From pitfalls to progress in quantitative single-cell elemental analysis by time-of-flight ICP-mass spectrometry

Dejonghe, Rinus ; Lores-Padin, Ana ; Bolea-Fernandez, Eduardo (Universidad de Zaragoza) ; Van Acker, Thibaut ; De Wever, Olivier ; Vanhaecke, Frank

Resumen: The aim of this study was to evaluate the capabilities and limitations of single-cell elemental analysis of tandem and time-of-flight ICP-mass spectrometry (SC-ICP-MS/MS and SC-ICP-ToF-MS). As partial detection of elemental distributions remains underexplored in the context of single-cell analysis, event detection, data completeness, and the reliability of derived quantitative results were investigated. The effects of detection thresholds, instrumentation type, and transient signal characteristics on the integrity of single-cell datasets and their interpretation were addressed. Red blood cells (RBCs) and peripheral blood mononuclear cells (PBMCs) were isolated, fixed with glutaraldehyde, and analyzed using both ICP-MS/MS and ICP-ToF-MS, while average contents (fg per cell) were additionally determined by bulk analysis. One key finding was that although ICP-MS/MS offers higher sensitivity, it is incompatible with multi-elemental profiling, while the sequential data acquisition for different target elements leads to inconsistent cell counts (observed cell events) during consecutive runs. In contrast, ICP-ToF-MS provides (quasi-)simultaneous detection, allowing comprehensive and consistent characterization when using an endogenous (e.g., Fe in RBCs) or exogenous (e.g., Ir from a DNA intercalator in PBMCs) cell marker. The use of such a cell marker reveals how many cells remain undetected for each element under real experimental conditions. Second, by varying signal thresholds during data processing, the influence on (partially) detected mass distributions and the impact on mean signal intensities were evaluated. This confirmed that when detection thresholds exclude low-intensity events, the resulting distributions are biased. This study underscores the need for improved instrumental sensitivity for biologically relevant low-mass elements, especially for ToF-based ICP-mass spectrometers, as well as for careful interpretation of (partially) detected datasets to avoid misleading conclusions.

Idioma: Inglés

DOI: 10.1016/j.sab.2025.107384

Año: 2026

Publicado en: Spectrochimica Acta - Part B Atomic Spectroscopy 236 (2026), 107384 [15 pp.]
ISSN: 0584-8547

Financiación: info:eu-repo/grantAgreement/ES/MICINN/RYC2021-031093-I

Tipo y forma: Article (Published version)

Área (Departamento): Área Química Analítica (Dpto. Química Analítica)