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Two types of copper samples, compact certified copper reference materials and calibration samples prepared from liquid doped, pressed copper powders, were studied in terms of accuracy of obtained calibration functions originating from infrared spark ablation. Additionally, corresponding particle size distributions of the aerosols from infrared spark ablation were recorded. It is shown that the differences in quantification results, originating from the two sets of calibration functions, could not mainly be ascribed to different particle size distributions of the two copper sample types. Possible other causes, as different ablation rates, parts of melting and differences of the chemical constitutions of the two sample types were explored.
Solution-doped metal powder pellets as well as aspirated liquids were used as calibration samples to analyze pure copper and zinc certified reference materials (CRMs) by femtosecond laser ablation ICP-MS. It was demonstrated that calibration by copper pellets resulted in relative deviations up to 20%, whereas fs-LA-ICP-MS among copper-based CRMs led to inaccuracies in the same range unless nominal mass fractions were chosen to be <3 mg/kg. Calibration by zinc pellets generally provided better accuracy. Depending on the analyte considered, deviations below 10% were obtained even for mass fractions close to the limit of quantification. Our data, therefore, indicate solution-doped metal powder pellets to be suitable as calibration samples for fs-LA-ICP-MS of metals. Furthermore, the utilization of liquid standards for calibration was found to result in stronger deviations of up to 50% for both copper and zinc samples which, in addition, turned out to be dependent on the plasma conditions.
Quantification of sulphur in copper metals by isotope dilution LA-ICP-MS using polyethylene frits
(2018)
Sulphur is one of the relevant impurities in copper and its alloys affecting their material properties. To ensure the quality of copper products, fast direct solid sampling techniques are very attractive. However, for the calibration suitable matrix reference materials are required. For the certification of such reference materials appropriate, SI-traceable analytical methods are essential. Therefore, a procedure was developed to quantify total sulphur in copper by combining the classical isotope dilution (ID) technique and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS).
Here, for the first time, polyethylene (PE) frits were used to prepare appropriate solid samples for the sulphur quantification in copper metals (alloyed/unalloyed) by isotope dilution LA-ICP-MS. The properties of the PE frit meet the requirements as porous material with high absorption efficiency, thermal and chemical resistance as well as low sulphur blank. Different copper reference materials were used to develop and validate the procedure. The copper samples were spiked with 34S, digested with nitric acid and then the digests were absorbed on PE frits. After drying, the frits were analysed by LA-ICP-IDMS using a Nd:YAG laser at 213 nm coupled to an ICP sector field mass spectrometer. It could be demonstrated, that the sample solution dispersed on the frits did not influence the 32S/34S ratio significantly even though the sulphur intensities were fluctuating along the scanned lines. Relative standard deviations of the isotope ratios were below 5 % in average between three line scans (except for the pure spike solution and procedure blank). The measurement results were validated by comparing them with the results obtained by conventional ICP-IDMS after analyte-matrix separation. Plotting the mass fraction of sulphur in copper obtained by LA-ICP-IDMS versus those obtained by ICP-IDMS yields a linear curve with a correlation coefficient of 0.9999 showing a strong agreement between both techniques.
The metrological traceability to the SI from the kg down to the sulphur mass fraction in copper is established by an unbroken chain of comparisons, each accompanied by an uncertainty budget. Thus, the measurement results are considered reliable, acceptable and comparable within the stated measurement uncertainty.
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is increasingly used to study the distribution of metal-containing drugs, imaging probes and nanomaterials in connection with disease related changes and therapy progress. Additionally, biomolecules can be detected indirectly by using metal-tagged antibodies.
The extracellular matrix (ECM) is, besides the cells, an important component of all body tissues. The macromolecular network of the ECM consists of structural proteins (e.g., collagen, elastin) and proteoglycans composed of highly negatively charged carbohydrates, the glycosaminoglycans (GAGs), which are covalently linked to a protein core. Many diseases, including inflammatory processes and tumors, are associated with characteristic ECM changes at an early stage. Recent studies have shown that contrast agents for magnetic resonance imaging (MRI), which are based on gadolinium containing chelate complexes or iron oxide nanoparticles, can bind themselves to ECM components.
To elucidate the role of GAGs like keratan sulfate (KS) and its modification state in disease, highly specific tools are necessary. As a complement to conventional immunohistochemistry LA-ICP-MS was applied to investigate the distribution of KS in tissue thin sections using a well characterized anti-KS antibody labelled with metal ions. Furthermore, LA-ICP-MS was used for the detection of MRI contrast agents and the identification of their target cells and molecules in tissue samples from animal models, e.g. for cardiovascular diseases. The results show the possibilities of LA-ICP-MS for the elucidation of pathological tissue changes.
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is nowadays a versatile and powerful analytical method for direct solid sample analysis. The applicability has been demonstrated for a wide variety of samples covering hard and soft materials. In an imaging mode the technique provides quantitative information on the elemental distribution within a sample. LA-ICP-MS imaging is of particular interest in biomedical research as the distribution of an element gives valuable insight on uptake and distribution of essential and toxic trace elements, administered contrast agents as well es nanoparticles. LA-ICP-MS is therefore a powerful complement to other imaging techniques. Recent instrumental improvements, especially in sample chamber design, have contributed to better sensitivity and spatial resolution enabling subcellular imaging. The book chapter provides a comprehensive overview about spatially resolved localisation and quantification of various nanoparticles in cells and tissue thin sections by LA-ICP-MS. Furthermore, different sample preparation strategies and internal standardisation and calibration approaches for bioimaging by LA-ICP-MS are summarized and discussed.
Metal-containing nanomaterials are used in numerous fields ranging from industrial applications to nanomedicine. Several studies have demonstrated that the physicochemical properties of nanoparticles have an impact on their pharmacokinetics, transfer and clearance. The high sensitivity and multielement capability of LA-ICP-MS enables the elucidation of interactions between tissue components and nanomaterials used as imaging probes or drug carriers. Potential toxic effects are investigated as well. Thus, LA imaging significantly supports the clinical translation of safe and efficient nanoparticles for diagnostic and therapeutic purposes.
The interaction of nanoparticles (NPs) with cells has become a major field of interest, ranging from medical applications to nanotoxicology. Size, shape and surface modification of the NPs determine the uptake rate and pathway into the cells, and therefore impact specific cell components and processes.
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is an established quantitative multi-elemental analysis and mapping technique. In recent years, it was shown that LA-ICP-MS can provide quantitative as well as distribution information of NPs in cell samples.
Here LA-ICP-MS was applied for the imaging of individual cells to study the uptake and intracellular processing of metal-containing nanostructures. Additionally, the local distribution of naturally occurring elements in cells like P was measured to indicate cell morphology. The cells were incubated with different types of NPs under varying experimental conditions. For LA analysis, the cells were fixed and dried.
Our findings show, that LA-ICP-MS is suitable for the localisation of nanoparticle aggregates within cellular compartments. The studied NPs accumulate in the perinuclear region in the course of intracellular processing, but do not enter the cell nucleus. The uptake efficiency depends strongly on the physicochemical properties of the nanostructures as well as on the incubation conditions like concentration and incubation time.
The results demonstrate the potential of LA-ICP-MS providing insight into NP uptake, intracellular distribution and cell-to-cell variation dependent on experimental parameters.
Nanoparticles (NPs) have found a wide range of applications in research and industry. Thereby the interaction of NPs with biological systems like cells has become a major field of interest, ranging from medical applications to nanotoxicology. Size, shape and surface modification of the nanomaterials determine the uptake rate and pathway into the cells, and therefore impact specific cell components and processes.
In recent years, elemental imaging of biological samples using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is gaining more and more importance. Improvements concerning both spatial resolution (down to 1 µm) and signal-to-background ratio due to low-dispersion LA chambers make LA-ICP-MS particularly interesting for single cell analysis.
Here LA-ICP-MS was applied for the imaging of individual cells to study the uptake and intracellular processing of metal-containing nanostructures. The cells were incubated with different NPs under varying experimental conditions and afterwards fixed with para-formaldehyde and dried for LA analysis. High-spatial resolution LA-ICP-MS was achieved by careful optimisation of the laser ablation parameters.
Our findings show, that LA-ICP-MS is applicable to localize NP aggregates within cellular compartments. The uptake efficiency depends strongly on the physicochemical properties of the nanostructures as well as on the incubation conditions like concentration and incubation time.
The results demonstrate the potential of LA-ICP-MS providing insight into nanoparticle-cell interaction dependent on experimental parameters.
Nanoparticles (NPs) have found a wide range of applications in research and industry. Thereby the interaction of NPs with biological systems like cells has become a major field of interest, ranging from medical applications to nanotoxicology. Size, shape and surface modification of the nanomaterials determine the uptake rate and pathway into the cells, and therefore impact specific cell components and processes.
Inductively coupled plasma mass spectrometry (ICP-MS) is a well-established analytical method offering high sensitivity and multi-element capability. By coupling a laser ablation (LA) system to an ICP-MS the analysis of different kinds of solid samples is possible. In recent years, it was shown that LA-ICP-MS can provide quantitative as well as distribution information of metal containing nanoparticles (NPs) in cell samples.
Here LA-ICP-MS was applied for the imaging of individual fibroblast cells to study the uptake and intracellular processing of NPs. Our results show that LA-ICP-MS can be used to localize nanoparticle aggregates within cellular compartments. The studied NPs accumulate in the perinuclear region in the course of intracellular processing, but do not enter the cell nucleus. The uptake efficiency depends strongly on the physico-chemical properties of the nanostructures as well as on the incubation conditions like concentration and incubation time.
ICP-MS was used to determine the composition of the nanomaterials as well as the number of NPs in cells after acid digestion of the samples.
In recent years, elemental imaging of biological samples like tissue thin sections using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is gaining more and more importance. Improvements concerning spatial resolution as well as signal-to-background ratio due to low-dispersion sample chambers make LA-ICP-MS also interesting for single cell analysis.
To evaluate the interaction of nanoparticles (NPs) with cells LA-ICP-MS was applied for the imaging of individual cells. Our findings show, that NP aggregates can be localized within cellular compartments. The uptake efficiency depends strongly on the physico-chemical properties of the nanostructures (size, chemical composition, surface modification), as well as on the incubation conditions (concentration, time).
Moreover, LA-ICP-MS is increasingly becoming an important complementary technique in bioanalysis by using element-tagging strategies to determine biomolecules indirectly. Based on the specific binding between antibodies and their corresponding antigens, proteins and peptides can be detected in tissue or cells using tagged antibodies. As artificial tags metal chelates loaded with lanthanides, polymer-based elemental tags or metal-containing nanoparticles can be used. Thereby LA-ICP-MS is a sensitive detection tool for multiplexed immuno-histochemistry of tissue and cell samples.
Our results demonstrate the potential of LA-ICP-MS to investigate the distribution of naturally occurring elements, administered agents as well as biomolecules by using metal-tagged antibodies.
Nanoparticles (NPs) have found a wide range of applications in research and industry. Thereby the interaction of NPs with biological systems like cells has become a major field of interest, ranging from medical applications to nanotoxicology. Size, shape and surface modification of the nanomaterials determine the uptake rate and pathway into the cells, and therefore impact specific cell components and processes.
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is an established quantitative multi-elemental analysis and mapping technique. In recent years, it was shown that LA-ICP-MS can provide quantitative as well as distribution information of metal containing nanoparticles (NPs) in cell samples.
Here LA-ICP-MS was applied for the imaging of individual fibroblast cells to study the uptake and intracellular processing of NPs. Our results show that LA-ICP-MS can be used to localize nanoparticle aggregates within cellular compartments. The studied NPs accumulate in the perinuclear region in the course of intracellular processing, but do not enter the cell nucleus. The uptake efficiency depends strongly on the physico-chemical properties of the nanostructures as well as on the incubation conditions like concentration and incubation time.
ICP-MS was used to determine the composition of the nanomaterials as well as the number of NPs in cells after acid digestion of the samples.