Name: icp-ms signal interference sources and fixes
Uploaded: 2024-04-04T10:51:35.000Z
Duration: 1 min 20 s
Channel: JoVE

Despite the advantages offered by ICP&#8211;MS, accurate elemental analysis is affected by spectroscopic and non-spectroscopic interferences.
Spectroscopic interference is caused by ions with the same m/z values as analyte ions. Interfering species include isobaric species, polyatomic ions, and refractory oxide ions.
Isobaric interference arises from analyte isobars, which are different nuclides that have the same mass number&#8212;meaning the m/z values are the same.
Polyatomic ion interference results from the combination of plasma species with matrix or atmospheric species to form polyatomic species which further fragment into molecular ions of the same m/z value as an analyte.
A critical interference arises due to the formation of refractory oxide and hydroxide species from the analyte and matrix species.&#160;&#160;
Non-spectroscopic interference includes the matrix effect, which is associated with a high concentration of matrix species and generally causes analyte signal reduction.
Matrix effects can be largely compensated for by using an appropriate internal standard.

inductively coupled plasma-mass spectrometry (icp-ms): interferences

Inductively Coupled Plasma-Mass Spectrometry (ICP-MS): Interferences

Inductively coupled plasma&#8211;mass spectrometry (ICP&#8211;MS) is a highly selective and sensitive technique for accurate elemental analysis. Though the analysis of ICP&#8211;MS mass spectra is comparatively straightforward, it is affected by spectroscopic and non-spectroscopic interferences. Spectroscopic interferences arise when the plasma contains ionic species with an m/z value the same as the analyte ion. Spectroscopic interference can be categorized as isobaric, polyatomic ions, and refractory oxide ion interferences.
Isobaric interference occurs when the inductively-coupled plasma contains isobaric species of analytes. These species are different nuclides with the same mass number and so have the same m/z values as the analyte, assuming the same charge. For example, 40Ar+ and 58Fe+ generally overlap the peaks for 40Ca+ and 58Ni+, respectively. Quadrupole-based mass instruments, having a resolution of less than 1 u, are substantially affected by isobaric interference. However, it can be minimized using higher resolution instruments.
Another spectroscopic interference is observed when various plasma components interact with matrix or atmospheric components to form polyatomic species, which may undergo further fragmentation to form molecular ions having the same m/z value as the analyte ion. 40ArH+, 16O2+, and 40ArO+ are some potential interferents. A blank correction or using a different analyte isotope removes such interferences.
Another critical interference occurs when several analyte and matrix components form oxides and hydroxides whose peaks overlap with the analyte ions. The formation of oxides and hydroxides depends on various experimental factors, like the injector flow rate, the sample orifice size, the sampler skimmer spacing, etc. These interferences are more challenging to eliminate than isobaric and polyatomic ion interferences.
Non-spectroscopic interferences mainly include the matrix effect. It is associated with a high concentration of matrix species&#8212;generally, 500 to 1000 mg/mL&#8212;causing analyte signal reduction. Specific experimental conditions enhance the analyte signal. Matrix interferences can be eliminated by incorporating an internal standard with mass and ionization potential close to the analyte.

Despite the advantages offered by ICP&#8211;MS, accurate elemental analysis is affected by spectroscopic and non-spectroscopic interferences.
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inductively-coupled-plasma-mass-spectrometry-icp-ms-interferences

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Analytical Chemistry

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Principles of Mass Spectrometry

KEY TERMS AND CONCEPTS

icp-ms signal interference sources and fixes

Inductively coupled plasma-mass spectrometry (ICP-MS) is a sensitive method for elemental analysis, but its spectra can be affected by interferences. These interferences can make the mass signal less accurate, even when the instrument is working well.

Spectroscopic interferences happen when ions in the plasma have the same mass-to-charge ratio, or m/z, as the analyte ion. This group includes isobaric interferences, polyatomic ion interferences, and refractory oxide ion interferences. Isobaric interference occurs when different nuclides share the same mass number and therefore the same m/z value if the charge is the same. For example, 40 Ar+ can overlap with 40 Ca+, and 58 Fe+ can overlap with 58 Ni+.

Quadrupole-based mass instruments, which have a resolution of less than 1 u, are strongly affected by isobaric interference. Using a higher-resolution instrument can help reduce this problem. Polyatomic interferences can appear when plasma species react with matrix or atmospheric components to form molecular ions. Examples include 40 ArH+, 16 O2+, and 40 ArO+.

These polyatomic interferences can be reduced with a blank correction or by choosing a different analyte isotope. Another important spectroscopic problem is the formation of oxides and hydroxides. These peaks can overlap with analyte ions. Their formation depends on experimental conditions such as injector flow rate, sample orifice size, and sampler-skimmer spacing. These interferences are often harder to remove than isobaric and polyatomic interferences.

Non-spectroscopic interferences mainly involve the matrix effect. A matrix is the other material in the sample, and a high matrix concentration of about 500 to 1000 mg/mL can reduce the analyte signal. Certain experimental conditions can improve the analyte signal. Matrix interference can also be reduced by using an internal standard with a mass and ionization potential close to the analyte.

ICP-MS Signal Interference Sources and Fixes

icp-ms-signal-interference-sources-and-fixes

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Inductively coupled plasma-mass spectrometry (ICP-MS) is a sensitive method for elemental analysis, but its spectra can be affected by interferences. These interferences can make the mass signal less accurate, even when the instrument is working well. Spectroscopic interferences happen when ions in the plasma have the same mass-to-charge ratio, or m/z, as the analyte ion. This group includes isobaric interferences, polyatomic ion interferences, and refractory oxide ion interferences. Isobaric...

key terms and concepts

Learn how ICP-MS signals can be affected by isobaric, polyatomic, oxide, and matrix interferences, and how blank correction and internal standards help.

ICP-MS Signal Interference Sources and Fixes | JoVE K12

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ICP-MS Signal Interference Sources and Fixes

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