List of key publications on the characterization of nanoparticles by FFF-MALS coupled to ICP-MS

Importance of the Topic

Asymmetric flow field-flow fractionation (AF4) coupled with multi-angle light scattering (MALS) and inductively coupled plasma mass spectrometry (ICP-MS) provides a unique combination of size-resolved separation and element-specific detection. This hyphenated technique is vital for understanding the behavior, fate, and concentration of nanoparticles in environmental systems, industrial processes, and consumer products, addressing critical needs in nanomaterial quality control, regulatory compliance, and risk assessment.

Objectives and Study Overview

This compilation reviews key publications demonstrating AF4-MALS-ICP-MS applications for characterizing metallic and inorganic nanoparticles in diverse matrices. Studies include methodological developments, validation against reference materials, exploration of matrix effects, and real-world applications in environmental, soil, and consumer product analyses.

Methodology and Instrumentation

Most studies employ a Wyatt Eclipse AF4 system for hydrodynamic separation, followed by:

• MALS detection for determination of hydrodynamic diameter and size distribution.
• ICP-MS detection (single-particle, sector field, or conventional) for element-specific quantification.
• Capillary electrophoresis hyphenation in selected cases for speciation analysis.

Common instrument pairings include:

• Wyatt Eclipse AF4 + PerkinElmer ICP-MS
• Wyatt Eclipse AF4 + Thermo Scientific ICP-MS
• Wyatt Eclipse AF4 + Agilent ICP-MS

Main Results and Discussion

Key findings across the literature:

• Accurate sizing and quantification of Ag and Au nanoparticles in environmental waters and consumer goods, with single-particle sensitivity (Aznar et al., Loeschner et al.).
• Validation of AF4-ICP-MS protocols using silica nanoparticle standards, demonstrating reproducibility and low size bias (Barahona et al.).
• Critical impact of sample handling and matrix composition on nanoparticle recovery and fractionation profiles in soils and natural waters (Claveranne-Lamolère et al., Loosli et al.).
• Isotopic labeling strategies enabling discrimination of nanoparticle populations in complex media (Gigault et al.).
• Application extension to non-metallic species: antimony redox speciation in complex samples and phosphorus-bound colloid release under anoxia (Hansen et al., Henderson et al.).

Benefits and Practical Applications

AF4-MALS-ICP-MS offers:

• Comprehensive size and elemental profiling for engineered and natural nanoparticles.
• Enhanced understanding of nanoparticle transport, aggregation, and dissolution in environmental and biological systems.
• Robust quality control for nanomaterial production and consumer product safety assessment.
• Framework for developing reference materials and standardized analytical protocols.

Future Trends and Potential Applications

Emerging directions include integration with advanced detectors (e.g., single-particle ICP-MS), coupling with high-resolution speciation techniques (capillary electrophoresis), and incorporation of real-time imaging (TEM). Advances in automation, miniaturization, and data analytics, including machine learning for chromatogram deconvolution, will further expand capabilities in complex sample analysis and environmental monitoring.

Conclusion

AF4-MALS-ICP-MS has matured into a versatile and reliable platform for nanoparticle characterization across environmental, industrial, and consumer contexts. Ongoing methodological refinements and interdisciplinary collaborations will drive its broader adoption in nanoscience, regulatory arenas, and risk assessment.

Reference

• Aznar R., et al. Quantification and size characterization of silver nanoparticles in environmental aqueous samples and consumer products by single particle ICP-MS. Talanta. 175(1):200-208 (2017).
• Hagendorfer H., et al. Application of an asymmetric flow field flow fractionation multi-detector approach for metallic engineered nanoparticle characterization – Prospects and limitations demonstrated on Au nanoparticles. Analytica Chimica Acta. 706(2):367-378 (2011).
• Barahona F., et al. Simultaneous determination of size and quantification of silica nanoparticles by asymmetric flow field-flow fractionation coupled to ICPMS using silica nanoparticle standards. J Anal Chem. 87(5):3039-3047 (2015).
• Meermann B., et al. Fraction-related quantification of silver nanoparticles via on-line species-unspecific post-channel isotope dilution in combination with AF4/sector field ICP-MS. J Anal At Spectrom. 29:287-296 (2014).
• Helsper J.P.F.G., et al. Physicochemical characterization of titanium dioxide pigments using size determination techniques and AF4 hyphenated with ICP-MS. Anal Bioanal Chem. 408(24):6679-6691 (2016).
• Dubascoux S., et al. On-line and off-line quantification of trace elements associated to colloids by As-Fl-FFF and ICP-MS. Talanta. 77(1):60-65 (2008).
• Ulrich A., et al. Critical aspects of sample handling for direct nanoparticle analysis and analytical challenges using asymmetric field flow fractionation in a multi-detector approach. J Anal At Spectrom. 27:1120-1130 (2012).
• Loeschner K., et al. Optimization and evaluation of asymmetric flow field-flow fractionation of silver nanoparticles. J Chromatogr A. 1272:116-125 (2013).
• Gigault J., et al. Differentiation and characterization of isotopically modified silver nanoparticles in aqueous media using asymmetric flow field-flow fractionation coupled to optical detection and mass spectrometry. Analytica Chimica Acta. 763(6):57-66 (2012).
• Claveranne-Lamolère C., et al. Investigation of uranium–colloid interactions in soil by dual field-flow fractionation/capillary electrophoresis hyphenated with ICP-MS. Talanta. 85(5):2504-2510 (2011).
• Henderson R., et al. Anoxia-induced release of colloid- and nanoparticle-bound phosphorus in grassland soils. Environ Sci Technol. 46(21):11727-11734 (2012).
• Meisterjahn B., et al. Asymmetrical flow-field-flow fractionation coupled with ICP-MS for the analysis of gold nanoparticles in the presence of natural nanoparticles. J Chromatogr A. 1372:204-211 (2014).
• El Hadri H., et al. Optimization of flow field-flow fractionation for the characterization of natural colloids. Anal Bioanal Chem. 406(6):1639-1649 (2014).
• Claveranne-Lamolère C., et al. Colloidal transport of uranium in soil: size fractionation and characterization by field-flow fractionation–multi-detection. J Chromatogr A. 1216(52):9113-9119 (2009).
• Schultz C.L., et al. Influence of soil porewater properties on the fate and toxicity of silver nanoparticles to Caenorhabditis elegans. Environ Toxicol Chem. 37(10):2609-2618 (2018).
• Loosli F., et al. Dispersion of natural nanomaterials in surface waters for better characterization of their physicochemical properties by AF4-ICP-MS-TEM. Sci Total Environ. 682:663-672 (2019).
• Bocca B., et al. ICP-MS based methods to characterize nanoparticles of TiO2 and ZnO in sunscreens with focus on regulatory and safety issues. Sci Total Environ. 630:922-930 (2018).
• Grombe R., et al. Production of reference materials for the detection and size determination of silica nanoparticles in tomato soup. Anal Bioanal Chem. 406(16):3895-3907 (2014).
• Loeschner K., et al. Detection and characterization of silver nanoparticles in chicken meat by asymmetric flow field-flow fractionation with detection by conventional or single particle ICP-MS. Anal Bioanal Chem. 405(25):8185-8195 (2014).
• Schmidt B., et al. Combining AF4 with light-scattering and ICP-MS for characterization of nanoclay used in biopolymer nanocomposites. Food Addit Contam. 26(12):1619-1627 (2009).
• Hansen C., et al. Quantitative HPLC-ICP-MS analysis of antimony redox speciation in complex sample matrices: new insights into the Sb-chemistry causing poor chromatographic recoveries. Analyst. 136:996-1002 (2011).