How Does an ICP-MS Work?

Inductively coupled plasma mass spectrometry (ICP-MS) is a technique used to identify the elements present in a sample, unlike LC/MS and GC/MS, which measure molecules and compounds. In ICP-MS, an argon plasma (the ICP) is used to ionize the sample, and the ions are then analyzed with a mass spectrometer. This method offers exceptionally low detection limits for nearly all the elements it can detect.

What Steps are Involved in ICP-MS Analysis?

1. Choose the Right Configuration

Before diving into analysis, it's crucial to select the appropriate hardware setup. This selection relies heavily on the sample type and the analysis specifications. Additionally, ensure adherence to any standard operating procedures or industry regulations.

2. Conduct Essential Maintenance

Prior to using the instrument, confirm that all necessary maintenance tasks have been completed. This ensures the equipment functions optimally and produces reliable results.

3. Prepare Samples

Sample preparation is a critical step and comes with varying complexity:

• Water samples: Typically involve simple acidification.
• Solid samples: May require complex procedures like digestion with acids, fusion, or solubilization with organic solvents.

Key considerations for preparation include:

• Total Dissolved Solids (TDS): Understanding the inorganic content helps decide the dilution and instrument settings.
• Analyte Stability: Certain analytes require specific acids or solvents to maintain stability. For instance, mercury needs hydrochloric acid to remain stable.
• Element Concentration: Prepare calibration standards that match the expected range of concentrations.
• Acids and Solvents: The presence and concentration of acids and solvents in samples can necessitate particular sample introduction systems.
• Particulates: Filtering or centrifuging samples might be necessary to prevent instrument blockages.

4. Optimize Instrument Performance

Start the instrument and carry out optimization procedures or performance checks, which may be automated depending on the system. These checks ensure the equipment is ready for analysis.

5. Method Configuration

Set up the analysis method by choosing the isotope masses for measurement and applying internal standards to adjust for signal variances. Define necessary parameters like integration times, uptake and rinse durations, and select modes for gas interactions. For routine methods, template methods may be available to simplify this process.

6. Organize Sample Analysis

Prepare a sequence or batch list outlining run order and positions for each sample. This organization includes calibrations for each analyte and ensures quality control by incorporating blank and QC checks. For routine analyses, much of this might be predefined.

7. Quality Control and Reporting

Post-analysis, verifying QC results is essential. This validation can occur manually, automatically through software, or via a laboratory information management system (LIMS). In some cases, real-time QC checks necessitate recalibration or sample reruns to ensure data integrity.

By carefully following these steps, laboratories can effectively conduct ICP-MS analysis, ensuring consistent and accurate results.

Common Applications for ICP-MS

ICP-MS analysis is used in nearly every industry from routine environmental monitoring, consumer product testing, food and pharmaceutical safety applications, through life science and clinical research, mining and metals analysis, and more. It can measure nearly all naturally occurring elements as well as many non-natural “radiogenic” isotopes. The elements that cannot be measured are H and He (which are below the mass range of the mass spectrometer), Ar, N, and O (which are present at high level from the plasma and air), and F and Ne (which can’t be ionized in an argon plasma).

What Types of Samples Can Be Analyzed Using ICP-MS?

Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is a powerful and flexible analytical technique capable of handling a wide variety of sample types. Its primary function is to analyze liquid samples—like water—but its versatility extends far beyond that.

• Liquid Samples: Ideal for analyzing liquids and those samples that can be dissolved or acid digested to form a liquid solution.

• Organic Solvents: ICP-MS effectively measures organic solvents, making it a versatile choice for various research fields.

• Nanoparticles: Its sensitivity allows it to detect extremely small particles, including those at the nanoscale.

• Direct Analysis: By connecting to specialized accessories, ICP-MS can directly analyze solid materials and gases, bypassing the need for complex preparatory steps.

• Chromatographic Coupling: When paired with chromatographic separation devices like HPLC (High-Performance Liquid Chromatography), IC (Ion Chromatography), GC (Gas Chromatography), CE (Capillary Electrophoresis), or FFF (Field Flow Fractionation), ICP-MS provides detailed insights into the different chemical species present within a sample.

ICP-MS's adaptability and sensitivity make it an indispensable tool for researchers and analysts working across diverse scientific disciplines, unraveling complex chemical compositions in virtually any sample form.

Sample Tubes for ICP-MS

Although borosilicate glass vials are common for chromatography applications, plastic tubes are used for ICP-MS applications. This is common practice because some metals can easily absorb into glass, but not into plastics. At Chrom Tech, we offer virgin polypropylene autosampler tubes and caps for AA, ICP-MS, ICP-OES, TOC, UV-VIS, HPLC, FIA, GPC, fraction collection and liquid handling applications. These ICP-MS tubes are standard sizes and are used by many instrument manufacturers including Agilent, Lachat, Leeman Labs, Perkin Elmer, and more. For a fraction of the price, we offer the same excellent clarity and resistance to acids as the leading manufacturers making our tubes a great choice for ICP-MS applications.

When conducting ICP-MS analysis, there are several ways to verify quality control (QC) results. During the analysis, users often review QC outcomes before finalizing the report. This crucial step helps ensure accuracy and reliability.

Methods for QC Verification:

1. Automated Systems: Many professionals leverage built-in software features that automatically flag potential issues, allowing for prompt detection and correction. This automation streamlines the QC process, saving valuable time.

2. Manual Checks: Alternatively, some users opt to manually review results using laboratory information management systems (LIMS). These offline evaluations provide an extra layer of scrutiny.

3. Regulatory Compliance: For certain methods governed by regulations, performing QC checks mid-run is mandatory. If any discrepancies are discovered, predefined actions—such as recalibrating the instrument, rinsing components, or repeating the sample measurement—are necessary to ensure data integrity.

QC results in ICP-MS analysis are assessed through a combination of automated software checks, manual reviews, and specific regulatory protocols designed to uphold analysis standards.

Conclusion

ICP-MS is a powerful and highly versatile technique that plays a vital role in various scientific fields, from environmental analysis to pharmaceutical testing. Its ability to detect a wide range of elements and analyze different types of samples makes it an invaluable tool for researchers and professionals.

By following a thorough process—from careful sample preparation to rigorous quality control—laboratories can ensure accurate and reliable results. As the technology continues to advance, ICP-MS will remain a key instrument, meeting the evolving needs of modern analytical chemistry with precision and efficiency.