Call: +34 976 761 175
Email: maiteam@unizar.es
Address: c/Pedro Cerbuna 12, Universidad de Zaragoza, Facultad de Ciencias, Departamento de Química Analítica – Zaragoza (Spain)
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PUBLICATIONS
2025
Bazo, Antonio; Bolea-Fernandez, Eduardo; Rua-Ibarz, Ana; Aramendía, Maite; Resano, Martín
En: Anal. Chem., 2025, ISSN: 1520-6882.
@article{nokey,
title = {Ions with Ions, Entities with Entities: A Proof-of-Concept Study Using the SELM-1 Yeast Certified Reference Material for Intra- and Extracellular Se Quantification via Single-Cell ICP-Mass Spectrometry},
author = {Antonio Bazo and Eduardo Bolea-Fernandez and Ana Rua-Ibarz and Maite Aramendía and Martín Resano},
url = {https://pubs.acs.org/doi/10.1021/acs.analchem.5c01588},
doi = {https://doi.org/10.1021/acs.analchem.5c01588},
issn = {1520-6882},
year = {2025},
date = {2025-06-07},
urldate = {2025-06-07},
journal = {Anal. Chem.},
abstract = {In this work, two novel nanoparticle (NP)-based calibration strategies, external calibration and a relative method, have been explored for single-cell ICP-mass spectrometry (SC-ICP-MS) analysis. The fundamental principle of these methods is to rely on individual entities (well-characterized NPs of the target analyte) for calibration rather than on ionic standard solutions. The performance of the NP-based calibration approaches has been compared to that of the reference method (particle size with AuNP standards). In addition to the intracellular Se content (mass per individual cell), the extracellular Se (dissolved fraction) was also determined directly and simultaneously using the average background from the SC-ICP-MS time-resolved signal. The figures-of-merit of the methods developed have been evaluated by relying on the analysis of the SELM-1 cell-certified reference material, consisting of Se-enriched yeast cells, and certified for its total Se content (intracellular + extracellular Se). All methods successfully determined the Se elemental contents, but an improvement in accuracy and precision was observed for the NP-based methods compared to the reference one. Furthermore, the NP-based methods were found to be less time-consuming, more straightforward, and more user-friendly in terms of calculations. These results open new avenues for calibration in quantitative SC-ICP-MS analysis and call for a fundamental change in the methodology, where the determination of ionic contents is based on the use of ionic standard solutions for calibration, while the determination of elemental contents in discrete micro/nanoentities, such as cells, should ideally be based on calibration using standard entities, thus avoiding the need to calculate a transport efficiency coefficient.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In this work, two novel nanoparticle (NP)-based calibration strategies, external calibration and a relative method, have been explored for single-cell ICP-mass spectrometry (SC-ICP-MS) analysis. The fundamental principle of these methods is to rely on individual entities (well-characterized NPs of the target analyte) for calibration rather than on ionic standard solutions. The performance of the NP-based calibration approaches has been compared to that of the reference method (particle size with AuNP standards). In addition to the intracellular Se content (mass per individual cell), the extracellular Se (dissolved fraction) was also determined directly and simultaneously using the average background from the SC-ICP-MS time-resolved signal. The figures-of-merit of the methods developed have been evaluated by relying on the analysis of the SELM-1 cell-certified reference material, consisting of Se-enriched yeast cells, and certified for its total Se content (intracellular + extracellular Se). All methods successfully determined the Se elemental contents, but an improvement in accuracy and precision was observed for the NP-based methods compared to the reference one. Furthermore, the NP-based methods were found to be less time-consuming, more straightforward, and more user-friendly in terms of calculations. These results open new avenues for calibration in quantitative SC-ICP-MS analysis and call for a fundamental change in the methodology, where the determination of ionic contents is based on the use of ionic standard solutions for calibration, while the determination of elemental contents in discrete micro/nanoentities, such as cells, should ideally be based on calibration using standard entities, thus avoiding the need to calculate a transport efficiency coefficient.
Bazo, Antonio; Bolea-Fernandez, Eduardo; Billimoria, Kharmen; Rua-Ibarz, Ana; Aramendía, Maite; Menero-Valdés, Paula; Morley, Jack; Neves, Sara; Sánchez-Cachero, Armando; Goenaga-Infante, Heidi; Resano, Martín
En: J. Anal. At. Spectrom., pp. -, 2025.
@article{D5JA00253B,
title = {A novel particle mass calibration strategy for the quantification of AuNPs in single cancer cells via laser ablation ICP-mass spectrometry. A case study},
author = {Antonio Bazo and Eduardo Bolea-Fernandez and Kharmen Billimoria and Ana Rua-Ibarz and Maite Aramendía and Paula Menero-Valdés and Jack Morley and Sara Neves and Armando Sánchez-Cachero and Heidi Goenaga-Infante and Martín Resano},
url = {http://dx.doi.org/10.1039/D5JA00253B},
doi = {10.1039/D5JA00253B},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
journal = {J. Anal. At. Spectrom.},
pages = {-},
publisher = {The Royal Society of Chemistry},
abstract = {Laser ablation ICP-mass spectrometry (LA-ICP-MS) has developed as a powerful tool for elemental quantitative analysis of individual cells, assuring that the content of each cell is analyzed individually. However, this technique is still limited by the difficulties associated with calibration using solid standards. This work proposes a particle mass calibration strategy that is independent of both the properties and thickness of the gelatin films used for calibration, overcoming a significant drawback of previously established methods. The fundamental principle of this strategy relies on the individual ablation of nanoparticles (NPs) of well-characterized size that are embedded in the films, so that their mass can be directly used for calibration without the need to calculate their exact concentration within the gelatin. The performance of the newly developed method was compared to that of the previously reported approaches (ionic and particle number calibration) in terms of linearity and homogeneity between different films prepared from the same gelatin solution. As a case study, the three calibration strategies were used for the quantitative analysis of HeLa cancer cells exposed to AuNPs. In parallel, in-suspension single-cell (SC) ICP-MS Au data were obtained and used as reference for comparison with the three LA-SC-ICP-MS strategies. The results obtained with the novel particle mass approach demonstrated better accuracy and repeatability over three different working sessions, addressing key limitations and providing a robust and reliable method for quantitative LA-SC-ICP-MS analysis. The particle mass method holds promise for quantitative LA-ICP-MS analysis of samples beyond NP-exposed cells, such as biological tissues.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Laser ablation ICP-mass spectrometry (LA-ICP-MS) has developed as a powerful tool for elemental quantitative analysis of individual cells, assuring that the content of each cell is analyzed individually. However, this technique is still limited by the difficulties associated with calibration using solid standards. This work proposes a particle mass calibration strategy that is independent of both the properties and thickness of the gelatin films used for calibration, overcoming a significant drawback of previously established methods. The fundamental principle of this strategy relies on the individual ablation of nanoparticles (NPs) of well-characterized size that are embedded in the films, so that their mass can be directly used for calibration without the need to calculate their exact concentration within the gelatin. The performance of the newly developed method was compared to that of the previously reported approaches (ionic and particle number calibration) in terms of linearity and homogeneity between different films prepared from the same gelatin solution. As a case study, the three calibration strategies were used for the quantitative analysis of HeLa cancer cells exposed to AuNPs. In parallel, in-suspension single-cell (SC) ICP-MS Au data were obtained and used as reference for comparison with the three LA-SC-ICP-MS strategies. The results obtained with the novel particle mass approach demonstrated better accuracy and repeatability over three different working sessions, addressing key limitations and providing a robust and reliable method for quantitative LA-SC-ICP-MS analysis. The particle mass method holds promise for quantitative LA-ICP-MS analysis of samples beyond NP-exposed cells, such as biological tissues.
Bazo, Antonio; López-Villellas, Lorién; Mataloni, Matilde; Bolea-Fernandez, Eduardo; Rua-Ibarz, Ana; Grotti, Marco; Aramendía, Maite; Resano, Martín
Improving detection and figures of merit in single-particle inductively coupled plasma-mass spectrometry via transient event heights Journal Article
En: Analytica Chimica Acta, vol. 1378, pp. 344694, 2025, ISSN: 0003-2670.
@article{BAZO2025344694,
title = {Improving detection and figures of merit in single-particle inductively coupled plasma-mass spectrometry via transient event heights},
author = {Antonio Bazo and Lorién López-Villellas and Matilde Mataloni and Eduardo Bolea-Fernandez and Ana Rua-Ibarz and Marco Grotti and Maite Aramendía and Martín Resano},
url = {https://www.sciencedirect.com/science/article/pii/S0003267025010888},
doi = {https://doi.org/10.1016/j.aca.2025.344694},
issn = {0003-2670},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
journal = {Analytica Chimica Acta},
volume = {1378},
pages = {344694},
abstract = {Background
Single-particle inductively coupled plasma-mass spectrometry (SP-ICP-MS) is a powerful method for characterizing micro- and nanoparticulate materials. The technique primarily relies on the linear relationship between the integrated intensities of individual events (peak areas) and the analyte mass, though transit times (peak widths) have also been used for quantitative purposes. This work (1) evaluates the potential of using peak heights as analytical signals in SP-ICP-MS, (2) introduces a new method for determining peak heights, and (3) explores scenarios in which peak height offers added value over the commonly used SP-ICP-MS signals.
Results
A new method was proposed to estimate peak height values in SP-ICP-MS accurately. The cumulative intensity across consecutive dwell times was modeled using a third-degree polynomial, from which the adjusted peak height was derived. This approach reduces the uncertainty associated with using raw maximum intensity values, yielding NP distributions comparable to those obtained via integrated intensities. The effect of dwell time on peak height was also evaluated. An optimal range (50 μs–200 μs) was identified, where a linear relationship was observed between the peak height and the square of the NP diameter. Within this range, peak height showed the lowest bias when characterizing smaller NPs, indicating the potential to improve the limit of quantification (LoQ). Additionally, peak heights proved helpful in determining the limit of detection (LoD) and setting appropriate threshold values for data processing, thereby helping to flag incorrect resultsand addressing a challenge in SP-ICP-MS analysis.
Significance
This is the first study to evaluate peak height as an analytical signal in SP-ICP-MS. The results highlight its advantages in specific applications, such as sizing NPs near the LoD, and in supporting the more reliable use of other signals, such as peak areas, by helping to identify incorrect threshold selection that could lead to biased distributions. Finally, monitoring peak heights allows for a more realistic and assumption-free determination of the LoD.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Background
Single-particle inductively coupled plasma-mass spectrometry (SP-ICP-MS) is a powerful method for characterizing micro- and nanoparticulate materials. The technique primarily relies on the linear relationship between the integrated intensities of individual events (peak areas) and the analyte mass, though transit times (peak widths) have also been used for quantitative purposes. This work (1) evaluates the potential of using peak heights as analytical signals in SP-ICP-MS, (2) introduces a new method for determining peak heights, and (3) explores scenarios in which peak height offers added value over the commonly used SP-ICP-MS signals.
Results
A new method was proposed to estimate peak height values in SP-ICP-MS accurately. The cumulative intensity across consecutive dwell times was modeled using a third-degree polynomial, from which the adjusted peak height was derived. This approach reduces the uncertainty associated with using raw maximum intensity values, yielding NP distributions comparable to those obtained via integrated intensities. The effect of dwell time on peak height was also evaluated. An optimal range (50 μs–200 μs) was identified, where a linear relationship was observed between the peak height and the square of the NP diameter. Within this range, peak height showed the lowest bias when characterizing smaller NPs, indicating the potential to improve the limit of quantification (LoQ). Additionally, peak heights proved helpful in determining the limit of detection (LoD) and setting appropriate threshold values for data processing, thereby helping to flag incorrect resultsand addressing a challenge in SP-ICP-MS analysis.
Significance
This is the first study to evaluate peak height as an analytical signal in SP-ICP-MS. The results highlight its advantages in specific applications, such as sizing NPs near the LoD, and in supporting the more reliable use of other signals, such as peak areas, by helping to identify incorrect threshold selection that could lead to biased distributions. Finally, monitoring peak heights allows for a more realistic and assumption-free determination of the LoD.
Single-particle inductively coupled plasma-mass spectrometry (SP-ICP-MS) is a powerful method for characterizing micro- and nanoparticulate materials. The technique primarily relies on the linear relationship between the integrated intensities of individual events (peak areas) and the analyte mass, though transit times (peak widths) have also been used for quantitative purposes. This work (1) evaluates the potential of using peak heights as analytical signals in SP-ICP-MS, (2) introduces a new method for determining peak heights, and (3) explores scenarios in which peak height offers added value over the commonly used SP-ICP-MS signals.
Results
A new method was proposed to estimate peak height values in SP-ICP-MS accurately. The cumulative intensity across consecutive dwell times was modeled using a third-degree polynomial, from which the adjusted peak height was derived. This approach reduces the uncertainty associated with using raw maximum intensity values, yielding NP distributions comparable to those obtained via integrated intensities. The effect of dwell time on peak height was also evaluated. An optimal range (50 μs–200 μs) was identified, where a linear relationship was observed between the peak height and the square of the NP diameter. Within this range, peak height showed the lowest bias when characterizing smaller NPs, indicating the potential to improve the limit of quantification (LoQ). Additionally, peak heights proved helpful in determining the limit of detection (LoD) and setting appropriate threshold values for data processing, thereby helping to flag incorrect resultsand addressing a challenge in SP-ICP-MS analysis.
Significance
This is the first study to evaluate peak height as an analytical signal in SP-ICP-MS. The results highlight its advantages in specific applications, such as sizing NPs near the LoD, and in supporting the more reliable use of other signals, such as peak areas, by helping to identify incorrect threshold selection that could lead to biased distributions. Finally, monitoring peak heights allows for a more realistic and assumption-free determination of the LoD.
2024
Aramendía, Maite; Souza, André L. M.; Nakadi, Flávio V.; Resano, Martín
En: J. Anal. At. Spectrom., vol. 39, pp. 767-779, 2024.
@article{D3JA00420A,
title = {Boron elemental and isotopic determination via the BF diatomic molecule using high-resolution continuum source graphite furnace molecular absorption spectrometry},
author = {Maite Aramendía and André L. M. Souza and Flávio V. Nakadi and Martín Resano},
url = {http://dx.doi.org/10.1039/D3JA00420A},
doi = {10.1039/D3JA00420A},
year = {2024},
date = {2024-01-01},
urldate = {2024-01-01},
journal = {J. Anal. At. Spectrom.},
volume = {39},
pages = {767-779},
publisher = {The Royal Society of Chemistry},
abstract = {Boron trace determination in biological materials is needed in different fields of application. Direct B determination by means of Graphite Furnace Atomic Absorption Spectrometry (SS-GFAAS) has been used in the past for this purpose, offering good detection limits hardly achievable by other techniques. However, such methods require the use of high atomization temperatures combined with large integration times to promote B atomization, which dramatically reduces the lifetime of the instrument's graphite parts. In this work, a new perspective for B determination by means of Graphite Furnace Molecular Absorption Spectrometry (GFMAS) is proposed. B was detected as the diatomic molecule BF (boron monofluoride), deploying a gas phase reaction with CH3F as fluorinating agent. Based on this strategy, a method for the direct determination of B in two biological certified reference materials (NIST SRM 1570a spinach leaves and NIST SRM 1573a tomato leaves) has been developed, providing similar detection capabilities to the GFAAS method (LOD of 0.24 ng) but requiring much milder furnace conditions. Moreover, the appearance of memory effects, very common in GFAAS methods, is also avoided with this method. Straightforward calibration with aqueous standard solutions was also found to be possible. To this end, a mixture of W (permanent), citric acid, and Ca as chemical modifiers was found to be essential for obtaining a reproducible and sufficiently sensitive signal for boron solutions, comparable to the signals obtained for the solid samples. With this method, accurate results were obtained for the direct analysis of both certified reference materials, provided that spectral interferences from the PO molecule were properly corrected. Precision values in the range of 15% RSD, as typically reported for direct solid sampling GFAAS, were found. Finally, and as an additional advantage of the GFMAS method, a large isotopic shift in the absorbance of the 10BF and 11BF molecules can be accurately monitored at a secondary transition for the BF molecule. This offers novel analytical possibilities for the method, which are also explored in this study. In this regard, control of the B concentration was found to be critical for obtaining accurate and precise isotope ratios for this element.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Boron trace determination in biological materials is needed in different fields of application. Direct B determination by means of Graphite Furnace Atomic Absorption Spectrometry (SS-GFAAS) has been used in the past for this purpose, offering good detection limits hardly achievable by other techniques. However, such methods require the use of high atomization temperatures combined with large integration times to promote B atomization, which dramatically reduces the lifetime of the instrument's graphite parts. In this work, a new perspective for B determination by means of Graphite Furnace Molecular Absorption Spectrometry (GFMAS) is proposed. B was detected as the diatomic molecule BF (boron monofluoride), deploying a gas phase reaction with CH3F as fluorinating agent. Based on this strategy, a method for the direct determination of B in two biological certified reference materials (NIST SRM 1570a spinach leaves and NIST SRM 1573a tomato leaves) has been developed, providing similar detection capabilities to the GFAAS method (LOD of 0.24 ng) but requiring much milder furnace conditions. Moreover, the appearance of memory effects, very common in GFAAS methods, is also avoided with this method. Straightforward calibration with aqueous standard solutions was also found to be possible. To this end, a mixture of W (permanent), citric acid, and Ca as chemical modifiers was found to be essential for obtaining a reproducible and sufficiently sensitive signal for boron solutions, comparable to the signals obtained for the solid samples. With this method, accurate results were obtained for the direct analysis of both certified reference materials, provided that spectral interferences from the PO molecule were properly corrected. Precision values in the range of 15% RSD, as typically reported for direct solid sampling GFAAS, were found. Finally, and as an additional advantage of the GFMAS method, a large isotopic shift in the absorbance of the 10BF and 11BF molecules can be accurately monitored at a secondary transition for the BF molecule. This offers novel analytical possibilities for the method, which are also explored in this study. In this regard, control of the B concentration was found to be critical for obtaining accurate and precise isotope ratios for this element.
Freire, Bruna Moreira; Rua-Ibarz, Ana; Nakadi, Flávio Venâncio; Bolea-Fernandez, Eduardo; Barriuso-Vargas, Juan J.; Lange, Camila Neves; Aramendía, Maite; Batista, Bruno Lemos; Resano, Martín
Tracing isotopically labeled selenium nanoparticles in plants via single-particle ICP-mass spectrometry Journal Article
En: Talanta, vol. 277, pp. 126417, 2024, ISSN: 0039-9140.
@article{FREIRE2024126417,
title = {Tracing isotopically labeled selenium nanoparticles in plants via single-particle ICP-mass spectrometry},
author = {Bruna Moreira Freire and Ana Rua-Ibarz and Flávio Venâncio Nakadi and Eduardo Bolea-Fernandez and Juan J. Barriuso-Vargas and Camila Neves Lange and Maite Aramendía and Bruno Lemos Batista and Martín Resano},
url = {https://www.sciencedirect.com/science/article/pii/S0039914024007963},
doi = {https://doi.org/10.1016/j.talanta.2024.126417},
issn = {0039-9140},
year = {2024},
date = {2024-01-01},
journal = {Talanta},
volume = {277},
pages = {126417},
abstract = {Abstract
Agronomic biofortification using selenium nanoparticles (SeNPs) shows potential for addressing selenium deficiency but further research on SeNPs-plants interaction is required before it can be effectively used to improve nutritional quality. In this work, single-particle inductively coupled plasma-mass spectrometry (SP-ICP-MS) was used for tracing isotopically labeled SeNPs (82SeNPs) in Oryza sativa L. tissues. For this purpose, SeNPs with natural isotopic abundance and 82SeNPs were synthesized by a chemical method. The NPs characterization by transmission electron microscopy (TEM) confirmed that enriched NPs maintained the basic properties of unlabeled NPs, showing spherical shape, monodispersity, and sizes in the nano-range (82.8 ± 6.6 nm and 73.2 ± 4.4 nm for SeNPs and 82SeNPs, respectively). The use of 82SeNPs resulted in an 11-fold enhancement in the detection power for ICP-MS analysis, accompanied by an improvement in the signal-to-background ratio and a reduction of the size limits of detection from 89.9 to 39.9 nm in SP-ICP-MS analysis. This enabled 82SeNPs to be tracked in O. sativa L. plants cultivated under foliar application of 82SeNPs. Tracing studies combining SP-ICP-MS and TEM-energy-dispersive X-ray spectroscopy data confirmed the uptake of intact 82SeNPs by rice leaves, with most NPs remaining in the leaves and very few particles translocated to shoots and roots. Translocation of Se from leaves to roots and shoots was found to be lower when applied as NPs compared to selenite application. From the size distributions, as obtained by SP-ICP-MS, it can be concluded that a fraction of the 82SeNPs remained within the same size range as that of the applied NP suspension, while other fraction underwent an agglomeration process in the leaves, as confirmed by TEM images. This illustrates the potential of SP-ICP-MS analysis of isotopically enriched 82SeNPs for tracing NPs in the presence of background elements within complex plant matrices, providing important information about the uptake, accumulation, and biotransformation of SeNPs in rice plants.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Abstract
Agronomic biofortification using selenium nanoparticles (SeNPs) shows potential for addressing selenium deficiency but further research on SeNPs-plants interaction is required before it can be effectively used to improve nutritional quality. In this work, single-particle inductively coupled plasma-mass spectrometry (SP-ICP-MS) was used for tracing isotopically labeled SeNPs (82SeNPs) in Oryza sativa L. tissues. For this purpose, SeNPs with natural isotopic abundance and 82SeNPs were synthesized by a chemical method. The NPs characterization by transmission electron microscopy (TEM) confirmed that enriched NPs maintained the basic properties of unlabeled NPs, showing spherical shape, monodispersity, and sizes in the nano-range (82.8 ± 6.6 nm and 73.2 ± 4.4 nm for SeNPs and 82SeNPs, respectively). The use of 82SeNPs resulted in an 11-fold enhancement in the detection power for ICP-MS analysis, accompanied by an improvement in the signal-to-background ratio and a reduction of the size limits of detection from 89.9 to 39.9 nm in SP-ICP-MS analysis. This enabled 82SeNPs to be tracked in O. sativa L. plants cultivated under foliar application of 82SeNPs. Tracing studies combining SP-ICP-MS and TEM-energy-dispersive X-ray spectroscopy data confirmed the uptake of intact 82SeNPs by rice leaves, with most NPs remaining in the leaves and very few particles translocated to shoots and roots. Translocation of Se from leaves to roots and shoots was found to be lower when applied as NPs compared to selenite application. From the size distributions, as obtained by SP-ICP-MS, it can be concluded that a fraction of the 82SeNPs remained within the same size range as that of the applied NP suspension, while other fraction underwent an agglomeration process in the leaves, as confirmed by TEM images. This illustrates the potential of SP-ICP-MS analysis of isotopically enriched 82SeNPs for tracing NPs in the presence of background elements within complex plant matrices, providing important information about the uptake, accumulation, and biotransformation of SeNPs in rice plants.
Agronomic biofortification using selenium nanoparticles (SeNPs) shows potential for addressing selenium deficiency but further research on SeNPs-plants interaction is required before it can be effectively used to improve nutritional quality. In this work, single-particle inductively coupled plasma-mass spectrometry (SP-ICP-MS) was used for tracing isotopically labeled SeNPs (82SeNPs) in Oryza sativa L. tissues. For this purpose, SeNPs with natural isotopic abundance and 82SeNPs were synthesized by a chemical method. The NPs characterization by transmission electron microscopy (TEM) confirmed that enriched NPs maintained the basic properties of unlabeled NPs, showing spherical shape, monodispersity, and sizes in the nano-range (82.8 ± 6.6 nm and 73.2 ± 4.4 nm for SeNPs and 82SeNPs, respectively). The use of 82SeNPs resulted in an 11-fold enhancement in the detection power for ICP-MS analysis, accompanied by an improvement in the signal-to-background ratio and a reduction of the size limits of detection from 89.9 to 39.9 nm in SP-ICP-MS analysis. This enabled 82SeNPs to be tracked in O. sativa L. plants cultivated under foliar application of 82SeNPs. Tracing studies combining SP-ICP-MS and TEM-energy-dispersive X-ray spectroscopy data confirmed the uptake of intact 82SeNPs by rice leaves, with most NPs remaining in the leaves and very few particles translocated to shoots and roots. Translocation of Se from leaves to roots and shoots was found to be lower when applied as NPs compared to selenite application. From the size distributions, as obtained by SP-ICP-MS, it can be concluded that a fraction of the 82SeNPs remained within the same size range as that of the applied NP suspension, while other fraction underwent an agglomeration process in the leaves, as confirmed by TEM images. This illustrates the potential of SP-ICP-MS analysis of isotopically enriched 82SeNPs for tracing NPs in the presence of background elements within complex plant matrices, providing important information about the uptake, accumulation, and biotransformation of SeNPs in rice plants.