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

尽管ICP-MS具有诸多优势，但准确的元素分析仍会受到光谱干扰和非光谱干扰的影响。
光谱干扰是由与分析物离子具有相同 m/z 值的离子引起的。干扰物包括同量异位素、多原子离子和难熔氧化物离子。
同量异位素干扰源于分析物的同量异位素，即具有相同质量数的不同核素——这意味着其 m/z 值相同。
多原子离子干扰是由于等离子体中的组分与基质或大气中的组分结合，形成多原子物种，这些多原子物种进一步碎裂成与待测物具有相同 m/z 值的分子离子所致。
由于分析物和基体物质形成难熔的氧化物和氢氧化物，从而产生严重的干扰。
非光谱干扰包括基体效应，该效应与基体成分的高浓度有关，通常会导致分析物信号降低。
通过使用适当的标准内参，可以很大程度上补偿基质效应。

电感耦合等离子体质谱 (icp-ms)：干扰

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

电感耦合等离子体质谱 (ICP-MS) 是一种用来精确元素分析的具有高选择性和灵敏性的技术。尽管 ICP-MS 质谱的分析相对简单，但它会受到光谱和非光谱等干扰所产生的影响。当等离子体中含有 m/z 值或与分析物离子相同的离子时，便会出现光谱干扰。光谱干扰可以分为同量异位干扰、多原子离子干扰和难熔氧离子干扰。

当感应耦合等离子体中含有相同质量的异位分析物时，便会发生同量异位干扰。这些物质是具有相同质量数的不同核素，因此在假设电荷相同的情况下，与分析物会具有相同的 m/z 值。例如，40Ar+ 和 58Fe+ 通常分别与 40Ca+ 和 58Ni+ 的峰发生重叠。基于四极杆质量仪器的分辨率小于 1 u，其中同量异位素所产生的干扰在很大程度上影响了仪器分辨率。然而，可以使用更高分辨率的仪器将其最小化。

当各种等离子体中的成分与基质或大气成分发生相互作用形成多原子物质时，便能够观察到另一种光谱所产生的干扰，该多原子物质能够通过进一步分裂形成与分析物离子具有相同 m/z 值的分子离子。其中的 40ArH+、16O2+ 和 40ArO+ 便是一些潜在的干扰物。通过空白校正或使用不同的分析物同位素便可以消除此类干扰。

当多种分析物和基质中的成分能够形成氧化物和氢氧化物，并且其中的峰与分析物的离子发生重叠时，便会出现另一种严重的干扰。氧化物和氢氧化物的形成取决于各种实验因素，例如注射器的流量、样品孔的尺寸、取样器与撇渣器的间距等。这些干扰比同量异位离子和多原子离子所产生的干扰更难消除。

非光谱干扰主要包括基体效应。它与高浓度的基质物质（通常为 500 至 1000 mg/mL）是相关的，从而会导致分析物的信号减弱。特定的实验条件增强了分析物的信号。通过加入质量和电离势这类测量值，便能够通过接近分析物的内标来消除基质所产生的干扰。

电感耦合等离子体质谱 (ICP-MS)：干扰

尽管ICP-MS具有诸多优势，但准确的元素分析仍会受到光谱干扰和非光谱干扰的影响。

inductively-coupled-plasma-mass-spectrometry-icp-ms-interferences

Education

教育

JoVE Core

Analytical Chemistry

分析化学

Unit 1

第一单元

Principles of Mass Spectrometry

质谱分析原理

KEY TERMS AND CONCEPTS

关键术语与概念

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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Mass Accuracy in HRMS Analysis

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inductively coupled plasma&#8211;mass spectrometry (icp&#8211;ms): overview

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ICP-MS Sample Ionization and Detection

ICP-MS uses an inductively coupled plasma torch to turn samples into ions for mass analysis. Solid samples are first dissolved and volatilized before they enter the hot argon plasma. Solution samples are nebulized, which means they are converted into a fine spray, and then passed through the same plasma. Inside the plasma, the analytes break apart. Their atoms become positively charged ions, along with some molecular species. These positive ions are sent to the mass spectrometer, where they...

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

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

analytical chemistry

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ICP-MS Signal Interference Sources and Fixes

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