The Role of SP-ICP-MS in Environmental Analysis

Single-particle inductively coupled plasma–mass spectrometry (spICP-MS) has emerged as a tool for scientists monitoring the impact of nanomaterials on our ecosystems. As the production of engineered nanomaterials (ENMs) grows, so does the need for analytical techniques that can detect these particles at environmentally relevant concentrations.

In this Q&A overview, we explore the capabilities, applications, and future of this technology in environmental science.

How does spICP-MS differ from traditional ICP-MS when analyzing environmental samples?

Traditional ICP-MS is designed to measure dissolved elements, resulting in a steady-state signal as aerosols are continuously ionized in the plasma.¹ In contrast, spICP-MS treats individual particles as discrete events. When a single nanoparticle enters the plasma, it is vaporized and ionized, creating a burst of ions or an "ion cloud."^1,2 These clouds are detected as sharp, transient pulses.¹

This approach has one main advantage. It allows researchers to distinguish between dissolved ions and particulate matter without the need for laborious physical separation steps like ultrafiltration or chromatography.¹ This capability is vital for environmental matrices where both forms of an element often coexist.¹

What specific data can spICP-MS provide about particles in the environment?

The technique is uniquely capable of providing three critical metrics:

1. Particle Number Concentration: The number of detected pulses is directly proportional to the number of particles per milliliter in the original sample.^1,2
2. Particle Size and Distribution: The intensity of each pulse is proportional to the mass of the element in that specific particle. By assuming a particle’s shape (typically spherical) and knowing its density, scientists can convert this mass into a diameter to create a size distribution histogram.^1,2
3. Dissolved Concentration: The "background" signal between pulses represents the concentration of the element that has dissolved into the surrounding liquid.¹

Why is this technique preferred over other particle-sizing methods like dynamic light scattering (DLS)?

Although techniques like DLS or nanoparticle tracking analysis (NTA) are useful for pure samples, they often lack the elemental specificity required for complex environmental matrices like river water or wastewater.¹ For instance, a natural water sample might contain high concentrations of organic colloids or soot that would interfere with DLS measurements of silver nanoparticles. Because spICP-MS is element-specific, it can ignore these background "natural" particles and focus solely on the target metal, such as silver or gold.^1,2

How is spICP-MS being used to track the "fate and behavior" of pollutants?

Understanding the environmental cycle is crucial for assessing toxicity. As a result, researchers have conducted studies on silver nanoparticles used in consumer products. These studies have unveiled that spICP-MS can track how these particles are released during wash cycles and how they subsequently behave in surface water.¹ These studies have demonstrated that although some particles dissolve into silver ions over time, a significant percentage can persist for days, potentially traveling long distances through waterways.¹

What are some of the newer, "high-stakes" applications of this technology?

The scope of spICP-MS has expanded into several specialized areas:

1. Nuclear Safeguards: Recent advances in single-particle ICP-time-of-flight MS (spICP-TOF-MS) allow for the rapid isotopic analysis of uranium particles collected on environmental swipes.³ This technique can distinguish between natural, depleted, and enriched uranium in minutes, helping the International Atomic Energy Agency (IAEA) verify that nuclear facilities are not being used for undeclared activities.³
2. Resource Recovery: Researchers are using spICP-MS to quantify the efficiency of platinum-binding enzymes attached to magnetic microparticles. This supports the engineering of novel ways to recover critical materials from complex waste streams.⁴
3. Microplastics: New trimodal approaches are integrating spICP-MS with Raman spectroscopy and optical trapping to track pollutants at the microscale, providing a more comprehensive picture of plastic contamination.⁵

What are the primary technical challenges for the future?

Achieving accurate results requires extreme precision in dwell time (the time the detector spends at a mass) and settling time (the "dead time" between measurements).¹ Ideally, the settling time should be eliminated to ensure no particles are missed.¹ Furthermore, while quadrupole-based systems are excellent for single elements, time-of-flight (TOF) analyzers are becoming the gold standard for environmental "fingerprinting" because they can measure the full elemental mass spectrum of every single particle.² This allows scientists to differentiate between engineered particles and natural ones based on their multi-element signatures.

References

1. Thomas, R.; Stephan, C. Single-Particle ICP-MS: A Key Analytical Technique for Characterizing Nanoparticles. Spectroscopy 2017, 32 (3). Available at: https://www.spectroscopyonline.com/view/single-particle-icp-ms-key-analytical-technique-characterizing-nanoparticles
2. Olesik, J. W. Single Particle ICP-MS: From Engineered Nanoparticles to Natural Nanoparticles. Spectroscopy 2020, 35 (7). Available at: https://www.spectroscopyonline.com/view/single-particle-icp-ms-engineered-nanoparticles-natural-nanoparticles
3. Chasse, J. High-Throughput Isotopic Analysis of Uranium Particles for Nuclear Safeguards Using Single-Particle ICP-TOF-MS. Spectroscopy Online, 2025. https://www.spectroscopyonline.com/view/high-throughput-isotopic-analysis-of-uranium-particles-for-nuclear-safeguards-using-single-particle-icp-tof-ms (accessed July 29, 2026).
4. Chasse, J. Quantifying Platinum Binding on Protein-Functionalized Magnetic Microparticles with Single Particle-ICP-TOF-MS: A SciX Interview with Strock Award Recipient Benjamin T. Manard. Spectrosc. Suppl. 2024, 39 (s9), 32–34. Available at: https://www.spectroscopyonline.com/view/quantifying-platinum-binding-on-protein-functionalized-magnetic-microparticles-with-single-particle-icp-tof-ms-a-scix-interview-with-strock-award-recipient-benjamin-t-manard (accessed July 29, 2026).
5. Clases, D.; Wetzel, W. How Trimodal OF2i–Raman–ICP-TOFMS Is Changing Microplastic Analysis. Spectroscopy Online, 2026. https://www.spectroscopyonline.com/view/how-trimodal-of2i-raman-icp-tofms-is-changing-microplastic-analysis (accessed July 29, 2026).