Atomic Spectroscopy Basics (2012)
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This document provides an introduction to various spectroscopy techniques including absorption spectroscopy, emission spectroscopy, and mass spectrometry. It then discusses specific techniques like atomic absorption spectroscopy (AAS), flame emission spectroscopy (FES), and inductively coupled plasma atomic emission spectroscopy (ICP-AES). The key components, working principles, and applications of these techniques are described. Sample preparation procedures including drying, grinding, and acid digestion are also outlined. Finally, quality control procedures like replicates, spikes, and standard reference materials are mentioned.
Atomic Spectroscopy Basics (2012)
- 1. Vasiliy V. Rosen, M.Sc., ZBM Analytical Laboratory icpaes@gmail.com, www.rosen.r8.org 2012
- 2. INTRODUCTION ספקטרוסקופיה בליעה ספקטרוסקופיה פליטה Absorption Spectroscopy: Emission Spectroscopy: AAS FES, ICP-AES(OES) ספקטרוסקופיה מסה Mass Spectrometry
- 3. INTRODUCTION Ion Emission Atom Emission E – energy difference between two levels; h – Plank’s constant, 6.626068 × 10-34 m2kg/s; c – speed of light, 299 792 458 m/s; λ – wavelenght, nm
- 4. INTRODUCTION Nebulizer converts the solution into a spray Flame (or Plasma) causes the solvent to evaporate, leaving dry aerosol particles, then volatilizes the particles, producing atomic, molecular and ionic species
- 5. SAMPLE PREPARATION Process Goal Problems Drying Sample stabilization, Thermal homogenization and decomposition and accurate weighing reduction in dry facilitation weight Grinding Sample homogenization, Pollution by metals organic matter reduction from the mill parts facilitation Dry or Wet Acid Organic matter destruction, Analyte loss, Digestion solid material dissolution contamination, not complete solid dissolution
- 6. SAMPLE PREPARATION EQUIPMENT Microwave-assisted Digestion Hot Plate Digestion Block Most samples have to be prepared for analysis on ICP, FF and AA. Solid samples are solubilized. Organic matter is "mineralized" i.e. converted to inorganic compounds.
- 7. SAMPLE PREPARATION EQUIPMENT Microwave Laboratory Oven “Ethos One” and Teflon vessels
- 8. SAMPLE PREPARATION EQUIPMENT “Ethos One”: Temperature and Pressure control
- 9. SAMPLE PREPARATION EQUIPMENT “Ethos One”: “Vent-and-Reseal” technology
- 10. SAMPLE PREPARATION EQUIPMENT 6 samples 250 1200 1000 Temperature (°C) 200 Power (watt) 800 150 600 100 400 50 200 0 0 0.00 0.05 0.10 0.15 0.20 0.25 Time (minutes) “Ethos One”: Digestion profile
- 11. MATRIX Cd, 1 mg/L, in weak acid Cd, 1 mg/L, in base Analyte concentrations are equal, but intensities are different 11
- 12. MATRIX The elements that are stable/soluble in HNO3
- 13. MATRIX The elements that are stable/soluble in HCl
- 14. MATRIX The elements that are stable/soluble in H2SO4
- 15. MATRIX HNO3 HCl H2SO4
- 16. QC PROCEDURES Replicates – method precision * evaluation. Spike – addition of the known concentration of analyte to the sample at the preparation step. The evaluation of the preparation quality and matrix effect. Matrix matching – preparation of the calibration standards in the same matrix as the samples. Internal standard – addition of the element that sample does not contain (Y, Sc) in known concentration. The evaluation of the matrix effect. Standard Reference Material preparation and analysis for method accuracy ** evaluation. *Precision is how close the measured values are to each other. **Accuracy is how close a measured value is to the actual (true) value.
- 17. QC PROCEDURES SRM 1570a Spinach Leaves Elemental Analysis Method precision Method accuracy
- 18. FLAME EMISSION SPECTROSCOPY (FES) Propane-butane flame ( 2000 – 3000 º C); Optical filter is used to monitor for the selected emission wavelength produced by the analyte; Suitable for elements with low excitation energy (Na, K, Li, Rb, Cs and Ca).
- 19. FLAME EMISSION SPECTROSCOPY (FES) Optic Filter Flame Data Display Nebulizer Flame Photometer M-410 (Sherwood Scientific, UK)
- 20. FLAME EMISSION SPECTROSCOPY (FES)
- 21. FLAME EMISSION SPECTROSCOPY (FES)
- 22. ATOMIC ABSORPTION SPECTROSCOPY (AAS) Gases mixture flame (1800 – 4500 º C): air-propane, air-acetylene etc. ; Atomic absorption spectrometry quantifies the absorption of ground state atoms in the gaseous state ; The atoms absorb ultraviolet or visible light and make transitions to higher electronic energy levels . The analyte concentration is determined from the amount of absorption.
- 23. ATOMIC ABSORPTION SPECTROSCOPY (AAS) Operation principle of AAS Light source – hollow cathode lamp. Each element has its own unique lamp. Atomic cell – flame (gas mixture) or graphite furnace (accepts solutions, slurries, or even solids). Detector – photomultiplier.
- 24. ATOMIC ABSORPTION SPECTROSCOPY (AAS)
- 25. ATOMIC EMISSION SPECTROSCOPY ICP-AES Inductively Coupled Plasma - Atomic Emission Spectrometry
- 26. ICP-AES Basics Atomic emission spectroscopy measures the intensity of light emitted by atoms or ions of the elements of interest at specific wavelengths; Inductively Coupled Plasma spectrometers use emission spectroscopy to detect and quantify elements in a sample; ICP-AES uses the argon plasma (6000-10000º C) for atomization and excitation of the sample atoms; ICP-AES determines approximately all of the elements except gases and some non-metals (C, N, F, O, H).
- 28. Schematic diagram of the processes in the ICP
- 29. ICP SPECTROMETER Main Systems
- 30. ICP-AES: SAMPLE INTRODUCTION SYSTEM Torch with Plasma Nebulizer (cross-flow) Spray Chamber To Waste Sample Solution Entrance Argon Supply
- 31. ICP-AES: NEBULIZER Cross-flow nebulizer Modified-Lichte nebulizer Burgener nebulizer
- 32. ICP-AES: NEBULIZER aerosol
- 33. ICP-AES: NEBULIZER Modified Lichte Nebulizer aerosol
- 34. ICP-AES: NEBULIZER aerosol
- 35. ICP-AES: TORCH Auxiliary Argon Flow Coolant Argon Flow Nebulizer Argon Flow
- 36. ICP-AES: TORCH
- 37. ICP-AES: PLASMA Inductively Coupled Plasma Source A plasma is a hot, partially ionized gas. It contains relatively high concentrations of ions and electrons. Argon ions, once formed in a plasma, are capable of absorbing sufficient power from an external source to maintain the temperature at a level at which further ionization sustains the plasma indefinitely. The plasma temperature is about 10 000 K.
- 38. ICP-AES: PLASMA Inductively Coupled Plasma Source
- 39. ICP-AES: RADIAL (SOP) AND AXIAL (EOP)
- 40. ICP-AES: RADIAL (SOP) AND AXIAL (EOP) SOP: Side-on-Plasma EOP: End-on-Plasma more suitable for hard matrices (concentrated samples); more suitable for light matrices; alkali metals (Na, K, Li) calibration is more linear; alkali metals (Na, K, Li) calibration is less linear; less spectral interferences; more spectral interferences; lower sensitivity (Limit-of-Detection is higher); higher sensitivity (Limit-of-Detection is lower);
- 41. ICP-AES: OPTICS
- 42. ICP-AES: OPTICS
- 43. ICP-AES: BACKGROUND CORRECTION Background Correction Background Correction Position 1 Position 2 Linear Function Approximation
- 44. ICP-AES: BACKGROUND CORRECTION Linear Function Approximation Polynomial Function Approximation
- 45. ICP-AES: SPECTRAL INTERFERENCES Sulfur in plant sample Boron in plant sample Boron in plant sample Boron in standard Sulfur in standard (1 mg/L) (10 mg/L) Sulfur spectral interference on Boron line 182.6 nm
- 46. ICP-AES: SPECTRAL INTERFERENCES Fe 25 ppm Iron spectral interference on B 0.1 ppm Boron lines 249.7 and 208.8 nm Fe 25 ppm
- 47. ICP-AES: SPECTRAL INTERFERENCES Manganese spectral interference on Gold lines 242.7 mn Mn 10 ppm Numerical Data Au 1 ppm
- 49. ICP-MS: BASICS Shadow stop blocks the photons (+) (+) (+) (+) Electrostatic lens focuses the beam into the slit Cones sample the center portion of the ion beam
- 50. ICP-MS: BASICS Quadropole mass filter can separate up to 2400 amu (atomic mass units) per second by switching alternating voltages applied to opposite pairs of the rod
- 51. ICP-MS: BASICS
- 52. ICP-MS: BASICS
- 53. ICP-MS: BASICS
- 54. ICP-AES (MS), FES AND AAS: APPLICATION Clinical Analysis: metals in biological fluids (blood, urine); Environmental Analysis: trace metals and other elements in waters, soils, plants, composts and sludges; Pharmaceuticals: traces of catalysts used; traces of poison metals (Cd, Pb etc); Industry: trace metal analysis in raw materials; noble metals determination. Forensic science: gunshot powder residue analysis, toxicological examination ( e.g., thallium (Tl) determination)
- 55. ZBM LABORATORY WEBSITE http://departments.agri.huji.ac.il/zabam/