Quantification capabilities of N2 MICAP-MS with solution nebulization and aerosol desolvation.

The analytical capabilities of a nitrogen-sustained high-power microwave inductively coupled atmospheric-pressure plasma mass spectrometer (N2 MICAP-MS) were investigated using solution nebulization with and without aerosol desolvation. The reduced solvent load for the desolvated aerosol and the increased aerosol transfer resulted in a signal enhancement of ten times for most elements in samples without a significant amount of dissolved solids. An exception was boron, whose signal decreased by a factor of seven when a desolvator was used. To compare the accuracy, reproducibility, and matrix susceptibility of the N2 MICAP-MS, the mass fractions of 30 elements were determined in two certified water reference materials using external calibration and standard addition. The results were generally found to agree within 10% of the certified reference values with a maximum deviation of 17% in the case of 64Zn. Comparing external calibration and standard addition provided comparable results regardless of the sample introduction method. To assess the extent of matrix effects, multi-element standard solutions were doped with amounts of up to 100 mg kg-1 calcium. This resulted in a signal suppression of up to 30% and 70% for conventional nebulization and aerosol desolvation, respectively. This substantially reduced the improvement in sensitivity observed for the desolvated aerosol. To further investigate the fundamental characteristics of the N2 MICAP-MS, the plasma gas temperature was estimated using three methods. The determined temperatures for the two most reliable methods were in the range of ∼5000-6000 K and were found to be independent of the sample introduction method and similar to those of an Ar ICP.

Scallop shells as biosorbents for water remediation from heavy metals: Contributions and mechanism of shell components in the adsorption of cadmium from aqueous matrix.

To ascertain their potential for heavy metal pollution remedy, we studied the adsorption mechanism of cadmium onto scallop shells and the interactions between the heavy metal and the shell matrix. Intact shells were used to investigate the uptake and diffusion of the metal contaminant onto the shell carbonatic layers, as well as to evaluate the distribution of major and trace elements in the matrix. LA-ICPMS measurements demonstrate that Cd is adsorbed on a very thin layer on the inner and outer surfaces of the shell. Structural and thermal analyses showed the presence of 9 wt.-% of a CdCO3 phase indicating that the adsorption is mainly a superficial process which involves different processes, including ion exchange of Ca by Cd. In addition, organic components of the shell could contribute to adsorption as highlighted by different metal uptake observed for shells with different colours. In particular, darker shells appeared to adsorb more contaminant than the white ones. The contribution of the organic shell components on the adsorption of heavy metals was also highlighted by the element bulk content which showed higher concentrations of different metals in the darker specimen. Raman spectroscopy allowed to identify the pigments as carotenoids, confirmed by XRD measurements which highlighted the presence of astaxanthin phases. The results presented here provide new insights into the Cd adsorption mechanism highlighting the important contribution given by the organic components present in the biogenic carbonate matrix. Furthermore, the high efficiency of Cd removal from water by scallop shells, supported by adsorption kinetic and isotherm studies, has been demonstrated.

Results of an interlaboratory comparison for characterization of Pt nanoparticles using single-particle ICP-TOFMS.

This study describes an interlaboratory comparison (ILC) among nine (9) laboratories to evaluate and validate the standard operation procedure (SOP) for single-particle (sp) ICP-TOFMS developed within the context of the Horizon 2020 project ACEnano. The ILC was based on the characterization of two different Pt nanoparticle (NP) suspensions in terms of particle mass, particle number concentration, and isotopic composition. The two Pt NP suspensions were measured using icpTOF instruments (TOFWERK AG, Switzerland). Two Pt NP samples were characterized and mass equivalent spherical sizes (MESSs) of 40.4 ± 7 nm and 58.8 ± 8 nm were obtained, respectively. MESSs showed <16% relative standard deviation (RSD) among all participating labs and <4% RSD after exclusion of the two outliers. A good agreement was achieved between the different participating laboratories regarding particle mass, but the particle number concentration results were more scattered, with <53% RSD among all laboratories, which is consistent with results from previous ILC studies conducted using ICP-MS instrumentation equipped with a sequential mass spectrometer. Additionally, the capabilities of sp-ICP-TOFMS to determine masses on a particle basis are discussed with respect to the potential for particle density determination. Finally, because quasi-simultaneous multi-isotope and multi-element determinations are a strength of ICP-TOFMS instrumentation, the precision and trueness of isotope ratio determinations were assessed. The average of 1000 measured particles yielded a precision of below ±1% for intensity ratios of the most abundant Pt isotopes, i.e.194Pt and 195Pt, while the accuracy of isotope ratios with the lower abundant isotopes was limited by counting statistics.

Characterizing a nitrogen microwave inductively coupled atmospheric-pressure plasma ion source for element mass spectrometry.

A high-power nitrogen-based microwave inductively coupled atmospheric-pressure plasma was coupled to a quadrupole mass spectrometer to investigate its characteristics as an ion source for element mass spectrometry. The influence of operating conditions on analyte sensitivity, plasma background, and polyatomic ion formation was investigated for conventional solution-based analysis. By varying the forward power and the nebulizer gas flow rate, the plasma background ions were found to decrease with increasing gas flow rates and decreasing operating power. Analyte ions showed different trends, which could be related to the physical-chemical properties of the elements. We could identify three groups based on the location of maximum intensity in the power vs. flow rate contour plot. Atomic ions of elements with low first ionization energy and low oxygen bond strength were found to maximize at a high nebulizer gas flow rate and lower microwave power. Elements with intermediate ionization energy and higher oxygen bond strength required higher power settings for optimum sensitivity, while elements with the highest ionization energies required the highest power and lowest gas flow rates for their optimization. The latter group showed a substantial suppression in sensitivity compared to elements of similar mass, which is considered to result from the high abundance of NO in the plasma source, whose ionization energy is close to that of these elements. Metal oxide ions were found at similar or higher abundances than in the conventional argon-based ICP and could be minimized only by using a low gas flow rate and high power settings. These general trends were also observed when the vacuum interface was modified. To change the dynamics of the supersonic expansion, different sampler cone orifice sizes and sampler-skimmer distances were investigated and the interface pressure was lowered through an additional pump. These modifications did not yield significant differences in ion transmission but lowering the interface pressure reduced the relative abundance of metal oxide ions. The limits of detection were evaluated for optimized plasma conditions and found comparable to those of an argon ICP source with the same mass spectrometer.

A simple and soft chemical deaggregation method producing single-digit detonation nanodiamonds.

Detonation nanodiamonds (DNDs) are a class of very small and spherical diamond nanocrystals. They are used in polymer reinforcement materials or as drug delivery systems in the field of nanomedicine. Synthesized by detonation, only the final deaggregation step down to the single-digit nanometer size (<10 nm) unfolds their full potential. Existing deaggregation methods mainly rely on mechanical forces, such as high-power sonication or bead milling. These techniques entail drawbacks such as contamination of the sample and the need for a specialized apparatus. In this paper, we report a purely chemical deaggregation method by simply combining oxidation in air followed by a boiling acid treatment, to produce highly stable single-digit DNDs in a suspension. The resulting DNDs are surface functionalized with carboxyl groups, the final boiling acid treatment removes primary metal contaminants such as magnesium, iron or copper and the nanoparticles remain dispersed over a wide pH range. Our method can be easily carried out in a standard chemistry laboratory with commonly available laboratory apparatus. This is a key step for many DND-based applications, ranging from materials science to biological or medical applications.

LA-ICP-MS using a nitrogen plasma source.

Here we describe the first study of a nitrogen based inductively coupled plasma mass spectrometry system in conjunction with laser ablation (LA-(N2-ICP)-MS). Therefore, a microwave-sustained, inductively coupled, atmospheric-pressure plasma source was mounted onto the interface of a quadrupole ICP-MS to investigate the capabilities of such an instrument. The proof of concept study was focused on the quantification capabilities of major to trace elements. Therefore, the plasma background species under dry plasma conditions were investigated to identify the most suitable isotopes for the analysis and to describe the newly formed nitrogen plasma interferences. In addition, the instrumental drift was investigated. Selected elements in the reference materials NIST SRM 612 and BCR-2G were quantified using NIST SRM 610 as an external standard and could be determined within the uncertainty of the reference values. Finally, the limits of detection for LA-(N2-ICP)-MS and LA-(Ar-ICP)-MS were compared indicating similar or even lower LODs for most elements using LA-(N2-ICP)-MS. Therefore, a nitrogen plasma source coupled to a mass spectrometer could challenge the argon-sustained ICP-MS in element analysis by overcoming argon interferences and has the potential to reduce the plasma gas expenses significantly.

Quantification of Nanoparticles in Dispersions Using Transmission Electron Microscopy.

The quantification of the particle size and the number concentration (PNC) of nanoparticles (NPs) is key for the characterization of nanomaterials. Transmission electron microscopy (TEM) is often considered as the gold standard for assessing the size of NPs; however, the TEM sample preparation suitable for estimating the PNC based on deposited NPs is challenging. Here, we use an ultrasonic nebulizer (USN) to transfer NPs from aqueous suspensions into dried aerosols which are deposited on TEM grids in an electrostatic precipitator of an aerosol monitor. The deposition efficiency of the electrostatic precipitator was ≈2%, and the transport efficiency of the USN was ≈7%. Experiments using SiO2 NPs (50­200 nm) confirmed an even deposition of the nebulized particles in the center of the TEM grids. PNCs of the SiO2 NPs derived from TEM images underestimated the expected PNCs of the suspensions by a factor of up to three, most likely resulting from droplet coagulation and NP aggregation in the USN. Nevertheless, single particles still dominated the PNC. Our approach results in reproducible and even deposition of particles on TEM grids suitable for morphological analysis and allows an estimation of the PNC in the suspensions based on the number of particles detected by TEM.

Mass spectrometry-based approaches to study lanthanides and lanthanide-dependent proteins in the phyllosphere.

Rare-earth elements (REEs) were recently discovered to be biologically significant. The finding was originally made with the methanol dehydrogenase XoxF, which depends on REEs for its activity, and reports of lanthanide-utilizing bacteria have since expanded. Environmental proteomics allows the identification of proteins specifically induced by the presence of lanthanides or can provide insights into the preferred use of lanthanide-dependent and -independent isoenzymes, for example. Here we describe protocols for the growth and subsequent mass spectrometry-based proteome analysis of bacteria obtained from controlled artificial media and from the phyllosphere of the model plant Arabidopsis thaliana. In addition, the use of inductively coupled plasma mass spectrometry (ICP-MS) is described for the quantification of REEs in biological samples.

New Orientation: A Downward-pointing Vertical Inductively Coupled Plasma Mass Spectrometer for the Analysis of Microsamples.

We present a prototype of a vertical-downward configuration of an inductively coupled plasma mass spectrometer (ICPMS) allowing the sample introduction from the top. With this novel approach to orient the ICP downward, we aim to expand the sample transport capabilities in ICPMS especially for the transport of droplets or particles with a final goal to analyze individual cells. Because of this gravity-assisted sampling approach, the transport of larger sized droplets, that is, droplets that would be difficult to transport into a horizontally oriented ICPMS, becomes possible and, furthermore, becomes independent of the droplets' size or size distribution. We demonstrate that droplets of an initial size of 70 µm can be successfully transported into the plasma at dispensing frequencies up to 1 kHz without the need for a desolvation device. In addition, we observed that the implementation of a desolvation device, that is, a gas-exchange device (GED), can improve the detection efficiencies (DEs). Compared to operating conditions that are commonly reported for ICPMS experiments, significantly different optimization parameters (radio frequency power and gas flow rates) were tested in the presented experiments here while instrument type-specific DEs were obtained.

Untargeted metabolomics links glutathione to bacterial cell cycle progression.

Cell cycle progression requires the coordination of cell growth, chromosome replication, and division. Consequently, a functional cell cycle must be coupled with metabolism. However, direct measurements of metabolome dynamics remained scarce, in particular in bacteria. Here, we describe an untargeted metabolomics approach with synchronized Caulobacter crescentus cells to monitor the relative abundance changes of ~400 putative metabolites as a function of the cell cycle. While the majority of metabolite pools remains homeostatic, ~14% respond to cell cycle progression. In particular, sulfur metabolism is redirected during the G1-S transition, and glutathione levels periodically change over the cell cycle with a peak in late S phase. A lack of glutathione perturbs cell size by uncoupling cell growth and division through dysregulation of KefB, a K+/H+ antiporter. Overall, we here describe the impact of the C. crescentus cell cycle progression on metabolism, and in turn relate glutathione and potassium homeostasis to timely cell division.

Dual isotope system analysis of lead white in artworks.

Isotopic studies are gaining much interest in heritage science, as they can provide insight into a material's age and provenance. Radiocarbon (14C) dating affords a time frame for the materials being studied, thus providing a historical context, whereas the specific pattern of lead isotope ratios may be used to set geographical constraints on the source of the original materials. Both methods require invasive sampling from the object, and henceforth limits their respective application. With the focus on lead white paint (2PbCO3·Pb(OH)2), in this study we extract the time of production of the pigment from the carbonate anion by radiocarbon dating while its origin is traced by lead isotope analysis on the cation. The methodology was applied to 12 British and 8 Swiss paintings from the 18th to 20th century, with known dates and provenance. The 14C analysis of the lead white in combination with the organic binder and canvas alone places all objects between the 17th and 20th centuries, which is in agreement with their signed date, wheras the lead isotope analysis of all samples are consistent with lead ores from European deposits. In most of the cases the combined results are consistent with the art historical data and prove that isotope analysis is intrinsic to the object. This feasibility study conducted on paintings of known age demonstrates the possibility to maximize the information output from lead white paint, thus increasing the benefits of a single sampling.

Toward a Spatiotemporal Understanding of Dolomite Dissolution in Sandstone by CO2-Enriched Brine Circulation.

In this study, we introduce a stochastic method to delineate the mineral effective surface area (ESA) evolution during a recycling reactive flow-through transport experiment on a sandstone under geologic reservoir conditions, with a focus on the dissolution of its dolomite cement, Ca1.05Mg0.75Fe0.2(CO3)2. CO2-enriched brine was circulated through this sandstone specimen for 137 cycles (∼270 h) to examine the evolution of in situ hydraulic properties and CO2-enriched brine-dolomite geochemical reactions. The bulk permeability of the sandstone specimen decreased from 356 mD before the reaction to 139 mD after the reaction, while porosity increased from 21.9 to 23.2% due to a solid volume loss of 0.25 mL. Chemical analyses on experimental effluents during the first cycle yielded a dolomite reactivity of ∼2.45 mmol m-3 s-1, a corresponding sample-averaged ESA of ∼8.86 × 10-4 m2/g, and an ESA coefficient of 1.36 × 10-2, indicating limited participation of the physically exposed mineral surface area. As the dissolution reaction progressed, the ESA is observed to first increase and then decrease. This change in ESA can be qualitatively reproduced employing scanning electron microscopy-image-based stochastic analyses on dolomite dissolution. These results provide a new approach to analyze and upscale the ESA during geochemical reactions, which are involved in a wide range of geoengineering operations.

Cadmium accumulation and allocation in different cacao cultivars.

Cadmium (Cd) is a biologically non-essential heavy metal that can cause toxic effects in plants, animals and humans already at low concentrations compared to other metals. After Cd concentrations in cacao beans of various provenances, particularly from Latin America, were found to exceed the new regulations enforced by the European Union in 2019, there is an urgent need to find measures to lower Cd accumulation in cacao beans to acceptable values. In this research, the long-term cacao cultivar trial CEDEC-JAS in northern Honduras was used to investigate differences between 11 cultivars in Cd uptake and translocation. Sampling of various plant parts, including rootstocks, scions, leaves and beans, from three replicate trees per cultivar and the soil around each tree was conducted at this site. Results indicate that concentrations of available soil Cd were more closely correlated with Cd concentrations of the rootstocks (R2 = 0.56), scions (R2 = 0.59) and leaves (R2 = 0.46) than with bean Cd concentrations (R2 = 0.26). In addition, Cd concentrations of rootstocks, scions and leaves showed close relationships to available soil Cd concentrations, with no significant differences between the cultivars. In contrast, bean Cd concentrations showed only weak correlations to available soil Cd and Cd concentrations in the vegetative plant parts, but significant variation among cultivars. Three cultivars, which were analysed in more detail, showed significant differences in Cd concentrations of mature beans, but not of immature beans. These results suggest that cultivar-related differences in bean Cd concentrations primarily result from differences in Cd loading during bean maturation, possibly due to cultivar-specific differences in the xylem-to-phloem transfer of Cd. The results show that selection of cultivars with low Cd transfer from vegetative parts into the beans has high potential to keep Cd accumulation in cacao beans at levels that are safe for consumption.

Use of rare-earth elements in the phyllosphere colonizer Methylobacterium extorquens PA1.

Until recently, rare-earth elements (REEs) had been thought to be biologically inactive. This view changed with the discovery of the methanol dehydrogenase XoxF that strictly relies on REEs for its activity. Some methylotrophs only contain xoxF, while others, including the model phyllosphere colonizer Methylobacterium extorquens PA1, harbor this gene in addition to mxaFI encoding a Ca2+ -dependent enzyme. Here we found that REEs induce the expression of xoxF in M. extorquens PA1, while repressing mxaFI, suggesting that XoxF is the preferred methanol dehydrogenase in the presence of sufficient amounts of REE. Using reporter assays and a suppressor screen, we found that lanthanum (La3+ ) is sensed both in a XoxF-dependent and independent manner. Furthermore, we investigated the role of REEs during Arabidopsis thaliana colonization. Element analysis of the phyllosphere revealed the presence of several REEs at concentrations up to 10 µg per g dry weight. Complementary proteome analyses of M. extorquens PA1 identified XoxF as a top induced protein in planta and a core set of La3+ -regulated proteins under defined artificial media conditions. Among these was a REE-binding protein that is encoded next to a gene for a TonB-dependent transporter. The latter was essential for REE-dependent growth on methanol indicating chelator-assisted uptake of REEs.

Skip the beat: minimizing aliasing error in LA-ICP-MS measurements.

Pulsed laser ablation sampling and sequential isotope detection can lead to signal beat in the registered signal intensities. In particular, if aerosol transport systems deliver ablated aerosol with temporal duration close to that of a single mass scan, such signal beat can become significant and lead to biased intensity ratios and concentrations. Averaging signal intensities based on the least common multiple of scan duration and laser pulse period can eliminate such a systematic bias and improve the accuracy of quantitative laser ablation experiments. The method was investigated for experiments using an ablation cell that provided aerosol washout times near 200 ms and quadrupole-based ICP-MS acquisition using different dwell and settling times that were compared with and extended by numerical simulations. It was found that the systematic bias of acquired data could exceed the inherent noise of laser ablation inductively couple plasma mass spectrometry experiments and that the averaging method could successfully minimize the bias due to beating. However, simulations revealed that this was only the case for combinations of pulse frequency and scan duration in which the number of laser pulses within the averaged period was an integer multiple of the number of isotopes in the acquisition method. In element imaging applications, this averaging will necessarily increase the size of individual pixels and it depends not only on the laser beam size but also pulse repetition rate and the acquisition settings for a sequential mass spectrometer. Graphical abstract LCM averaging can prevent occurrence of a systematic bias in LA-ICPMS measurements.

Peptide-Coated Platinum Nanoparticles with Selective Toxicity against Liver Cancer Cells.

Peptide-stabilized platinum nanoparticles (PtNPs) were developed that have significantly greater toxicity against hepatic cancer cells (HepG2) than against other cancer cells and non-cancerous liver cells. The peptide H-Lys-Pro-Gly-dLys-NH2 was identified by a combinatorial screening and further optimized to enable the formation of water-soluble, monodisperse PtNPs with average diameters of 2.5 nm that are stable for years. In comparison to cisplatin, the peptide-coated PtNPs are not only more toxic against hepatic cancer cells but have a significantly higher tumor cell selectivity. Cell viability and uptake studies revealed that high cellular uptake and an oxidative environment are key for the selective cytotoxicity of the peptide-coated PtNPs.

Replacing the Argon ICP: Nitrogen Microwave Inductively Coupled Atmospheric-Pressure Plasma (MICAP) for Mass Spectrometry.

We combine a recently developed high-power, nitrogen-sustained microwave plasma source-the Microwave Inductively Coupled Atmospheric-Pressure Plasma (MICAP)-with time-of-flight mass spectrometry (TOFMS) and provide the first characterization of this elemental mass spectrometry configuration. Motivations for assessment of this ionization source are scientific and budgetary: unlike the argon-sustained Inductively Coupled Plasma (ICP), the MICAP is sustained with nitrogen, which eliminates high operating costs associated with argon-gas consumption. Additionally, use of a commercial grade magnetron for microwave generation simplifies plasma-powering electronics. In this study, we directly compare MICAP-TOFMS performance with that of an argon-ICP as the atomic ionization source on the same TOFMS instrument. Initial results with the MICAP source demonstrate limits of detection and sensitivities that are, for most elements, on par with those of the ICP-TOFMS. The N2-MICAP source provides a much "cleaner" background spectrum than the ICP; absence of argon-based interferences greatly simplifies analysis of isotopes such as 40Ca, 56Fe, and 75As, which typically suffer from spectral interferences in ICP-MS. The major plasma species measured from the N2-MICAP source include NO+, N2+, N+, N3+, O2+, N4+, and H2O+; we observed no plasma-background species above mass-to-charge 60. Absence of troublesome argon-based spectral interferences is a compelling advantage of the MICAP source. For example, with MICAP-TOFMS, the limit of detection for arsenic is less than 100 ng L-1 even in a 1% NaCl solution; with ICP-MS, 35Cl40Ar+ interferes with 75As+ and arsenic analysis is difficult-to-impossible in chlorine-containing matrices.

Bismesitoylphosphinic Acid (BAPO-OH): A Ligand for Copper Complexes and Four-Electron Photoreductant for the Preparation of Copper Nanomaterials.

Bismesitoylphosphinic acid, (HO)PO(COMes)2 (BAPO-OH), is an efficient photoinitiator for free-radical polymerizations of olefins in aqueous phase. Described here are the structures of various copper(II) and copper(I) complexes with BAPO-OH as the ligand. The complex CuII (BAPO-O)2 (H2 O)2 is photoactive, and under irradiation with UV light in aqueous phase, it serves as a source of metallic copper in high purity and yield (>80 %). Simultaneously, the radical polymerization of acrylates can be initiated and allows the preparation of nanoparticle/polymer nanocomposites in which the metallic Cu nanoparticles are protected against oxidation. The determination of the stoichiometry of the photoreductions suggests an almost quantitative conversion from CuII into Cu0 with half an equivalent of BAPO-OH, which serves as a four-electron photoreductant.

Highly-sensitive open-cell LA-ICPMS approaches for the quantification of rare earth elements in natural carbonates at parts-per-billion levels.

This work presents a high-sensitivity approach to quantify ultra-trace concentrations of rare earth elements (REEs) in speleothem carbonates using open-cell laser ablation-sector field-inductively coupled plasma mass spectrometry (open-cell LA-SF-ICPMS). Specifically, open-cell LA in combination with a gas exchange device enabled sampling of large-scale carbonate specimens in an ambient environment. The use of a "jet" vacuum interface and the addition of small amounts of N2 gas allowed for a 20-40 fold sensitivity enhancement compared to the conventional interface configuration. Mass load effects, quantification capabilities and detection power were investigated in analyses of reference materials using various combinations of spot sizes and laser repetition rates. From a 160 µm diameter circular laser spot and 10 Hz ablation frequency, limits of detection were in the low or sub-ng g-1 range for REEs. Little dependence of Ca normalized sensitivity factors on the amount of material introduced into the plasma was observed. Relative deviations of quantified concentrations from USGS MACS-3 preferred values were smaller than 12%. The analytical approach enabled the determination of REE concentration profiles at the single digit ng g-1 level. Application to a 15-cm piece stalagmite collected from East Timor revealed at least two abrupt elevations in light rare earth elements (LREEs) within a scanning distance of 8 mm. These anomaly regions extended over a distance of ≈200 µm and showed LREE abundances elevated by at least one order of magnitude. This high-resolution open-cell LA-SF-ICPMS method has the potential to be applied in micro-domain analyses of other natural carbonates, such as travertine, tufa, and flowstones. This is promising for a better understanding of earth and environmental sciences.

Laser Ablation - Accelerator Mass Spectrometry: An Approach for Rapid Radiocarbon Analyses of Carbonate Archives at High Spatial Resolution.

A new instrumental setup, combining laser ablation (LA) with accelerator mass spectrometry (AMS), has been investigated for the online radiocarbon ((14)C) analysis of carbonate records. Samples were placed in an in-house designed LA-cell, and CO2 gas was produced by ablation using a 193 nm ArF excimer laser. The (14)C/(12)C abundance ratio of the gas was then analyzed by gas ion source AMS. This configuration allows flexible and time-resolved acquisition of (14)C profiles in contrast to conventional measurements, where only the bulk composition of discrete samples can be obtained. Three different measurement modes, i.e. discrete layer analysis, survey scans, and precision scans, were investigated and compared using a stalagmite sample and, subsequently, applied to terrestrial and marine carbonates. Depending on the measurement mode, a precision of typically 1-5% combined with a spatial resolution of 100 µm can be obtained. Prominent (14)C features, such as the atomic bomb (14)C peak, can be resolved by scanning several cm of a sample within 1 h. Stalagmite, deep-sea coral, and mollusk shell samples yielded comparable signal intensities, which again were comparable to those of conventional gas measurements. The novel LA-AMS setup allowed rapid scans on a variety of sample materials with high spatial resolution.