Module 18: ICP-MS and FES

• What does ICP-MS combine with to analyze samples?

  A high temperature ICP source and a mass spectrometer
• What is the role of the ICP source in ICP-MS?

  It converts the atoms of the elements in the sample to ions
• How are ions processed in ICP-MS after being created?

  They are separated and detected by the mass spectrometer
• What is a key feature of High Resolution ICP-MS (HR-ICP-MS)?

  It has high sensitivity for multi-element analysis down to pq/L
• What advantage does HR-ICP-MS have regarding interference components?

  It easily separates the element of interest from interfering components
• What is a straightforward analytical method used in HR-ICP-MS?

  In-situ analysis
• What is a notable feature of HR-ICP-MS regarding reactive gases?

  It does not use reactive gases for interference removal
• What are some applications of HR-ICP-MS?

  • Evaluate grade of mineral acids in semiconductor industry
  • Phosphorous detection in battery electrolyte
• Why is Inductively Coupled Plasma Mass Spectrometry (ICP-MS) widely used for trace metals analysis?


  Due to its sensitivity, wide range of elements, and relative freedom from interferences
• How many elements can ICP-MS detect at low concentrations?

  About 80 elements
• What concentration levels can ICP-MS detect?

  ppb and ppt levels with liquid samples
• What types of analysis can ICP-MS perform?

  Qualitative analysis, isotope ratio, semi-quantitative analysis, and quantitative analysis
• What is the principle behind the ICP source in ICP-MS?

  It is a plasma ionized by inductively heating gas with an electromagnetic coil
• What gas is used in the ICP source and what is its temperature?

  Argon (Ar) gas heated to a temperature greater than 6000 K
• How are solid samples prepared for ICP-MS?

  They are dissolved with acids in a closed microwave system
• What is the benefit of dissolving samples before analysis in ICP-MS?

  It reduces sample-specific matrix effects and potential for nebulizer blockage
• What types of acids can be used for sample digestion in ICP-MS?

  Strong acid or alkali
• What is a strength of ICP-MS regarding analysis speed?

  It can analyze 30 elements in 1 minute
• What is the detection limit range of ICP-MS?

  1. 100 pg/mL
• What does ICP-MS provide in terms of mass spectrum?

  A simple mass spectrum for qualitative analysis of each isotope
• What is the purpose of the quadrupole mass analyzer in ICP-MS?

  It separates ions based on their mass/charge (m/z) ratio
• How do the electric fields in the quadrupole mass analyzer function?

  Positive poles push lighter ions out, while negative poles hold lighter ions in
• What is the relationship between signal intensities and concentrations in ICP-MS?

  Signal intensities are directly proportional to the concentrations of the elements in the sample
• What are the limitations of ICP-MS?

  • Total dissolved solids (TDS) <0.1-0.2%
  • Only small fraction of samples introduced into plasma
  • Polyatomic interference
  • Isobaric interference
  • Matrix interference
• What is matrix interference in ICP-MS?

  It occurs when concomitant elements affect the signal of the target element
• What is the effect of heavy ions and light matrices on interference?

  Heavy ions with light matrices cause small interference
• What is the effect of light ions and heavy matrices on interference?

  Light ions with heavy matrices cause large interference
• What are the types of interferences in ICP-MS?

  • Polyatomic interference
  • Isobaric interference
  • Matrix interference
• Why is it necessary to select an appropriate solvent for each element in ICP-MS?

  To avoid interference from isotopes of one element overlapping with isotopes of another element
• What is the role of electron multipliers in ion detection?

  They amplify ions through secondary electron emission
• What is the maximum count rate modern SEM detectors can achieve?

  More than 10^9 ions/sec
• What is the process of ion extraction from plasma in ICP-MS?

  • Ions are extracted through a sampler cone and skimmer cone
  • The plasma passes through orifices before entering the mass spectrometer
• What is the structure of the ICP torch in ICP-MS?

  • Consists of a triple tube
  • Has a concentric circle made of quartz
• What is emitted by atoms after electronic excitation in flames?

  Electromagnetic radiation in the visible and ultraviolet regions
• What happens when metal ions are heated?


  They emit light measured by their wavelengths
• What are the strengths and limitations of flame emission spectroscopy?

  Strengths:

  • Can detect multiple metal ions in a sample
  • Very accurate
  • Very sensitive to tiny amounts
  • Very fast and can be automated

  
  

  Limitations:

  • Intensity is sensitive to flame temperature
  • Spectral interferences and self-absorption are common
• What is a common problem in flame emission spectroscopy?

  Spectral interferences and self-absorption
• How does flame emission spectroscopy compare to manual tests?


  Flame emission spectroscopy uses expensive machines and often gives better results
• What are the three main benefits of flame emission spectroscopy?

  Very accurate, very sensitive, and very fast
• What are the applications of flame emission spectrometry?


  • Determination of trace metals in solutions
  • Identification and quantification of elements in enzymes and metalloproteins
  • Clinical diagnosis of Na, K, Ca, and Mg in body fluids
  • Analysis of soils and fertilizers