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ICP-MS is based on the formation of (preferentially monovalent positively)charged atomic ions in an inductively coupled Ar plasma at almost 10 000 K. The ions formed are transferred from the plasma source at ambient pressure into a mass Separator operated at high vacuum via a set of cones. The ions are separate«! according to their mass/charge ratio in the mass Separator (quadrupole, magnetic sector field or time-of-flight mass Separator). In most cases, the ions are detected using a secondaiy electron multiplier; in some set-ups (also) a Faraday cup can be used. Single-collector (scanning mass spectrometer usually used for quantitative elemental analysis) or multicollector (static Operation of mass spectrometer for precise isotope ratio analysis) configurations can be found.
In this work, a routinely applicable approach is presented to characterize metal NPs. Individual droplets generated from a microdroplet generator (MDG) were merged into an aerosol generated by a pneumatic nebulizer (PN) and introduced into an ICPMS. The MDG offers high transport efficiency of individual and discrete droplets and was therefore used to establish a calibration function for mass quantification of NPs which were introduced through the PN following the single particle procedure as described elsewhere. The major advantages of such a combined configuration include fast processing of large sample volumes, fast exchanges of different sample matrixes, and the calibration of the NP signal using traceable elemental standards, thus avoiding the need to use NP reference materials or other, not always thoroughly characterized, commercially available NPs. The transport efficiency of the sample introduction is calculated based on the fact that 100% of the calibrant reaches the plasma through the MDG, whereas for the PN a NP suspension containing a known number concentration is used. Alternatively, bulk analysis of the NP material allows transport efficiency determination without any additional information from reference NPs. With this method, we could determine the size of standard silver NPs at 60.4 ± 1.0 nm and 80.0 ± 1.4 nm, respectively, which agrees with the size ranges given by the supplier (60.8 ± 6.6 nm and 79.8 ± 5.4 nm). Furthermore, we were also able to determine the NPs number concentration of the sample (Ag/Au) with a deviation of 3.2% the expected value.
Tributyltin is listed as one of the priority substances in the European Water Framework Directive (WFD). Despite its decreasing input in the environment, it is still present and has to be monitored. In the European Metrology Research Programme project ENV08, a sensitive and reliable analytical method according to the WFD was developed to quantify this environmental pollutant at a very low limit of quantification. With the development of such a primary reference method for tributyltin, the project helped to improve the quality and comparability of monitoring data. An overview of project aims and potential analytical tools is given.
Inductively coupled plasma mass spectrometry (ICP-MS) is a well-established analytical method for multi-elemental analysis in particular for elements at trace and ultra-trace levels. It has found acceptance in various application areas during the last decade. ICP-MS is also more and more applied for detection in the life sciences. For these applications, ICP-MS excels by a high sensitivity, which is independent of the molecular structure of the analyte, a wide linear dynamic range and by excellent multi-element capabilities. Furthermore, methods based on ICP-MS offer simple quantification concepts, for which usually (liquid) standards are applied, low matrix effects compared to other conventional bioanalytical techniques, and relative limits of detection (LODs) in the low pg g−1 range and absolute LODs down to the attomol range.
In this chapter, we focus on new applications where the multi-element capability of ICP-MS is used for detection of lanthanoides or rare earth elements, which are applied as elemental stains or tags of biomolecules and in particular of antibodies.
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.
Inductively coupled plasma mass spectrometry (ICP-MS) is a well-established analytical method for multi-elemental analysis in particular for elements at trace and ultra-trace levels. It has found acceptance in various application areas during the last decade. ICP-MS is also more and more applied for detection in the life sciences. For these applications, ICP-MS excels by a high sensitivity, which is independent of the molecular structure of the analyte, a wide linear dynamic range and by excellent multi-element capabilities. Furthermore, methods based on ICP-MS offer simple quantification concepts, for which usually (liquid) standards are applied, low matrix effects compared to other conventional bioanalytical techniques, and relative limits of detection (LODs) in the low pg g−1 range and absolute LODs down to the attomol range.
In this chapter, we focus on new applications where the multi-element capability of ICP-MS is used for detection of lanthanoides or rare earth elements, which are applied as elemental stains or tags of biomolecules and in particular of antibodies.
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been revealed as a convenient technique for trace elemental imaging in tissue sections, providing elemental 2D distribution at a quantitative level. For quantification purposes, in the last years several approaches have been proposed in the literature such as the use of CRMs or matrix matched standards. The use of Isotope Dilution (ID) for quantification by LA-ICP-MS has been also described, being mainly useful for bulk analysis but not feasible for spatial measurements so far. In this work, a quantification method based on ID analysis was developed by printing isotope-enriched inks onto kidney slices from rats treated with antitumoral Pt-based drugs using a commercial ink-jet device, in order to perform an elemental quantification in different areas from bio-images. For the ID experiments ¹⁹⁴Pt enriched platinum was used. The methodology was validated by deposition of natural Pt standard droplets with a known amount of Pt onto the surface of a control tissue, where could be quantified even 50 pg of Pt, with recoveries higher than 90%. The amount of Pt present in the whole kidney slices was quantified for cisplatin, carboplatin and oxaliplatin-treated rats. The results obtained were in accordance with those previously reported. The amount of Pt distributed between the medullar and cortical areas was also quantified, observing different behavior for the three drugs.
Quantification of nanoparticle (NP) uptake in cells or tissues is very important for safety assessment. Often, electron microscopy based approaches are used for this purpose, which allow imaging at very high resolution. However, precise quantification of NP numbers in cells and tissues remains challenging. The aim of this study was to present a novel approach, that combines precise quantification of NPs in individual cells together with high resolution imaging of their intracellular distribution based on focused ion beam/ scanning electron microscopy (FIB/SEM) slice and view approaches.
Metalloproteins, which represent about 30 % of the total proteome, are often important markers for distinguishing between healthy and diseased states of patients. As such markers have become increasingly important in clinical diagnostics, some of these proteins are routinely analysed in clinical laboratories. Reliable and comparable results are the basis for the investigation of changes in the proteome due to different health conditions. Nevertheless, for many proteins the results achieved with different routine measurement procedures or in different laboratories vary widely, thus hampering medical insights and the development of treatments. Reference measurement procedures with results traceable to the International System of Units (SI) will also help to greatly improve the performance of routine measurement procedures and, this way, they support the understanding of changes in the metallome.
Short course on ICP-MS
(2017)
ICP-MS is a well-established analytical method which excels by high accuracy, high dynamic range and extremely low limits of detection for most metals. Furthermore ICP-MS offers a very high multi-element coverage so that many elements of the periodic table can be detected simultaneously. In this series of lectures, we want to focus on the historical developments, fundamentals, instrumentation and novel applications of ICP-MS in the life and material sciences.
Lecture 7: Speciation
(2017)
ICP-MS is a well-established analytical method which excels by high accuracy, high dynamic range and extremely low limits of detection for most metals. Furthermore ICP-MS offers a very high multi-element coverage so that many elements of the periodic table can be detected simultaneously. In this series of lectures, we want to focus on the historical developments, fundamentals, instrumentation and novel applications of ICP-MS in the life and material sciences.
Spectral interferences
(2017)
ICP-MS is a well-established analytical method which excels by high accuracy, high dynamic range and extremely low limits of detection for most metals. Furthermore ICP-MS offers a very high multi-element coverage so that many elements of the periodic table can be detected simultaneously. In this series of lectures, we want to focus on the historical developments, fundamentals, instrumentation and novel applications of ICP-MS in the life and material sciences.
Non-spectral interferences
(2017)
ICP-MS is a well-established analytical method which excels by high accuracy, high dynamic range and extremely low limits of detection for most metals. Furthermore ICP-MS offers a very high multi-element coverage so that many elements of the periodic table can be detected simultaneously. In this series of lectures, we want to focus on the historical developments, fundamentals, instrumentation and novel applications of ICP-MS in the life and material sciences.
Gold nanostructures that serve as probes for nanospectroscopic analysis of eukaryotic cell cultures can be obtained by the in situ reduction of tetrachloroauric acid (HAuCl4). To understand the formation process of such intracellularly grown particles depending on the incubation medium, the reaction was carried out with 3T3 fibroblast cells in three different incubation media, phosphate buffer, Dulbecco's Modified Eagle Medium (DMEM), and standard cell culture medium (DMEM with fetal calf serum). The size, the optical properties, the biomolecular corona, and the localization of the gold nanoparticles formed in situ vary for the different conditions. The combination of surface-enhanced Raman scattering (SERS) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) microscopic mapping and transmission electron microscopy (TEM) provides complementary perspectives on plasmonic nanoparticles and non-plasmonic gold compounds inside the cells. While for the incubation with HAuCl4 in PBS, gold particles provide optical signals from the nucleus, the incubation in standard cell culture medium leads to scavenging of the toxic molecules and the formation of spots of high gold concentration in the cytoplasm without formation of SERS-active particles inside the cells. The biomolecular corona of nanoparticles formed in situ after incubation in buffer and DMEM differs, suggesting that different intracellular molecular species serve for reduction and stabilization. Comparison with data obtained from ready-made gold nanoparticles suggests complementary application of in situ and ex situ generated nanostructures for optical probing.
ICP-MS is a well-established analytical method which excels by high accuracy, high dynamic range and extremely low limits of detection for most metals. Furthermore ICP-MS offers a very high multi-element coverage so that many elements of the periodic table can be detected simultaneously. In this series of lectures, we want to focus on the historical developments, fundamentals, instrumentation and novel applications of ICP-MS in the life and material sciences.
Single-particle inductively coupled plasma mass spectrometry (sp-ICP-MS) has become an effective tool for the detection and quantification of inorganic nanoparticles (NPs). While sizing of NPs suspended in water is relatively straightforward by sp-ICP-MS, accurate mass quantification of NPs in complex media, such as consumer products and natural systems still remains a challenge. When NPs are suspended in a complex medium, the matrix may affect the analyte sensitivity and lead to inaccurate NP sizing. Here, we investigate the use of an online microdroplet calibration system to size NPs in a single step. In this setup, microdroplets—which are used as the calibrant to determine elemental sensitivities—and nebulized NP-containing solutions are introduced concurrently into the ICP via a dual-inlet sample introduction system. Because calibrant microdroplets and analyte NPs experience the same plasma conditions, both the microdroplets and the NPs are subjected to the same matrix-related signal enhancement or suppression. In this way, the microdroplet calibration standards are automatically matrix matched with the NP-containing solution. The online microdroplet calibration system is combined with an ICP-TOFMS instrument for simultaneous measurement of multiple elements in microdroplets and NPs. We investigate the ability of online microdroplet calibration to compensate for matrix effects through a series of experiments, in which Ag and Au NPs are measured with variable plasma-sampling positions, varying concentrations of HCl and HNO3, varying concentrations of single element solutions, and high concentrations of a salt matrix, i.e. phosphate buffered saline (PBS). Through these experiments, we demonstrate that the online microdroplet calibration strategy provides a matrix-independent mass quantification of analyte NPs in the presence of several established types of matrix effects, including acid effects, space-charge effects, and ionisation suppression. In results presented here, we focus on the size determination of the NPs.
We have efficiently produced collagen-rich microstructures in fibroblast multicellular spheroids (MCSs) as a three-dimensional in vitro tissue analog to investigate silver (Ag) nanoparticle (NP) penetration. The MCS production was examined by changing the seeding cell number (500 to 40,000 cells) and the growth period (1 to 10 days). MCSs were incubated with Ag NP suspensions with a concentration of 5 μg/mL for 24 h. For this study, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used to visualize Ag NP localization quantitatively. Thin sections of MCSs were analyzed by LA-ICP-MS with a laser spot size of 8 μm to image distributions of 109Ag, 31P, 63Cu, 66Zn, and 79Br. A calibration using a NP suspension was applied to convert the measured Ag intensity into the number of NPs present. The determined numbers of NPs ranged from 30 to 7200 particles in an outer rim of MCS. The particle distribution was clearly correlated with the presence of 31P and 66Zn and was localized in the outer rim of proliferating cells with a width that was equal to about twice the diameter of single cells. Moreover, abundant collagens were found in the outer rim of MCSs. For only the highest seeding cell number, NPs were completely captured at the outer rim, in a natural barrier reducing particle transport, whereas Eosin (79Br) used as a probe of small molecules penetrated into the core of MCSs already after 1 min of exposure.