Inductively Coupled Plasma Mass Spectrometry (ICP-MS)

Recognized as one of the most important mass spectrometric techniques, Inductively Coupled Plasma Mass Spectrometry (ICP-MS) has multi-element capabilities for the characterization of samples in materials science. ICP-MS offers extremely high sensitivity (i.e. low detection limits) for a wide range of elements. Solid samples are generally dissolved or digested using a combination of acids in a closed microwave system, thus retaining potentially volatile analyte species. The resulting sample solution is then nebulized into the core of an inductively coupled argon plasma, where temperatures of approximately 9000 K are attained. At such high temperatures, the nebulized solution is vaporized, and the analyte species are atomized, and ionized. The ions generated in the high temperature argon plasma core are subsequently accelerated into a mass analyzer for both elemental and isotopic analysis. Intensity measurements are converted to elemental concentration by comparison with calibration standards. This technique is especially powerful for quantitative chemical analysis of high purity solids.

Ideal Uses of ICP-MS

Bulk quantitative analysis of major, minor and trace elements in solids and liquids
Precise and Accurate determination of major and minor elements in a wide range of materials
Quality control and process control, and research and development

Strengths

A range of elements (up to 70) can be measured in a single analysis
The useful linear dynamic range is over several orders of magnitude
The analysis can be automated, thus enhancing accuracy, precision and throughput
Dynamic Reaction Cell (DRC) technology virtually eliminates polyatomic isobaric interferences
The combination of ICP-OES and ICP-MS is very powerful for determining a wide range of elemental concentrations, from major components to very low levels (typically sub ppb) with high accuracy and precision

Limitations

The sample to be analyzed must be completely digested or dissolved prior to analysis
In mass spectral analysis, common matrix elements and other molecular polyatomic species can interfere with the measurement of some analytes
Multiply-charged or polyatomic species can create challenges in quantitation
Carbon, Nitrogen, Hydrogen, Oxygen, and halogens cannot be determined using these techniques

ICP-MS Technical Specifications

Signal Detected: Positive ions of stable isotopes (MS)
Sample Size Requirement: 250 mg to 1 gram of solid sample; typical solution volumes range from 1 – 10 mL
Elements Detected: Up to 70 elements
Typical Detection Limits: parts per billion in solution
Depth Resolution: Bulk analytical technique
Spatially Resolved Analysis: No
Imaging/Mapping: No