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ICP-MS (Inductively coupled plasma mass spectrometry )
Inductively Coupled Plasma Spectroscopy (ICP-OES/MS)
In plasma emission spectroscopy (OES), a sample solution is introduced into the core of inductively coupled argon plasma (ICP), which generates temperature of approximately 8000°C. At this temperature all elements become thermally excited and emit light at their characteristic wavelengths. This light is collected by the spectrometer and passes through a diffraction grating that serves to resolve the light into a spectrum of its constituent wavelengths. Within the spectrometer, this diffracted light is then collected by wavelength and amplified to yield an intensity measurement that can be converted to an elemental concentration by comparison with calibration standards.
In plasma mass spectroscopy (MS), the inductively coupled argon plasma (ICP) is once again used as an excitation source for the elements of interest. However in contrast to OES, the plasma in ICP-MS is used to generate ions that are then introduced to the mass analyzer. These ions are then separated and collected according to their mass to charge ratios. The constituents of an unknown sample can then be identified and measured. ICP-MS offers extremely high sensitivity to a wide range of elements.
ICP-OES/MS
Technical Capabilities
Signal Detected:
Photons (OES) or Ions (MS)
Elements Detected:
Up to 70 elements
Detection Limits:
ppb
Depth Resolution:
Bulk technique
Imaging/Mapping:
No
Ideal Uses for ICP-OES/MS Analysis
- Bulk quantitative survey analysis of major, minor or trace constituents
- High accuracy determinations of major and minor constituents in a wide range of materials
- Quality and process control
Relevant Industries for ICP-OES/MS Analysis
- Aerospace
- Sputter targets
- Chemicals
- Alloy producers
- Food/beverage
- Geological
- Pharmaceutical
- environmental water, wastewater, processing water
Strengths of ICP-OES/MS Analysis
- Many elements (up to 70 in theory) can be determined simultaneously in a single sample analysis.
- The useful working range is over several orders of magnitude.
- Instrumentation is suitable to automation, thus enhancing accuracy, precision and throughput.
- The combination of ICP OES and MS techniques is very powerful for determining an extremely wide range of elements from major components to very low detection limits (typically sub ppb) with high accuracy and precision.
Limitations of ICP-OES/MS Analysis
- The emission spectra are complex and inter-element interferences are possible if the wavelength of the element of interest is very close to that of another element.
- In MS the common matrix elements and other molecular species can interfere with the determination of some elements. Some doubly charged or molecular ionic species create difficulties in quantifications.
- The sample to be analyzed must be digested prior to analysis in order to dissolve the element(s) of interest.