Call: +34 876 553 510
Email: arua@unizar.es
Address: c/Pedro Cerbuna 12, Universidad de Zaragoza, Facultad de Ciencias, Departamento de Química Analítica – Zaragoza (Spain)
ABOUT ME
Ana María Rua Ibarz obtained her Bachelor and Master degrees in Chemistry from the University of Zaragoza (Zaragoza, Spain). She carried out her PhD research at Ghent University (Ghent, Belgium) focused on method development and applications of high-precision isotopic analysis of Hg using cold-vapor generation multi-collector ICP-mass spectrometry instrumentation (CVG-MC-ICP-MS), and he obtained her PhD degree in 2018. In May 2018, after a competitive selection procedure held among international researchers, Ana obtained a postdoctoral position at the Flemish Institute for Technological Research (VITO) in Mol (Belgium), for carrying out a research project intended to explore new analytical strategies for nanoparticle characterization. In March 2020, she started working as postdoctoral researcher at Ghent University on a project in collaboration with TotalEnergies (Feluy, Belgium). The project was based on method development for quantitative elemental and spatially resolved analysis of relevant samples in petrochemistry, such as catalysts, polymers and rocks via laser ablation ICP-MS (LA-ICP-MS). Since November 2022, she is working as postdoctoral researcher at the University of Zaragoza (Spain) after she was awarded a Marie Sklodowska-Curie (MSCA)-COFUND International Fellowship Programme for Talent Attraction to the Campus of International Excellence Campus Iberus. Her research project is entitled “Exploring new venues for the characterization of nanomaterials and microplastics via plasma spectroscopy”.
PUBLICATIONS
2024
Bazo, Antonio; Bolea-Fernandez, Eduardo; Rua-Ibarz, Ana; Aramendía, Maite; Resano, Martín
En: Analytica Chimica Acta, vol. 1331, pp. 343305, 2024, ISSN: 0003-2670.
@article{BAZO2024343305,
title = {Intensity- and time-based strategies for micro/nano-sizing via single-particle ICP-mass spectrometry: A comparative assessment using Au and SiO2 as model particles},
author = {Antonio Bazo and Eduardo Bolea-Fernandez and Ana Rua-Ibarz and Maite Aramendía and Martín Resano},
url = {https://www.sciencedirect.com/science/article/pii/S0003267024011061},
doi = {https://doi.org/10.1016/j.aca.2024.343305},
issn = {0003-2670},
year = {2024},
date = {2024-01-01},
urldate = {2024-01-01},
journal = {Analytica Chimica Acta},
volume = {1331},
pages = {343305},
abstract = {Background
Single-particle ICP-mass spectrometry (SP-ICP-MS) is a powerful method for micro/nano-particle (MNP) sizing. Despite the outstanding evolution of the technique in the last decade, most studies still rely on traditional approaches based on (1) the use of integrated intensity as the analytical signal and (2) the calculation of the transport efficiency (TE). However, the increasing availability of MNP standards and advancements in hardware and software have unveiled new venues for MNP sizing, including TE-independent and time-based approaches. This work systematically examines these different methodologies to identify and summarize their strengths and weaknesses, thus helping to determine their preferred application areas.
Results
Different SP-ICP-MS methods for MNP sizing were assessed using AuNPs (20–70 nm) and SiO2MNPs (100–1000 nm). Among TE-dependent approaches, the particle frequency method was characterized by larger uncertainties than the particle size method. The results of the latter were dependent on the appropriate selection of the reference MNP, making the use of multiple reference MNPs recommended. TE-independent methods were based on external (linear and polynomial) calibrations and a relative approach. These methods exhibited the lowest uncertainties of all the strategies evaluated. External calibrations benefited from simpler calculations, but their application could be hindered by a lack of reference MNPs within the desired size range or by the need for interpolations outside the calibration range. Finally, transit time signals are directly proportional to the MNP size rather than its mass. The time-based method demonstrated adequate performance for sizing AuNPs but failed when sizing the largest SiO2MNPs (1000 nm).
Significance and novelty
This work provides further insights into the application of different SP-ICP-MS methodologies for MNP sizing. Both TE-independent approaches and the monitoring of the transit time as the analytical signal are underused strategies; in this context, a Python script was developed for accurate transit time measurement. After 20 years of development, a quantitative comparison of the different methodologies, including the most novel approaches, is deemed necessary for further growth on solid theoretical ground.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Background
Single-particle ICP-mass spectrometry (SP-ICP-MS) is a powerful method for micro/nano-particle (MNP) sizing. Despite the outstanding evolution of the technique in the last decade, most studies still rely on traditional approaches based on (1) the use of integrated intensity as the analytical signal and (2) the calculation of the transport efficiency (TE). However, the increasing availability of MNP standards and advancements in hardware and software have unveiled new venues for MNP sizing, including TE-independent and time-based approaches. This work systematically examines these different methodologies to identify and summarize their strengths and weaknesses, thus helping to determine their preferred application areas.
Results
Different SP-ICP-MS methods for MNP sizing were assessed using AuNPs (20–70 nm) and SiO2MNPs (100–1000 nm). Among TE-dependent approaches, the particle frequency method was characterized by larger uncertainties than the particle size method. The results of the latter were dependent on the appropriate selection of the reference MNP, making the use of multiple reference MNPs recommended. TE-independent methods were based on external (linear and polynomial) calibrations and a relative approach. These methods exhibited the lowest uncertainties of all the strategies evaluated. External calibrations benefited from simpler calculations, but their application could be hindered by a lack of reference MNPs within the desired size range or by the need for interpolations outside the calibration range. Finally, transit time signals are directly proportional to the MNP size rather than its mass. The time-based method demonstrated adequate performance for sizing AuNPs but failed when sizing the largest SiO2MNPs (1000 nm).
Significance and novelty
This work provides further insights into the application of different SP-ICP-MS methodologies for MNP sizing. Both TE-independent approaches and the monitoring of the transit time as the analytical signal are underused strategies; in this context, a Python script was developed for accurate transit time measurement. After 20 years of development, a quantitative comparison of the different methodologies, including the most novel approaches, is deemed necessary for further growth on solid theoretical ground.
Single-particle ICP-mass spectrometry (SP-ICP-MS) is a powerful method for micro/nano-particle (MNP) sizing. Despite the outstanding evolution of the technique in the last decade, most studies still rely on traditional approaches based on (1) the use of integrated intensity as the analytical signal and (2) the calculation of the transport efficiency (TE). However, the increasing availability of MNP standards and advancements in hardware and software have unveiled new venues for MNP sizing, including TE-independent and time-based approaches. This work systematically examines these different methodologies to identify and summarize their strengths and weaknesses, thus helping to determine their preferred application areas.
Results
Different SP-ICP-MS methods for MNP sizing were assessed using AuNPs (20–70 nm) and SiO2MNPs (100–1000 nm). Among TE-dependent approaches, the particle frequency method was characterized by larger uncertainties than the particle size method. The results of the latter were dependent on the appropriate selection of the reference MNP, making the use of multiple reference MNPs recommended. TE-independent methods were based on external (linear and polynomial) calibrations and a relative approach. These methods exhibited the lowest uncertainties of all the strategies evaluated. External calibrations benefited from simpler calculations, but their application could be hindered by a lack of reference MNPs within the desired size range or by the need for interpolations outside the calibration range. Finally, transit time signals are directly proportional to the MNP size rather than its mass. The time-based method demonstrated adequate performance for sizing AuNPs but failed when sizing the largest SiO2MNPs (1000 nm).
Significance and novelty
This work provides further insights into the application of different SP-ICP-MS methodologies for MNP sizing. Both TE-independent approaches and the monitoring of the transit time as the analytical signal are underused strategies; in this context, a Python script was developed for accurate transit time measurement. After 20 years of development, a quantitative comparison of the different methodologies, including the most novel approaches, is deemed necessary for further growth on solid theoretical ground.
2023
Acker, Thibaut Van; Rua-Ibarz, Ana; Vanhaecke, Frank; Bolea-Fernandez, Eduardo
Laser Ablation for Nondestructive Sampling of Microplastics in Single-Particle ICP-Mass Spectrometry Journal Article
En: Anal. Chem., vol. 95, iss. 50, pp. 18579-18586, 2023.
@article{nokey,
title = {Laser Ablation for Nondestructive Sampling of Microplastics in Single-Particle ICP-Mass Spectrometry},
author = {Thibaut Van Acker and Ana Rua-Ibarz and Frank Vanhaecke and Eduardo Bolea-Fernandez},
url = {https://doi.org/10.1021/acs.analchem.3c04473},
doi = {10.1021/acs.analchem.3c04473},
year = {2023},
date = {2023-12-05},
urldate = {2023-12-05},
journal = {Anal. Chem.},
volume = {95},
issue = {50},
pages = {18579-18586},
abstract = {In this work, laser ablation (LA) was characterized as a method for sampling and introducing microplastic particles (MPs) into an inductively coupled plasma (ICP) for subsequent 13C+ monitoring using an ICP-mass spectrometer operated in single-event mode. MPs of different types (PS, PMMA, and PVC) and sizes (2–20 μm) were introduced intactly. The laser energy density did not affect the particle sampling across a wide range (0.25–6.00 J cm–2). Single-shot analysis separated clustered MPs (2–7 MPs per cluster) during the LA and particle transport processes, allowing the temporally resolved analysis of the individual constituting MPs. Line scanning showed superior performance when using a small laser beam diameter combined with a high repetition rate. The 13C+ signal intensity correlated linearly (R2 >0.9945) with the absolute C mass in a 2–10 μm size range, while the use of He in the collision-reaction cell (CRC) allowed extension of the linear range to 20 μm. The LA approach generated narrower 13C+ signal distributions than the traditional solution-based approach (dry versus wet plasma conditions) and proved successful for the analysis of a mixed suspension (containing four sizes of PS MPs in a 2–5 μm size range) and for sampling MPs from PVDF and glass microfiber filters, with the latter offering a lower background.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In this work, laser ablation (LA) was characterized as a method for sampling and introducing microplastic particles (MPs) into an inductively coupled plasma (ICP) for subsequent 13C+ monitoring using an ICP-mass spectrometer operated in single-event mode. MPs of different types (PS, PMMA, and PVC) and sizes (2–20 μm) were introduced intactly. The laser energy density did not affect the particle sampling across a wide range (0.25–6.00 J cm–2). Single-shot analysis separated clustered MPs (2–7 MPs per cluster) during the LA and particle transport processes, allowing the temporally resolved analysis of the individual constituting MPs. Line scanning showed superior performance when using a small laser beam diameter combined with a high repetition rate. The 13C+ signal intensity correlated linearly (R2 >0.9945) with the absolute C mass in a 2–10 μm size range, while the use of He in the collision-reaction cell (CRC) allowed extension of the linear range to 20 μm. The LA approach generated narrower 13C+ signal distributions than the traditional solution-based approach (dry versus wet plasma conditions) and proved successful for the analysis of a mixed suspension (containing four sizes of PS MPs in a 2–5 μm size range) and for sampling MPs from PVDF and glass microfiber filters, with the latter offering a lower background.
2021
Bolea-Fernandez, Eduardo; Rua-Ibarz, Ana; Resano, Martín; Vanhaecke, Frank
To shift, or not to shift: adequate selection of an internal standard in mass-shift approaches using tandem ICP-mass spectrometry (ICP-MS/MS) Journal Article
En: J. Anal. At. Spectrom., vol. 36, iss. 6, pp. 1135-1149, 2021.
@article{D0JA00438C,
title = {To shift, or not to shift: adequate selection of an internal standard in mass-shift approaches using tandem ICP-mass spectrometry (ICP-MS/MS)},
author = {Eduardo Bolea-Fernandez and Ana Rua-Ibarz and Martín Resano and Frank Vanhaecke},
url = {http://dx.doi.org/10.1039/D0JA00438C},
doi = {10.1039/D0JA00438C},
year = {2021},
date = {2021-01-01},
journal = {J. Anal. At. Spectrom.},
volume = {36},
issue = {6},
pages = {1135-1149},
publisher = {The Royal Society of Chemistry},
abstract = {The use of an internal standard to correct for potential matrix effects and instrument instability is common practice in ICP-MS. However, with the introduction of a new generation of ICP-MS instrumentation with a tandem mass spectrometry configuration (ICP-MS/MS), the use of chemical resolution in a mass-shift approach has become much more popular, suggesting that the appropriate selection of an internal standard needs revision. In this particular case, it needs to be decided whether the internal standard should also be subjected to a mass-shift or can simply be monitored on-mass (“to shift, or not to shift”). In this work, 17 elements covering a wide range of masses (24–205 amu) and ionization energies (3.89–9.39 eV) were measured via on-mass and/or mass-shift strategies, and the corresponding atomic ions and reaction product ions were monitored during various systematic experiments. For mass-shifting, an NH3/He gas mixture was used to obtain NH3-based reaction product ions (cluster formation). Product ion scanning (PIS) was used for assessing the differences in reactivity between the different analytes and for the identification of the best suited reaction product ions. It was found that the use of chemical resolution can significantly affect the short-term signal stability and that ion signals measured on-mass are not affected in the same way as those measured mass-shifted. Variations affecting the signal intensities of both atomic and reaction product ions can be attributed to the ion–molecule chemistry occurring within the collision/reaction cell and were found to be related with some degree of initial instability in the cell and differences in reactivity. The use of a sufficiently long stabilization time, however, avoids or at least mitigates such differences in the behavior between signals monitored on-mass and after mass-shifting, respectively. Furthermore, the introduction of cell disturbances, such as those generated after quickly switching between different sets of operating conditions in a multi-tune method, revealed significant differences in signal behavior between atomic and reaction product ions, potentially hampering the use of an internal standard monitored on-mass when the analysis is based on an analyte monitored after mass-shifting. However, the use of a reasonable waiting time again greatly mitigates such differences, with the duration of this stabilization time depending on the magnitude of the cell disturbances (e.g., switch between vented and pressurized mode or only between pressurized modes using different gas flow rates). In addition, also the effect of varying different instrument settings (plasma power, torch position, and gas and liquid flow rates) was evaluated, but no remarkable differences were found between signals monitored on-mass and those mass-shifted. Interestingly, a statistical evaluation of the influence of the different settings on the signal intensities of all ions monitored did not reveal the a priori important role of some properties traditionally suggested for adequate selection of analyte/internal standard pairs, such as mass number or ionization energy, as also suggested in other recent studies.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The use of an internal standard to correct for potential matrix effects and instrument instability is common practice in ICP-MS. However, with the introduction of a new generation of ICP-MS instrumentation with a tandem mass spectrometry configuration (ICP-MS/MS), the use of chemical resolution in a mass-shift approach has become much more popular, suggesting that the appropriate selection of an internal standard needs revision. In this particular case, it needs to be decided whether the internal standard should also be subjected to a mass-shift or can simply be monitored on-mass (“to shift, or not to shift”). In this work, 17 elements covering a wide range of masses (24–205 amu) and ionization energies (3.89–9.39 eV) were measured via on-mass and/or mass-shift strategies, and the corresponding atomic ions and reaction product ions were monitored during various systematic experiments. For mass-shifting, an NH3/He gas mixture was used to obtain NH3-based reaction product ions (cluster formation). Product ion scanning (PIS) was used for assessing the differences in reactivity between the different analytes and for the identification of the best suited reaction product ions. It was found that the use of chemical resolution can significantly affect the short-term signal stability and that ion signals measured on-mass are not affected in the same way as those measured mass-shifted. Variations affecting the signal intensities of both atomic and reaction product ions can be attributed to the ion–molecule chemistry occurring within the collision/reaction cell and were found to be related with some degree of initial instability in the cell and differences in reactivity. The use of a sufficiently long stabilization time, however, avoids or at least mitigates such differences in the behavior between signals monitored on-mass and after mass-shifting, respectively. Furthermore, the introduction of cell disturbances, such as those generated after quickly switching between different sets of operating conditions in a multi-tune method, revealed significant differences in signal behavior between atomic and reaction product ions, potentially hampering the use of an internal standard monitored on-mass when the analysis is based on an analyte monitored after mass-shifting. However, the use of a reasonable waiting time again greatly mitigates such differences, with the duration of this stabilization time depending on the magnitude of the cell disturbances (e.g., switch between vented and pressurized mode or only between pressurized modes using different gas flow rates). In addition, also the effect of varying different instrument settings (plasma power, torch position, and gas and liquid flow rates) was evaluated, but no remarkable differences were found between signals monitored on-mass and those mass-shifted. Interestingly, a statistical evaluation of the influence of the different settings on the signal intensities of all ions monitored did not reveal the a priori important role of some properties traditionally suggested for adequate selection of analyte/internal standard pairs, such as mass number or ionization energy, as also suggested in other recent studies.
2019
Bolea-Fernandez, Eduardo; Leite, Diego; Rua-Ibarz, Ana; Liu, Tong; Woods, Glenn; Aramendia, Maite; Resano, Martín; Vanhaecke, Frank
On the effect of using collision/reaction cell (CRC) technology in single-particle ICP-mass spectrometry (SP-ICP-MS) Journal Article
En: Analytica Chimica Acta, vol. 1077, pp. 95-106, 2019, ISSN: 0003-2670.
@article{BOLEAFERNANDEZ201995,
title = {On the effect of using collision/reaction cell (CRC) technology in single-particle ICP-mass spectrometry (SP-ICP-MS)},
author = {Eduardo Bolea-Fernandez and Diego Leite and Ana Rua-Ibarz and Tong Liu and Glenn Woods and Maite Aramendia and Martín Resano and Frank Vanhaecke},
url = {https://www.sciencedirect.com/science/article/pii/S0003267019306920},
doi = {https://doi.org/10.1016/j.aca.2019.05.077},
issn = {0003-2670},
year = {2019},
date = {2019-01-01},
journal = {Analytica Chimica Acta},
volume = {1077},
pages = {95-106},
abstract = {In this work, the effects of using collision/reaction cell (CRC) technology in quadrupole-based ICP-MS (ICP-QMS) instrumentation operated in single-particle (SP) mode have been assessed. The influence of (i) various CRC gases, (ii) gas flow rates, (iii) nanoparticle (NP) sizes and (iv) NP types was evaluated using Ag, Au and Pt NPs with both a traditional ICP-QMS instrument and a tandem ICP-mass spectrometer. It has been shown that using CRC technology brings about a significant increase in the NP signal peak width (from 0.5 up to 6 ms). This effect is more prominent for a heavier gas (e.g., NH3) than for a lighter one (e.g., H2 or He). At a higher gas flow rate and/or for larger particle sizes >100 nm), the NP signal duration was prolonged to a larger extent. This effect of using CRC technology has been further demonstrated by characterizing custom-made 50 and 200 nm Fe3O4 NPs (originally strongly affected by the occurrence of spectral overlap) using different CRC approaches (H2 on-mass and NH3 mass-shift). The use of NH3 (monitoring of Fe as the Fe(NH3)2+ reaction product ion at m/z = 90 amu) induces a significant peak broadening compared to that observed when using H2 (6.10 ± 1.60 vs. 0.94 ± 0.49 ms). This extension of transit time can most likely be attributed to the collisions/interactions of the ion cloud generated by a single NP event with the CRC gas and it even precludes 50 nm Fe3O4 NPs to be detected when using the NH3 mass-shift approach. Based on these results, the influence of a longer peak width on the accuracy of SP-ICP-MS measurement data (NP size, particle number density and mass concentration) must be taken into account when using CRC technology as a means to overcome spectral overlap. To mitigate the potential detrimental effect of using CRC technology in the characterization of NPs via SP-ICP-MS(/MS), the use of light gases and low gas flow rates is recommended.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In this work, the effects of using collision/reaction cell (CRC) technology in quadrupole-based ICP-MS (ICP-QMS) instrumentation operated in single-particle (SP) mode have been assessed. The influence of (i) various CRC gases, (ii) gas flow rates, (iii) nanoparticle (NP) sizes and (iv) NP types was evaluated using Ag, Au and Pt NPs with both a traditional ICP-QMS instrument and a tandem ICP-mass spectrometer. It has been shown that using CRC technology brings about a significant increase in the NP signal peak width (from 0.5 up to 6 ms). This effect is more prominent for a heavier gas (e.g., NH3) than for a lighter one (e.g., H2 or He). At a higher gas flow rate and/or for larger particle sizes >100 nm), the NP signal duration was prolonged to a larger extent. This effect of using CRC technology has been further demonstrated by characterizing custom-made 50 and 200 nm Fe3O4 NPs (originally strongly affected by the occurrence of spectral overlap) using different CRC approaches (H2 on-mass and NH3 mass-shift). The use of NH3 (monitoring of Fe as the Fe(NH3)2+ reaction product ion at m/z = 90 amu) induces a significant peak broadening compared to that observed when using H2 (6.10 ± 1.60 vs. 0.94 ± 0.49 ms). This extension of transit time can most likely be attributed to the collisions/interactions of the ion cloud generated by a single NP event with the CRC gas and it even precludes 50 nm Fe3O4 NPs to be detected when using the NH3 mass-shift approach. Based on these results, the influence of a longer peak width on the accuracy of SP-ICP-MS measurement data (NP size, particle number density and mass concentration) must be taken into account when using CRC technology as a means to overcome spectral overlap. To mitigate the potential detrimental effect of using CRC technology in the characterization of NPs via SP-ICP-MS(/MS), the use of light gases and low gas flow rates is recommended.
2017
Bolea-Fernandez, Eduardo; Leite, Diego; Rua-Ibarz, Ana; Balcaen, Lieve; Aramendía, Maite; Resano, Martín; Vanhaecke, Frank
Characterization of SiO2 nanoparticles by single particle-inductively coupled plasma-tandem mass spectrometry (SP-ICP-MS/MS) Journal Article
En: J. Anal. At. Spectrom., vol. 32, iss. 11, pp. 2140-2152, 2017.
@article{C7JA00138J,
title = {Characterization of SiO2 nanoparticles by single particle-inductively coupled plasma-tandem mass spectrometry (SP-ICP-MS/MS)},
author = {Eduardo Bolea-Fernandez and Diego Leite and Ana Rua-Ibarz and Lieve Balcaen and Maite Aramendía and Martín Resano and Frank Vanhaecke},
url = {http://dx.doi.org/10.1039/C7JA00138J},
doi = {10.1039/C7JA00138J},
year = {2017},
date = {2017-01-01},
journal = {J. Anal. At. Spectrom.},
volume = {32},
issue = {11},
pages = {2140-2152},
publisher = {The Royal Society of Chemistry},
abstract = {The increase in the use of SiO2 nanoparticles (NPs) is raising concern about their environmental and health effects, thus necessitating the development of novel methods for their straightforward detection and characterization. Single particle ICP-mass spectrometry (SP-ICP-MS) is able to provide information on the size of NPs, their particle number density and mass concentration. However, the determination of Si via ICP-MS is strongly hampered by the occurrence of spectral overlap from polyatomic species (e.g., CO+ and N2+). The use of tandem ICP-MS (ICP-MS/MS) enables interference-free conditions to be obtained, even in the most demanding applications. Upon testing several gases, the use of CH3F (monitoring of SiF+, mass-shift approach) and of H2 (monitoring of Si+, on-mass approach) were demonstrated to be the most suitable to overcome the spectral interference affecting ultra-trace Si determination (LoD < 15 ng L−1). By using these approaches, SiO2 NPs (ranging between 80 and 400 nm) can be detected and characterized. For SiO2 NPs > 100 nm, it was possible to provide accurate results in a straightforward way, as the signals they give rise to are well resolved from those of the background. In the case of 80 and 100 nm NPs, the use of a simple deconvolution approach following a Gaussian model was needed to characterize SiO2 NPs apparently showing incomplete distributions as a result of the presence of the background signal. Overall, the methods developed using SP-ICP-MS/MS are sensitive and selective enough for the interference-free determination of Si at ultra-trace levels, also in the form of SiO2 NPs.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The increase in the use of SiO2 nanoparticles (NPs) is raising concern about their environmental and health effects, thus necessitating the development of novel methods for their straightforward detection and characterization. Single particle ICP-mass spectrometry (SP-ICP-MS) is able to provide information on the size of NPs, their particle number density and mass concentration. However, the determination of Si via ICP-MS is strongly hampered by the occurrence of spectral overlap from polyatomic species (e.g., CO+ and N2+). The use of tandem ICP-MS (ICP-MS/MS) enables interference-free conditions to be obtained, even in the most demanding applications. Upon testing several gases, the use of CH3F (monitoring of SiF+, mass-shift approach) and of H2 (monitoring of Si+, on-mass approach) were demonstrated to be the most suitable to overcome the spectral interference affecting ultra-trace Si determination (LoD < 15 ng L−1). By using these approaches, SiO2 NPs (ranging between 80 and 400 nm) can be detected and characterized. For SiO2 NPs > 100 nm, it was possible to provide accurate results in a straightforward way, as the signals they give rise to are well resolved from those of the background. In the case of 80 and 100 nm NPs, the use of a simple deconvolution approach following a Gaussian model was needed to characterize SiO2 NPs apparently showing incomplete distributions as a result of the presence of the background signal. Overall, the methods developed using SP-ICP-MS/MS are sensitive and selective enough for the interference-free determination of Si at ultra-trace levels, also in the form of SiO2 NPs.