Filtern
Erscheinungsjahr
Dokumenttyp
- Zeitschriftenartikel (91)
- Vortrag (68)
- Sonstiges (9)
- Buchkapitel (4)
- Posterpräsentation (4)
- Beitrag zu einem Sammelband (1)
Schlagworte
- ICP-MS (30)
- Laser ablation (16)
- Nanoparticles (15)
- LA-ICP-MS (14)
- Cell (11)
- Nanoparticle (8)
- Bioimaging (7)
- Speciation (7)
- Imaging (6)
- Mass cytometry (5)
Organisationseinheit der BAM
Eingeladener Vortrag
- nein (68)
The successful off-line coupling of asymmetrical flow field flow fractionation (AF4) and capillary electrophoresis (CE) for separation of nanoparticles (NPs) with different surface coatings was shown. We could successfully demonstrate that, in a certain NP size range, hyphenation of both techniques significantly improved the separation of differently coated NPs. Three mixtures of polystyrene nanoparticles (PS-NPs) with comparable core sizes but different coatings (no coating/carboxyl-coated) were studied. Separation in either method resulted in non-baseline resolved or non-separated peaks. In contrast, two-dimensional off-line coupling of AF4 and CE resulted in clearly separated regions in their 2 D plots in case of 20 and 50 nm particle mixtures, whereas the 100 nm NP mixture could not be separated at all. Various factors affecting the separation like hydrodynamic diameter or SDS concentration were discussed.
In this paper, we describe the labelling of antibodies by gold nanoparticles (AuNPs) with diameters of 10 and 60 nm with detection by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Additionally, the AuNPs labelling strategy is compared with commercially available labelling reagents based on MeCAT (metal coded affinity tagging). Proof of principle experiments based on dot blot experiments were performed. The two labelling methods investigated were compared by sensitivity and limit of detection (LOD). The absolute LODs achieved were in the range of tens of picograms for AuNP labelling compared to a few hundred picograms by the MeCAT labelling.
Complementarity of molecular and elemental mass spectrometric imaging of Gadovist™ in mouse tissues
(2019)
Drug biodistribution analyses can be considered a key issue in pharmaceutical discovery and development. Here, mass spectrometric imaging can be employed as a powerful tool to investigate distributions of drug compounds in biologically and medically relevant tissue sections. Both matrix-assisted laser desorption ionization–mass spectrometric imaging as molecular method and laser ablation inductively coupled plasma–mass spectrometric imaging as elemental detection method were applied to determine drug distributions in tissue thin sections. Several mouse organs including the heart, kidney, liver, and brain were analyzed with regard to distribution of Gadovist™, a gadolinium-based contrast agent already approved for clinical investigation. This work demonstrated the successful detection and localization of Gadovist™ in several organs. Furthermore, the results gave evidence that gadolinium-based contrast agents in general can be well analyzed by mass spectrometric imaging methods. In conclusion, the combined application of molecular and elemental mass spectrometry could complement each other and thus confirm analytical results or provide additional information.
This tutorial review article is highlighting the fundamentals, instrumentation, and most recent trends of single-cell analysis by use of inductively coupled plasma-mass spectrometry (ICP-MS). It is shown that metals and hetero-elements being intrinsically present in cells, taken up by cells (for instance engineered metallic nanoparticles) or binding to a cell can be detected qualitatively by existing ICP-MS Technologies on a single cell level. Adding a quantitative dimension to single-cell analysis by (laser ablation-) ICP-MS requires dedicated calibration and validation strategies, which are currently being established and are being critically discussed. In a tutorial part, the ICP-MS instruments, the measurement conditions, and the sample introduction and preparation techniques are introduced. The application section focuses on the state-of-the-art of single-cell analysis in suspension, using laser ablation or (imaging) mass cytometry. Finally, future trends are critically assessed.
Inductively coupled plasma mass spectrometry (ICP-MS) is based on formation of positively charged atomic ions in a high-frequency inductively coupled Argon plasma at atmospheric pressure. The ions are extracted and transferred from the plasma source into a mass analyzer operated at high vacuum via an interface equipped with a sampling and a skimmer cone. The ions are separated in the mass analyzer according to their charge to mass ratio. The ions are converted at a conversion dynode and are detected by use of a secondary electron multiplier or a Faraday cup.
From an analytical point of view, ICP-MS is a well-established method for multi-elemental analysis in particular for elements at trace- and ultra-trace levels. Furthermore, methods based on ICP-MS offer simple quantification concepts, for which usually (liquid) standards are applied, low matrix effects compared to other conventional analytical techniques, and relative limits of detection (LODs) in the low pg g−1 range and absolute LODs down to the attomol range. For these applications, ICP-MS excels by a high sensitivity which is independent of the molecular structure and a wide linear dynamic range. It has found acceptance in various application areas and during the last decade ICP-MS is also more and more applied for detection of rare earth elements particularly in the life sciences.
Due to the fact that all molecules introduced into the high temperature of the plasma in the ion source were completely dissociated and broken down into atoms, which are subsequently ionized, all elemental species information is completely lost. However, if the different species are separated before they enter the plasma by using adequate fractionation or separation techniques, then ICP-MS can be used as a very sensitive element-specific detector. We will discuss this feature of ICP-MS in this chapter in more detail at hand of the speciation of gadolinium-containing contrast agents.
Inductively coupled plasma mass spectrometry (ICP-MS) is based on formation of positively charged atomic ions in a high-frequency inductively coupled Argon plasma at atmospheric pressure. The ions are extracted and transferred from the plasma source into a mass analyzer operated at high vacuum via an interface equipped with a sampling and a skimmer cone. The ions are separated in the mass analyzer according to their charge to mass ratio. The ions are converted at a conversion dynode and are detected by use of a secondary electron multiplier or a Faraday cup.
From an analytical point of view, ICP-MS is a well-established method for multi-elemental analysis in particular for elements at trace- and ultra-trace levels. Furthermore, methods based on ICP-MS offer simple quantification concepts, for which usually (liquid) standards are applied, low matrix effects compared to other conventional analytical techniques, and relative limits of detection (LODs) in the low pg g−1 range and absolute LODs down to the attomol range. For these applications, ICP-MS excels by a high sensitivity which is independent of the molecular structure and a wide linear dynamic range. It has found acceptance in various application areas and during the last decade ICP-MS is also more and more applied for detection of rare earth elements particularly in the life sciences.
Due to the fact that all molecules introduced into the high temperature of the plasma in the ion source were completely dissociated and broken down into atoms, which are subsequently ionized, all elemental species information is completely lost. However, if the different species are separated before they enter the plasma by using adequate fractionation or separation techniques, then ICP-MS can be used as a very sensitive element-specific detector. We will discuss this feature of ICP-MS in this chapter in more detail at hand of the speciation of gadolinium-containing contrast agents.
A reversed phase high performance liquid chromatography coupled to an inductively coupled plasma mass spectrometer (HPLC-ICP-MS) approach in combination with isotope dilution analysis (IDA) for the separation and parallel quantification of nanostructured and ionic silver (Ag) is presented. The main focus of this work was the determination of the ionic Ag concentration. For a sufficient stabilization of the ions without dissolving the nanoparticles (NPs), the eluent had to be initially optimized. The determined Ag ion concentration was in a good agreement with results obtained using ultrafiltration. Further, the mechanism of the NP separation in the HPLC column was investigated. Typical size exclusion effects were found by comparing results from columns with different pore sizes. Since the recovery rates decreased with increasing Ag NP size and large Ag NPs did not elute from the column, additional interactions of the particles with the stationary phase were assumed. Our results reveal that the presented method is not only applicable to Ag NPs, but also to gold and polystyrene NPs. Finally, IDA-HPLC-ICP-MS experiments in single particle mode were performed to determine the particle cut-off size. The comparison with conventional spICP-MS experiments resulted in a similar diameter and particle size distribution.
In this work, sample losses of silver nanoparticles (Ag NPs) in asymmetrical flow field-flow fractionation (AF4) have been systematically investigated with the main focus on instrumental conditions like focusing and cross-flow parameters as well as sample concentration and buffer composition. Special attention was drawn to the AF4 membrane. For monitoring possible silver depositions on the membrane, imaging laser ablation coupled to inductively coupled plasma mass spectrometry (LA-ICP-MS) was used. Our results show that the sample residue on the membrane was below 0.6% of the total injected amount and therefore could be almost completely avoided at low sample concentrations and optimized conditions. By investigation of the AF4 flows using inductively coupled plasma mass spectrometry (ICP-MS), we found the recovery rate in the detector flow under optimized conditions to be nearly 90%, while the cross-flow, slot-outlet flow and purge flow showed negligible amounts of under 0.5%. The analysis of an aqueous ionic Ag standard solution resulted in recovery rates of over 6% and the ionic Ag content in the sample was found to be nearly 8%. Therefore, we were able to indicate the ionic Ag content as the most important source of sample loss in this study.
A reversed phase high performance liquid chromatography coupled to an inductively coupled Plasma mass spectrometer (HPLC–ICP-MS) approach in combination with isotope dilution analysis (IDA) for the separation and parallel quantification of nanostructured and ionic silver (Ag) is presented. The main Focus of this work was the determination of the ionic Ag concentration. For a sufficient stabilization of the Ions without dissolving the nanoparticles (NPs), the eluent had to be initially optimized. The determined Ag ion concentration was in a good agreement with results obtained using ultrafiltration. Further, the mechanism of the NP separation in the HPLC column was investigated. Typical size exclusion effects were found by comparing results from columns with different pore sizes. Since the recovery rates decreased with increasing Ag NP size and large Ag NPs did not elute from the column, additional interactions of the particles with the stationary phase were assumed. Our results reveal that the presented method is not only applicable to Ag NPs, but also to gold and polystyrene NPs. Finally, IDA-HPLC-ICP-MS experiments in single particle mode were performed to determine the particle cut-off size. The comparison with conventional spICP-MS experiments resulted in a similar diameter and particle size distribution.
Single particle ICP-MS (spICP-MS) has gained great influence in the analysis of engineered nanoparticles (NPs) due to its simplicity, speed and ability to obtain a particle number size distribution. Despite its many advantages, the method is hampered by matrix effects affecting the sensitivity of the instruments.
Consequently, over- or underestimated particle sizes might be obtained. To overcome these challenges, we present in this work the detection of both Ag isotopes with a quadrupole mass spectrometer for the application of isotopic dilution analysis (IDA) in combination with spICP-MS. Here, the isotopes are measured sequentially using the conventional spICP-MS integration time of 10 ms. Citrate stabilized Ag NPs of a spherical shape with the nominal diameters of 30, 40, 50 and 80 nm have been investigated.
The experimental concept of adding ¹⁰⁹Ag+ solutions to the NP suspensions resulted in the NP Spikes being only visible in the ¹⁰⁷Ag trace. Therefore, a maximum of 45% of the particles was detected compared to that by conventional spICP-MS. A modified mass flow equation was applied to determine the particle sizes, particle size distributions and particle number concentrations of various Ag NPs. The addition of different spike concentrations between 0.5 and 4 mg L⁻¹ ¹⁰⁹Ag resulted in similar particle diameters, suggesting that the calculated diameter might be independent of the spike concentration.
This would have the advantage that no size information would be needed before the analysis. By analyzing Ag NP suspensions in a simulated seawater matrix, we demonstrate its significant influence on the particle size determination using conventional spICP-MS. A lower transport efficiency of 6.1% was found in the matrix compared to 7.3% without the matrix. In our approach, the addition of the Matrix influenced the NP intensity stronger than the spike signal, resulting in slightly smaller diameters using IDA–spICP-MS with the matrix compared to the results without the matrix. On the other hand, the IDA–spICP-MS approach with the matrix can result in equivalent results for the particle sizes compared with
conventional spICP-MS using suspensions without the matrix. Due to the lower instrument sensitivity in the matrix, a diameter of 30 nm was found to be close to the detection limit of the instrument.