Analysis of TiO2 Nanoparticles in Foods and Personal Care Products by Single Particle ICP-QQQ

Importance of the Topic

The widespread use of titanium dioxide (TiO2) as a whitening and brightening agent in foods and personal care products has raised concerns over the presence of nanoscale particles and their potential health impacts. Reliable characterization of TiO2 nanoparticles (NPs) is essential for compliance with evolving regulatory definitions of nanomaterials and for assessing consumer exposure and safety.

Objectives and Study Overview

This study demonstrates a robust single-particle ICP-QQQ method to detect and size TiO2 NPs in complex matrices such as foods (milk, salad dressing, cake decoration) and toothpaste. The key aim is to overcome analytical challenges posed by isobaric and polyatomic interferences, particularly the overlap of 48Ti+ with 48Ca+ and other matrix components.

Methodology and Instrumentation

A tailored sample preparation protocol was developed for each product type, involving dilution, dispersion with surfactants, and sonication. The analytical platform comprised an Agilent 8900 triple quadrupole ICP-MS operated in MS/MS mass‐shift mode with mixed oxygen/hydrogen cell gas. This configuration uses the first quadrupole as a mass filter (m/z 48) and converts 48Ti+ into 48Ti16O+ (m/z 64) in the reaction cell, effectively eliminating interferences from 48Ca and common polyatomics.

Main Results and Discussion

• The O2/H2 MS/MS mode reduced apparent Ti background from calcium, sulfur, and phosphorus by over three orders of magnitude compared to no‐gas operation, enabling detection down to 30 nm particle diameter.
• Spiked tests in diluted milk produced accurate mass recoveries (71–85 %) and consistent size distributions for both 115 nm (anatase) and <50 nm (mixed anatase/rutile) reference TiO2 NPs.
• Analysis of consumer samples revealed variable TiO2 NP profiles: toothpaste median size ~155 nm (22 % <100 nm), salad dressing ~334 nm (3 % <100 nm), cake decoration ~54 nm (70 % <100 nm).

Benefits and Practical Applications

This method offers rapid, multi‐element capability with high sensitivity, supporting regulatory compliance (e.g., EU nanomaterial labeling) and safety evaluations. It complements electron microscopy by providing particle number concentration and dissolved fraction in a single analysis, making it suitable for quality control in food, cosmetics, and environmental monitoring.

Future Trends and Applications

Advances in triple quadrupole ICP‐MS will enable lower size detection limits and higher throughput. Integration with automated sample handling and data processing software will facilitate routine screening of nanomaterials. Emerging regulations may mandate standardized spICP‐MS protocols across laboratories to ensure global harmonization.

Conclusion

An MS/MS mass‐shift spICP‐QQQ approach effectively resolves key interferences on 48Ti, achieving sub‐50 nm detection in complex matrices. The method delivers reliable size distributions and quantification of TiO2 NPs in foods and personal care products, addressing critical analytical needs for regulatory and safety assessments.

References

• Regulation (EC) No 1333/2008 on food additives. Official Journal of the European Union L354:16–33.
• Commission Recommendation 2011/696/EU on the definition of nanomaterial. Official Journal L275:38–40.
• EFSA Scientific Opinion on titanium dioxide (E 171) as a food additive. EFSA Journal 14(9):4545 (2016).
• Correia M, Uusimäki T, Philippe A, Loeschner K. Separations 2018;5(4):56.
• Yamanaka M, Wilbur S. Agilent Application Note 5991-8358EN (2019).
• NIST SRM 1898: Titanium Dioxide Nanoparticles.
• ANSES assessment and French ban of E171 in foods (effective 2020).
• European Commission Recommendation for nanomaterial size distribution and concentration (2011).