Preliminary Result The concentric nebulizer and interface
  19. 19. The Configuration of Nebulizer Tip Design 1 Design 2 Design 3 Design 4 CE liquid flow Make-up buffer Torr seal
  20. 20. Modified Nebulizer Gas Flow Rate Effect
  21. 21. 0.0E+00 5.0E+05 1.0E+06 1.5E+06 2.0E+06 2.5E+06 3.0E+06 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 Make-up sheath flow rate (mL/min) 1ppm In signal (acps)/solution flow rate (mL/min) Make-up Sheath Flow Rate Effect

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