Abstract The field of nanoscience and nanotechnology is continuously growing, providing Society w... more Abstract The field of nanoscience and nanotechnology is continuously growing, providing Society with novel nanomaterials enabling applications in different strategic sectors (industry, environment, energy, medicine, food, etc.) that improve the quality of life for humans. In this context, precise control of the quality and physicochemical properties offered by new materials is mandatory to ensure a successful application. Moreover, the effects of these man-made nanomaterials on the environment and health are still under study and, so, the safety of such novel materials is a current concern. Eventual properties and effects strongly depend on the characteristics of the nanomaterial (e.g., size, shape, chemical composition, and surface state). Thus, appropriate physicochemical methodologies for the characterization of nanomaterials are strongly demanded. In this chapter mass spectrometry (MS) tools and approaches used for the characterization of gold nanoparticles (AuNPs) are critically summarized. The continuous evolution of MS techniques employed for AuNP analysis is presented.
One of the major challenges in developing novel assay methods for the detection of biomolecules i... more One of the major challenges in developing novel assay methods for the detection of biomolecules is achieving high sensitivity, because of the ultralow concentrations typically in clinical samples. Here, a Mn-doped ZnS quantum dots-based immunoassay platform is presented for highly sensitive detection of cancer biomarkers. Ultrahigh sensitivity is achieved through gold deposition on the surface of the nanoparticle tags acting as catalytic seeds, thus effectively amplifying the size of the metallic nanoparticles after the immunoassay and before the tag detection. Elemental mass spectrometry measurement of the gold content allowed detection of Prostate-Specific Antigen (PSA) at the low attog mL(-1) level. Moreover, the developed method showed not only an extremely high sensitivity for PSA detection but also a broad dynamic range, higher than 8 orders of magnitude, particularly useful for clinical studies involving quantitative detection of diverse biomarkers at their very different relevant concentration levels. Its applicability to discriminate small differences in PSA concentrations at low levels (few pgmL(-1)) in real serum samples was successfully evaluated.
A methodology for the determination of butyltin compounds by isotope dilution mass spectrometry b... more A methodology for the determination of butyltin compounds by isotope dilution mass spectrometry based on a triple spike approach is presented. A spike solution containing monobutyltin, dibutyltin and tributyltin, each compound enriched with different tin isotopes, has been synthesised, ...
A comparative study of the cytotoxicity of HgSe nanoparticles and that induced by inorganic mercu... more A comparative study of the cytotoxicity of HgSe nanoparticles and that induced by inorganic mercury and methylmercury in two cell lines.
A sheathless interface based on a total consumption micronebulizer operating at flow rates in the... more A sheathless interface based on a total consumption micronebulizer operating at flow rates in the range 0.5-7.5 microL min(-1) was developed between capillary HPLC and ICPMS. It allowed the efficient nebulization and transport into the plasma of mobile phases containing up to 100% organic solvent without either cooling the spray chamber or oxygen addition. The coupled system was applied to selenopeptide mapping in a protein fraction isolated from a selenized yeast extract. The detection limits were 150 (80Se) and 200 fg (82Se) for a quadrupole instrument with and without a collision cell, respectively, which is a factor 100-150 less than that reported elsewhere for HPLC-ICPMS. The minimal peak broadening ( approximately 5 s at the half-height) allowed baseline resolution of a mixture containing more than 30 selenopeptides, many of which could not be separated using the conventional HPLC-ICPMS coupling.
Advances in analytical methodology for speciation of selenium in selenized-yeast food supplements... more Advances in analytical methodology for speciation of selenium in selenized-yeast food supplements were discussed on the basis of the recent developments in the authors' laboratory. Particular attention was given to the sample preparation with regard to the fractionation of selenium ...
The potential of tandem mass spectrometry following matrix-assisted laser desorption ionization (... more The potential of tandem mass spectrometry following matrix-assisted laser desorption ionization (MALDI) was studied for speciation of selenium. Non-peptide selenium-containing compounds were isolated from a selenized yeast aqueous extract by size-exclusion chromatography. Post-source decay (PSD) was compared with orthogonal quadrupole collision cell dissociation for the purpose of obtaining fragmentation and structural information. In the PSD mode, the use of ion gate covering the whole isotopic cluster of the parent compound allowed the immediate recognition of fragments containing Se and those in which this element was absent. The tandem mass spectra obtained by orthogonal MALDI Q-TOF were equally informative in terms of the number of fragments but suffered from a poorer sensitivity. The mass accuracy was ca. 20 times better in the oMALDI configuration than in the PSD mode. An unknown selenium compound with an m/z 388 was detected with a mass accuracy of 3 ppm according to the proposed empiric formula.
Abstract The field of nanoscience and nanotechnology is continuously growing, providing Society w... more Abstract The field of nanoscience and nanotechnology is continuously growing, providing Society with novel nanomaterials enabling applications in different strategic sectors (industry, environment, energy, medicine, food, etc.) that improve the quality of life for humans. In this context, precise control of the quality and physicochemical properties offered by new materials is mandatory to ensure a successful application. Moreover, the effects of these man-made nanomaterials on the environment and health are still under study and, so, the safety of such novel materials is a current concern. Eventual properties and effects strongly depend on the characteristics of the nanomaterial (e.g., size, shape, chemical composition, and surface state). Thus, appropriate physicochemical methodologies for the characterization of nanomaterials are strongly demanded. In this chapter mass spectrometry (MS) tools and approaches used for the characterization of gold nanoparticles (AuNPs) are critically summarized. The continuous evolution of MS techniques employed for AuNP analysis is presented.
One of the major challenges in developing novel assay methods for the detection of biomolecules i... more One of the major challenges in developing novel assay methods for the detection of biomolecules is achieving high sensitivity, because of the ultralow concentrations typically in clinical samples. Here, a Mn-doped ZnS quantum dots-based immunoassay platform is presented for highly sensitive detection of cancer biomarkers. Ultrahigh sensitivity is achieved through gold deposition on the surface of the nanoparticle tags acting as catalytic seeds, thus effectively amplifying the size of the metallic nanoparticles after the immunoassay and before the tag detection. Elemental mass spectrometry measurement of the gold content allowed detection of Prostate-Specific Antigen (PSA) at the low attog mL(-1) level. Moreover, the developed method showed not only an extremely high sensitivity for PSA detection but also a broad dynamic range, higher than 8 orders of magnitude, particularly useful for clinical studies involving quantitative detection of diverse biomarkers at their very different relevant concentration levels. Its applicability to discriminate small differences in PSA concentrations at low levels (few pgmL(-1)) in real serum samples was successfully evaluated.
A methodology for the determination of butyltin compounds by isotope dilution mass spectrometry b... more A methodology for the determination of butyltin compounds by isotope dilution mass spectrometry based on a triple spike approach is presented. A spike solution containing monobutyltin, dibutyltin and tributyltin, each compound enriched with different tin isotopes, has been synthesised, ...
A comparative study of the cytotoxicity of HgSe nanoparticles and that induced by inorganic mercu... more A comparative study of the cytotoxicity of HgSe nanoparticles and that induced by inorganic mercury and methylmercury in two cell lines.
A sheathless interface based on a total consumption micronebulizer operating at flow rates in the... more A sheathless interface based on a total consumption micronebulizer operating at flow rates in the range 0.5-7.5 microL min(-1) was developed between capillary HPLC and ICPMS. It allowed the efficient nebulization and transport into the plasma of mobile phases containing up to 100% organic solvent without either cooling the spray chamber or oxygen addition. The coupled system was applied to selenopeptide mapping in a protein fraction isolated from a selenized yeast extract. The detection limits were 150 (80Se) and 200 fg (82Se) for a quadrupole instrument with and without a collision cell, respectively, which is a factor 100-150 less than that reported elsewhere for HPLC-ICPMS. The minimal peak broadening ( approximately 5 s at the half-height) allowed baseline resolution of a mixture containing more than 30 selenopeptides, many of which could not be separated using the conventional HPLC-ICPMS coupling.
Advances in analytical methodology for speciation of selenium in selenized-yeast food supplements... more Advances in analytical methodology for speciation of selenium in selenized-yeast food supplements were discussed on the basis of the recent developments in the authors' laboratory. Particular attention was given to the sample preparation with regard to the fractionation of selenium ...
The potential of tandem mass spectrometry following matrix-assisted laser desorption ionization (... more The potential of tandem mass spectrometry following matrix-assisted laser desorption ionization (MALDI) was studied for speciation of selenium. Non-peptide selenium-containing compounds were isolated from a selenized yeast aqueous extract by size-exclusion chromatography. Post-source decay (PSD) was compared with orthogonal quadrupole collision cell dissociation for the purpose of obtaining fragmentation and structural information. In the PSD mode, the use of ion gate covering the whole isotopic cluster of the parent compound allowed the immediate recognition of fragments containing Se and those in which this element was absent. The tandem mass spectra obtained by orthogonal MALDI Q-TOF were equally informative in terms of the number of fragments but suffered from a poorer sensitivity. The mass accuracy was ca. 20 times better in the oMALDI configuration than in the PSD mode. An unknown selenium compound with an m/z 388 was detected with a mass accuracy of 3 ppm according to the proposed empiric formula.
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Papers by Jorge Encinar