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Innate immune systems alter the concentrations of trace elements in host niches in response to invading pathogens during infection. This work reports the interplay between d-block metal ions and their associated biomolecules using hyphenated elemental techniques to spatially quantify both elemental distributions and the abundance of specific transport proteins. Here, lung tissues were collected for analyses from naïve and Streptococcus pneumoniae-infected mice fed on a zinc-restricted or zinc-supplemented diet. Spatiotemporal distributions of manganese (55Mn), iron (56Fe), copper (63Cu), and zinc (66Zn) were determined by quantitative laser ablation–inductively coupled plasma–mass spectrometry. The murine transport proteins ZIP8 and ZIP14, which are associated with zinc transport, were also imaged by incorporation of immunohistochemistry techniques into the analytical workflow. Collectively, this work demonstrates the potential of a single instrumental platform suitable for multiplex analyses of tissues and labelled antibodies to investigate complex elemental interactions at the host-pathogen interface. Further, these methods have the potential for broad application to investigations of biological pathways where concomitant measurement of elements and biomolecules is crucial to understand the basis of disease and aid in development of new therapeutic approaches. [ABSTRACT FROM AUTHOR]

While quadrupoles provide unit mass resolution across the entire mass range, alternative analysers, (sector field and time-of-flight) were developed to increase mass resolution and to improve selectivity for interfered analytes. Increasing mass resolution is inherent with a loss in ion transmission and therefore, sensitivity is sacrificed in a trade-off for selectivity. In inductively coupled plasma-mass spectrometry (ICP-MS), the analysis of some elements may benefit from this increased selectivity, but many elements are not interfered, and their trace analysis would rather benefit from increased sensitivity. Performing low resolution ICP-MS can be achieved in the bandpass mode, in which scanning properties of the quadrupole are altered to boost ion transmission. The aim is to gain sensitivity at the expense of mass resolution and therefore selectivity. Here, unit mass resolution is deliberately given up to trigger two main effects: first, an increased bandwidth improves ion transmission for each isotope. Second, isotopic signals start to convolute and can be analysed at one point. This enables the simultaneous transmission and acquisition of isotopes from polyisotopic elements increasing sensitivity substantially. Both effects are cumulative and can enhance limits of analysis as long as potential interferences are considered and avoided. This perspective details technicalities, the potential, and pitfalls of the bandpass mode for ICP-MS. Applications and future potential are discussed for different hyphenated techniques and modes, namely LC-ICP-MS, LA-ICP-MS and SP ICP-MS. Distinct effects and strategies in the bandpass mode are detailed and provide options to develop dedicated methods tailored for certain elements, samples, and scientific questions. However, the loss of selectivity is inherent with a longer list of potential interferences, which is discussed for specific examples. [ABSTRACT FROM AUTHOR]

Fluorine (F) plays an important role in biology and geology but is hard to analyse and quantify using element-specific techniques. This is related to its high first ionisation potential and analytical methods depending on high energy sources for excitation and/or ionisation of F. In particular ICP-MS was initially found incapable of detecting F; however, recent methodological advances, i.e., the application of Ba as a plasma modifier and the application of tandem mass spectrometry, enabled its analysis by targeting BaF+. In this study, we suggest this approach in conjunction with laser ablation to perform the mapping of F in both biological and geological samples. In a proof of concept, tooth samples as biological samples and a Rhynie chert as a geological sample were analysed. For method development and to evaluate the performance of the developed method, gelatine-based F-standards were prepared and characterised using combustion ion chromatography. Standards were further interrogated to estimate LODs and LOQs. Depending on the required spatial resolution, figures of merit in the upper ng g−1 range and lower μg g−1 range were achievable. This is the first example of F mapping using LA-ICP-MS instrumentation and the developed methods close an important analytical gap by enabling the spatially resolved F analysis at relevant biological and geological concentrations. [ABSTRACT FROM AUTHOR]

Inductively coupled–plasma mass spectrometry (ICP-MS) has transformed our knowledge on the role of trace and major elements in biology and has emerged as the most versatile technique in elemental mass spectrometry. The scope of ICP-MS has dramatically changed since its inception, and nowadays, it is a mature platform technology that is compatible with chromatographic and laser ablation (LA) systems. Over the last decades, it kept pace with various technological advances and was inspired by interdisciplinary approaches which endorsed new areas of applications. While the first part of this review was dedicated to fundamentals in ICP-MS, its hyphenated techniques and the application in biomonitoring, isotope ratio analysis, elemental speciation analysis, and elemental bioimaging, this second part will introduce relatively current directions in ICP-MS and their potential to provide novel perspectives in the medical sciences. In this context, current directions for the characterisation of novel nanomaterials which are considered for biomedical applications like drug delivery and imaging platforms will be discussed while considering different facets of ICP-MS including single event analysis and dedicated hyphenated techniques. Subsequently, immunochemistry techniques will be reviewed in their capability to expand the scope of ICP-MS enabling analysis of a large range of biomolecules alongside elements. These methods inspired mass cytometry and imaging mass cytometry and have the potential to transform diagnostics and treatment by offering new paradigms for personalised medicine. Finally, the interlacing of immunochemistry methods, single event analysis, and functional nanomaterials has opened new horizons to design novel bioassays which promise potential as assets for clinical applications and larger screening programs and will be discussed in their capabilities to detect low-level proteins and nucleic acids. [ABSTRACT FROM AUTHOR]

Since its inception in the early 80s, inductively coupled plasma–mass spectrometry has developed to the method of choice for the analysis of elements in complex biological systems. High sensitivity paired with isotopic selectivity and a vast dynamic range endorsed ICP-MS for the inquiry of metals in the context of biomedical questions. In a stand-alone configuration, it has optimal qualities for the biomonitoring of major, trace and toxicologically relevant elements and may further be employed for the characterisation of disrupted metabolic pathways in the context of diverse pathologies. The on-line coupling to laser ablation (LA) and chromatography expanded the scope and application range of ICP-MS and set benchmarks for accurate and quantitative speciation analysis and element bioimaging. Furthermore, isotopic analysis provided new avenues to reveal an altered metabolism, for the application of tracers and for calibration approaches. In the last two decades, the scope of ICP-MS was further expanded and inspired by the introduction of new instrumentation and methodologies including novel and improved hardware as well as immunochemical methods. These additions caused a paradigm shift for the biomedical application of ICP-MS and its impact in the medical sciences and enabled the analysis of individual cells, their microenvironment, nanomaterials considered for medical applications, analysis of biomolecules and the design of novel bioassays. These new facets are gradually recognised in the medical communities and several clinical trials are underway. Altogether, ICP-MS emerged as an extremely versatile technique with a vast potential to provide novel insights and complementary perspectives and to push the limits in the medical disciplines. This review will introduce the different facets of ICP-MS and will be divided into two parts. The first part will cover instrumental basics, technological advances, and fundamental considerations as well as traditional and current applications of ICP-MS and its hyphenated techniques in the context of biomonitoring, bioimaging and elemental speciation. The second part will build on this fundament and describe more recent directions with an emphasis on nanomedicine, immunochemistry, mass cytometry and novel bioassays. [ABSTRACT FROM AUTHOR]

This work introduces novel and universal workflows for the analysis of intact proteins by capillary electrophoresis and presents guidelines for the targeted selection of appropriate background electrolytes (BGEs) by consideration of the target proteins' isoelectric point (pI). The suitability of neutral dimethyl polysiloxane (PDMS) capillaries with dynamic coatings of cationic cetyltrimethylammonium bromide (CTAB) or anionic sodium dodecyl sulfate (SDS), and bare fused silica (BFS) capillaries were systematically evaluated for the analysis of histidine and seven model proteins in six BGEs with pH values between 3.0 and 9.6. Multiple capillary and BGE combinations were suitable for the analysis of all proteins with molecular weights ranging from 13.7–150 kDa, and pIs between 4.7 and 9.6. The CTAB-PDMS capillary was best suited for low pH BGEs, while the SDS-PDMS and BFS capillary were superior for high pH BGEs. These combinations consistently resulted in sharp peak shapes and rapid migration times. pH values of BGEs closer to the proteins' pI produced poorer peak shapes and decreased effective mobilities due to suppressed ionisation. Plots of mobility vs. pH crossed at approximately the pI of the protein in most cases. The workflow was applied to the analysis of caseins and whey proteins in milk for the separation of the seven most abundant proteins, including the isoforms of A1 and A2 β-casein and β-lactoglobulin A and B. [ABSTRACT FROM AUTHOR]

This work introduces a new method for immuno-mass spectrometry imaging via quadrupole-based laser ablation-inductively coupled plasma-mass spectrometry instruments that is matched to the abundance of elements in biological tissues. Manipulation of ion-optics and quadrupole mass filter parameters provided increased transmission of low level high-mass elements, which are typically used as labels for antibodies, at the expense of highly abundant endogenous low-mass elements. Transmission of mid-mass elements such as transition metals was only slightly affected. The implications for mass resolution and background signals are critically discussed and signal to noise ratios and imaging capabilities are compared to those obtained from a standard method. This novel approach resulted in a 6-fold improved signal to noise ratio for lanthanides that are routinely used as elemental labels for antibodies to target protein distributions in biological tissues. This increase in signal intensity, enhanced contrasts, lower limits of detection and the potential to improve spatial resolution contributed to enhanced imaging and trace analyses, as demonstrated by imaging murine brain sections of the hippocampal system and substantia nigra. [ABSTRACT FROM AUTHOR]

This study presents a novel size exclusion chromatography-inductively coupled plasma-mass spectrometry (SEC-ICP-MS) method for the characterisation and quantification of immunoassays with lanthanide-labelled antibodies. SEC-ICP-MS in combination with a double isotope dilution approach enabled facile validation of the antibodies' integrity, the determination of the batch to batch labelling efficiency, monitoring of each labelling step, and quantification of the immunocomplexes after incubation with the target protein. The addition of oxygen into the dynamic reaction cell improved the detection of sulphur as a marker for the antibodies and target protein via mass-shifting (LOD = 3.7 ng/mL), whilst maintaining sufficient sensitivity for the analysis of the lanthanides. Ultra-high performance liquid chromatography (UHPLC) SEC ensured a rapid chromatographic method with separation times under 7 min of the labelled and unlabelled antibodies, the immunocomplexes, and the unconjugated polymer used to lanthanide-label the antibodies. SEC calibration estimated the molecular weights of all peaks and provided valuable insights in immunochemical reactions and the stoichiometry of the reactants and products. A novel on-line isotope dilution analysis (IDA) enabled absolute quantification of sulphur and lanthanide signals and the protein of interest. The chromatographic separation of immunocomplexes and labelled antibodies allowed the simultaneous determination of the antibody/metal stoichiometry and target protein concentration from a single mass flow chromatogram. An immunoglobulin protein was quantified after incubation with an 153Eu-labelled primary polyclonal antibody. The procedure was validated with direct labelling of the target protein with 156Gd for parallel, simultaneous quantification. The concentration determined via direct labelling of the protein deviated 1.9% from the immunochemical approach employing 153Eu-labelled polyclonal antibodies. [ABSTRACT FROM AUTHOR]

We present a novel on-line isotope dilution analysis (IDA) approach for the quantification of isotopically enriched metal labels used in immunohistochemical assisted imaging mass spectrometry. This technique advances recently reported on-line IDA for laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) by performing on-line reverse IDA of isotopically enriched elements commonly used as labels for antibodies. This approach allows relative quantification of biomolecules and is superior to other methods that have long acquisition times such as three-dimensional LA-ICP-MS, or when higher sample throughput is required. As a proof of concept, anti-tyrosine hydroxylase was labelled with Yb isotopes and incubated on two parallel cryocut sections of a mouse brain. IDA dependent parameters were determined by ablation of matrix-matched standards. Quantification by IDA was compared against external calibration and was a more robust method, unaffected by sensitivity changes originating from plasma drifts or spontaneous plasma fluctuations. [ABSTRACT FROM AUTHOR]

MMP-11 is a member of the matrix metalloproteinase family (MMPs) which are overexpressed in cancer cells, stromal cells and the adjacent microenvironment. The MMP protein family encompasses zinc-dependent endopeptidases that degrade the extracellular matrix (ECM), facilitating the breakdown of the basal membrane and matrix connective tissues. This function is believed to be important in cancer development and metastasis. This paper investigated a gold nanoparticle-based immunohistochemical assay to visualise the distribution of MMP-11 in human breast cancer tissues from eight patients with and without metastases by employing laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The expression of MMP-11 was increased and more heterogeneous in metastatic specimens compared to non-metastatic tumour samples. These findings demonstrate that imaging breast tumours by LA-ICP-MS may be a useful tool to aid the prognosis and treatment of breast cancer. As an example, samples of two patients are presented who were diagnosed with matching characteristics and grades of breast cancer. Although both patients had a similar prognosis and treatment, only one developed metastases. [ABSTRACT FROM AUTHOR]

Technetium (Tc) and Gadolinium (Gd) are the two most widely used metals in diagnostic medicine for scintigraphies and magnet resonance imaging (MRI), respectively. They play a crucial role for the generation or enhancement of contrast and are indispensable in countless diagnostic applications. However, the use of such contrast agents has caused severe health issues and environmental anomalies. This review aims to point out current issues and developments regarding the role and the analysis of these trace metals in medicine and the environment. Basic principles, issues and state of art of analytical methodologies are summarized. Current and future trends and the suggested implementation of novel methodologies and instrumentation are presented. [ABSTRACT FROM AUTHOR]

Elemental bio-imaging (EBI) of trace metal distributions in tissue sections is typically performed by laser ablation-single quadrupole-inductively coupled plasma-mass spectrometry (LA-ICP-SQ-MS) in which the sensitivity of biologically relevant elements such as Fe may be inhibited by polyatomic interferences. The triple quadrupole ICP-MS (ICP-QQQ-MS) is designed to reduce interferences and was examined for its potential application to EBI. Three tune modes; a no-gas, an H2, and an O2/H2 tune were developed and investigated for their suitability. All three performed well with high signal to noise ratios and low limits of detection. The O2/H2 tune was applied to a prostate cancer biopsy sample, with high levels of Zn found in the area correlating with the cancer. The oxygen mass shift was applied to image P and Se in a mouse brain. The unique focussing properties of the ICP-QQQ-MS and the ability to use mixed cell gases provided sensitive analyses of all measured isotopes with the O2/H2 tune, including those unaffected by mass shift reactions. [ABSTRACT FROM AUTHOR]

To sensitively determine 99Tc, a new method for internal quantification of its most common and stable species, [99Tc]Tc O 4 - , was developed. Anion-exchange chromatography (IC) was coupled to inductively coupled plasma–mass spectrometry (ICP-MS) and equipped with an aerosol desolvation system to provide enhanced detection power. Due to a lack of commercial Tc standards, an isotope dilution-like approach using a Ru spike and called isobaric dilution analysis (IBDA) was used for internal quantification of 99Tc. This approach required knowledge of the sensitivities of 99Ru and 99Tc in ICP-MS. The latter was determined using an in-house prepared standard manufactured from decayed medical 99mTc-generator eluates. This standard was cleaned and preconcentrated using extraction chromatography with TEVA resin and quantified via total reflection X-ray fluorescence (TXRF) analysis. IC coupled to ICP-MS enabled to separate, detect and quantify [99Tc]Tc O 4 - as most stable Tc species in complex environments, which was demonstrated in a proof of concept. We quantified this species in untreated and undiluted raw urine collected from a patient, who previously underwent scintigraphy with a 99mTc-tracer, and determined a concentration of 19.6 ± 0.5 ng L−1. The developed method has a high utility to characterize a range of Tc-based radiopharmaceuticals, to determine concentrations, purity, and degradation products in complex samples without the need to assess activity parameters of 99(m)Tc. [ABSTRACT FROM AUTHOR]

This work demonstrates the first forensic application of GC-ICP-MS for improved investigations of volatile organic compounds originating from a decomposing body. Volatile organic compounds were extracted from the headspace of human remains using sorbent tubes over a total time of 39 days. To account for naturally abundant species, control sites were prepared and sampled accordingly. All samples were spiked with an internal standard to minimise drift effects and errors during sample preparation and further analysis. Compound independent quantification was possible from a single chromatogram with a standard mix containing volatile pesticide compounds representing different mass fractions of target elements for calibration. Phosphorus, sulphur and chlorine were investigated as biologically relevant elements, which potentially form detectable volatile species during decomposition. The limits of detection of these elements in the headspace were 0.7, 5.4 and 1.6 ng/L, respectively. For sulphur, we identified abundant species which increased in concentrations of up to 1310 ng/L in the headspace above the remains. The concentrations were time dependent and show potential as forensic markers to determine post-mortem intervals or decomposition states. The universal quantification, standardisation and the high sensitivity of GC-ICP-MS augments traditional GC-MS analyses. Image 1 • First forensic application of GC-ICP-MS for quantitative speciation of VOCs. • Compound independent quantification of S-, P- and Cl-species at trace levels. • Various volatile S compounds were detectable at specific decomposition states. • Accurate quantification of S-species allows to estimate the post-mortem interval. [ABSTRACT FROM AUTHOR]

Background: Elements are the basis of life on Earth, whereby organisms are essentially evolved chemical substances that dynamically interact with each other and their environment. Determining species elemental quotas (their elementome) is a key indicator for their success across environments with different resource availabilities. Elementomes remain undescribed for functionally diverse dinoflagellates within the family Symbiodiniaceae that includes coral endosymbionts. We used dry combustion and ICP-MS to assess whether Symbiodiniaceae (ten isolates spanning five genera Breviolum, Cladocopium, Durusdinium, Effrenium, Symbiodinium) maintained under long-term nutrient replete conditions have unique elementomes (six key macronutrients and nine micronutrients) that would reflect evolutionarily conserved preferential elemental acquisition. For three isolates we assessed how elevated temperature impacted their elementomes. Further, we tested whether Symbiodiniaceae conform to common stoichiometric hypotheses (e.g., the growth rate hypothesis) documented in other marine algae. This study considers whether Symbiodiniaceae isolates possess unique elementomes reflective of their natural ecologies, evolutionary histories, and resistance to environmental change. Results: Symbiodiniaceae isolates maintained under long-term luxury uptake conditions, all exhibited highly divergent elementomes from one another, driven primarily by differential content of micronutrients. All N:P and C:P ratios were below the Redfield ratio values, whereas C:N was close to the Redfield value. Elevated temperature resulted in a more homogenised elementome across isolates. The Family-level elementome was (C19.8N2.6 P1.0S18.8K0.7Ca0.1) · 1000 (Fe55.7Mn5.6Sr2.3Zn0.8Ni0.5Se0.3Cu0.2Mo0.1V0.04) mmol Phosphorous-1 versus (C25.4N3.1P1.0S23.1K0.9Ca0.4) · 1000 (Fe66.7Mn6.3Sr7.2Zn0.8Ni0.4Se0.2Cu0.2Mo0.2V0.05) mmol Phosphorous -1 at 27.4 ± 0.4 °C and 30.7 ± 0.01 °C, respectively. Symbiodiniaceae isolates tested here conformed to some, but not all, stoichiometric principles. Conclusions: Elementomes for Symbiodiniaceae diverge from those reported for other marine algae, primarily via lower C:N:P and different micronutrient expressions. Long-term maintenance of Symbiodiniaceae isolates in culture under common nutrient replete conditions suggests isolates have evolutionary conserved preferential uptake for certain elements that allows these unique elementomes to be identified. Micronutrient content (normalised to phosphorous) commonly increased in the Symbiodiniaceae isolates in response to elevated temperature, potentially indicating a common elemental signature to warming. [ABSTRACT FROM AUTHOR]

Single particle (SP) and single cell (SC) inductively coupled plasma-mass spectrometry (ICP-MS) are gaining increasing momentum in environmental and medical sciences for the analysis of nanoparticles, microstructures, and individual cells. This work presents an open-source Python-based SP/SC ICP-MS data processing platform with an interactive graphical user interface. The program guides users through the analysis of large data sets and uses efficient and transparent algorithms. Gaussian and Poisson-based data filtering enables fit for purpose thresholding of particle signals from background noise. Implementation of windowed filters extends applicability of the software to SP laser ablation-ICP-MS and other data sets that contain drifting or variable backgrounds. SP or SC signals recorded with multiple data points are integrated and several distinct calibration and processing pathways may be used to determine masses, sizes, and number concentrations, or to calculate intracellular concentrations. Relevant parameters including means, medians, ionic background levels and limits of analysis are automatically calculated and visualised together with histograms of raw and calibrated data. As a proof of principle, the developed data processing platform was employed to characterise TiO2 nanoparticles in surface water, microplastic particles in soil and the C content across individual cells. [ABSTRACT FROM AUTHOR]

Nanoparticles (NPs) can be found throughout our direct environment as well as in a large range of consumer products. However, there is a lack of data on abundances and properties, which requires dedicated methods to identify and characterise NP entities. Single particle inductively coupled plasma-mass spectrometry (SP ICP-MS) is becoming one of the most relevant methods for counting NPs and studying NP composition and properties. Especially time-of-flight (TOF) technology for ICP-MS holds the key to study single particle composition and to perform non-target particle screening. This is achieved through the unique detection paradigm in TOF acquiring all isotopes across the periodic table at 35 kHz and faster. Nevertheless, non-targeted screening methods face limitations due to two factors. First, large data sets challenge data processing units and require substantial time, and second, for each isotope/element, a decision limit to distinguish between random noise and a SP signal has to be established. Here, we propose a novel lognormal approximation method to rapidly model background levels and decision limits. This method was integrated in a pre-analysis tool which detected SP data signatures of all m/z recorded via SP ICP-TOF-MS. Within seconds, particulate elements could be pinpointed in large data files and selected for more dedicated characterisation steps. In a proof of concept, we used this non-target screening method to identify inorganic NPs in selected samples of whisky, vodka, gin, and liqueur. Following qualitative analyses, number concentrations, compositions, masses, and size distributions were investigated. Besides Mn, Fe and Cu as expected NP entities, Ti, Ag, Au and Sn-based particles were found in investigated samples. [ABSTRACT FROM AUTHOR]

Its easy accessibility, ideal physical properties and the multifaceted redox chemistry made 99mTc the most important radionuclide for SPECT (single-photon emission computed tomography) in nuclear medicine. Unfortunately, small concentrations used in scintigraphy are also limiting analytical techniques to perform routine quality controls and to support the development of novel tracers. In this work, speciation analysis via liquid chromatography (LC) coupled with elemental and molecular mass spectrometry is developed for novel and established Tc radiopharmaceuticals to enable direct identification, characterization, and quantification. Here, an Orbitrap-based ESI-MS method was used to attain high mass resolutions and high mass accuracies for compound identification. RP-HPLC-ICP-MS was employed for the separation and sensitive detection of Tc species. Due to a lack of Tc standards, the previously introduced "isobaric dilution analysis" was modified and applied in an on-line post-column dilution approach. Besides the expected tracers, various Tc impurities were detected and calibrated in a non-target approach. The presented methods allow fast on-site quality controls of commercially available tracers, but further promote the characterization of novel experimental tracers in nuclear medicine without the need of "cold" reference compounds. [ABSTRACT FROM AUTHOR]

The rate of decommissioning of global oil and gas production facilities will accelerate over coming decades, as mature developments reach the end of use, and consumers transition towards renewable energy. Decommissioning strategies should include thorough environmental risk assessments which consider contaminants which are known to be present in oil and gas systems. Mercury (Hg) is a global pollutant that occurs naturally in oil and gas reservoirs. However, knowledge of Hg contamination in transmission pipelines and process equipment is limited. We investigated the potential for accumulation of Hg0 within production facilities, particularly those transporting gases, by considering the deposition of Hg onto steel surfaces from the gas phase. Following incubation experiments in a Hg saturated atmosphere; fresh API 5L‐X65 and L80–13Cr steels were found to adsorb 1.4 × 10−5 ± 0.04 × 10−5 and 1.1 × 10−5 ± 0.04 × 10−5 g m−2, respectively, while corroded samples of the same steels adsorbed 0.12 ± 0.01 and 0.83 ± 0.02 g m−2; an increase in adsorbed mercury by four orders of magnitude. The association between surface corrosion and Hg was demonstrated by laser ablation ICPMS. The levels of Hg measured on the corroded steel surfaces indicates a potential environmental risk; therefore, mercury speciation (including the presence of ß-HgS, not considered in this study), concentrations and cleaning methods should be considered when developing oil and gas decommissioning strategies. [Display omitted] • Mercury (Hg) adsorbs onto corroded steel more than onto non-corroded steel by a difference of four orders of magnitude. • Laser ablation showed mercury is co-located with corrosion on the steel surface. • In the future, leaching from pipelines may see a significant increase in oceanic Hg concentrations. [ABSTRACT FROM AUTHOR]

The biological function of minor and trace elements is ordinarily determined by their association with specific proteins, peptides and other biomolecules. Therefore, measuring the total elemental content of a biological sample provides limited information, particularly when a specific effect is due to an individual metal-protein complex. Speciation of metalloproteins, heteroatom-containing molecules or other compounds tagged with an exogenous metal can be used to overcome this limitation. A range of chromatographic separation techniques with on-line elemental detection using inductively coupled plasma-mass spectrometry (ICP-MS) have been applied to the biosciences, and each technique has intrinsic features that must be considered when designing speciation experiments. This tutorial review provides an overview of speciation in the biosciences, highlighting the unique abilities and limitations encountered. A selection of recent technical advances and new applications, the challenges of sample preparation and implementation of new technical developments are discussed, as well as the future directions of technology that is rapidly gaining a foothold in the contemporary biochemistry laboratory. [ABSTRACT FROM AUTHOR]

The analysis of natural and anthropogenic nanomaterials (NMs) in the environment is challenging and requires methods capable to identify and characterise structures on the nanoscale regarding particle number concentrations (PNCs), elemental composition, size, and mass distributions. In this study, we employed single particle inductively coupled plasma-mass spectrometry (SP ICP-MS) to investigate the occurrence of NMs in the Melbourne area (Australia) across 63 locations. Poisson statistics were used to discriminate between signals from nanoparticulate matter and ionic background. TiO2-based NMs were frequently detected and corresponding NM signals were calibated with an automated data processing platform. Additionally, a method utilising a larger mass bandpass was developed to screen for particulate high-mass elements. This procedure identified Pb-based NMs in various samples. The effects of different environmental matrices consisting of fresh, brackish, or seawater were mitigated with an aerosol dilution method reducing the introduction of salt into the plasma and avoiding signal drift. Signals from TiO2- and Pb-based NMs were counted, integrated, and subsequently calibrated to determine PNCs as well as mass and size distributions. PNCs, mean sizes, particulate masses, and ionic background levels were compared across different locations and environments. [ABSTRACT FROM AUTHOR]

Multiple sclerosis (MS) is a prevalent immune-mediated inflammatory disease of the central nervous system inducing a widespread degradation of myelin and resulting in neurological deficits. Recent advances in molecular and atomic imaging provide the means to probe the microenvironment in affected brain tissues at an unprecedented level of detail and may provide new insights. This study showcases state-of-the-art spectroscopic and mass spectrometric techniques to compare distributions of molecular and atomic entities in MS lesions and surrounding brain tissues. MS brains underwent post-mortem magnetic resonance imaging (MRI) to locate and subsequently dissect MS lesions and surrounding white matter. Digests of lesions and unaffected white matter were analysed via ICP-MS/MS revealing significant differences in concentrations of Li, Mg, P, K, Mn, V, Rb, Ag, Gd and Bi. Micro x-ray fluorescence spectroscopy (μXRF) and laser ablation – inductively coupled plasma – time of flight – mass spectrometry (LA-ICP-ToF-MS) were used as micro-analytical imaging techniques to study distributions of both endogenous and xenobiotic elements. The essential trace elements Fe, Cu and Zn were subsequently calibrated using in-house manufactured gelatine standards. Lipid distributions were studied using IR-micro spectroscopy and matrix assisted laser desorption/ionisation mass spectrometry imaging (MALDI-MSI). MALDI-MSI was complemented with high-resolution tandem mass spectrometry and trapped ion mobility spectroscopy for the annotation of specified phospho- and sphingolipids, revealing specific lipid species decreased in MS lesions compared to surrounding white matter. This explorative study demonstrated that modern molecular and atomic mapping techniques provide high-resolution imaging for relevant bio-indicative entities which may complement our current understanding of the underlying pathophysiological processes. TOC caption: State-of-the-art imaging techniques were used to investigate lesions and surrounding white matter of brain tissues from patients with Multiple Sclerosis. [Display omitted] • The complementary use and utility of molecular and elemental imaging techniques in brain research is demonstrated. • Lesions of two deceased multiple sclerosis patients were explored tentatively. • MALDI-MSI and IR imaging were used to investigate lipid distributions in and around lesions. • LA-ICP-ToF-MS and XRF were used to investigate distributions of endogenous and xenobiotic elements. • Distributions of selected trace elements were calibrated with mould-prepared gelatine standards. [ABSTRACT FROM AUTHOR]

Elemental imaging gives insight into the fundamental chemical makeup of living organisms. Every cell on Earth is comprised of a complex and dynamic mixture of the chemical elements that define structure and function. Many disease states feature a disturbance in elemental homeostasis, and understanding how, and most importantly where, has driven the development of laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) as the principal elemental imaging technique for biologists. This review provides an outline of ICP-MS technology, laser ablation cell designs, imaging workflows, and methods of quantification. Detailed examples of imaging applications including analyses of cancers, elemental uptake and accumulation, plant bioimaging, nanomaterials in the environment, and exposure science and neuroscience are presented and discussed. Recent incorporation of immunohistochemical workflows for imaging biomolecules, complementary and multimodal imaging techniques, and image processing methods is also reviewed. [ABSTRACT FROM AUTHOR]

• Four dimensional PFAS analysis using UHPLC-IMS-QTOF-MS. • Simultaneous targeted and non-targeted analysis of PFAS in water samples. • Development of an automated data processing workflow combining mass defect and fragment ion flagging. • Ion mobility mass spectrometry separated and identified isomers. • The developed method reduced complexity of analyses and identified potential PFAS. Per- and polyfluoroalkyl substances (PFAS) represent a large group of synthetic organic compounds which exhibit unique properties and have been extensively used for consumer and industrial products, resulting in a widespread presence in the environment. Regulation requiring PFAS monitoring has been implemented worldwide due to their potential health and eco-toxicological effects. Targeted methods are commonly used to monitor between twenty to forty PFAS compounds, representing only a small fraction of the number of compounds that may be present. Consequently, there is an increasing interest in complementary non-targeted methods to screen and identify unknown PFAS compounds with the aim to improve knowledge and to generate more accurate models regarding their environmental mobility and persistence. This work details the development of a method that simultaneously provided targeted and non-targeted PFAS analysis. Ultra-high performance liquid chromatography (UHPLC) was coupled to ion mobility-quadrupole time of flight-mass spectrometry (IMS-QTOF-MS) and used to quantify known and screen unknown PFAS in environmental samples collected within the greater Sydney basin (Australia). The method was validated for the quantification of 14 sulfonate-based PFAS, and a non-targeted data analysis workflow was developed using a combination of mass defect analysis with common fragment and neutral loss filtering to identify fluorine-containing species. The optimised method was applied to the environmental samples and enabled the determination of 3–7 compounds from the targeted list and the detection of a further 56–107 untargeted PFAS. This simultaneous analysis reduces the complexity of multiple analyses, and allows for greater interrogation of the full PFAS load in environmental samples. [ABSTRACT FROM AUTHOR]

Gd-based contrast agents (GBCAs) are frequently administered to patients for magnetic resonance imaging to enhance tissue contrasts. After examination, they are excreted and enter surface waters via local wastewater treatment plants' effluents where they lead to anthropogenic Gd anomalies in the environment of metropolitan areas with developed healthcare. This work presents the speciation analysis of GBCAs in water samples from Australia by targeting individual GBCAs in effluent, river and seawater samples obtained from New South Wales (Sydney area), the Northern Territory (Alice Springs) and Victoria (Melbourne area). A method based on hydrophilic interaction liquid chromatography (HILIC) coupled to inductively coupled plasma-mass spectrometry (ICP-MS) provided rapid separation and quantification of four common GBCAs in under three minutes. To improve the sensitivity, ion extraction and transport processes were optimised and the quadrupole mass filter was operated with an increased mass bandpass, decreasing limits of detection to between 18 and 24 ng L−1 for individual GBCAs. This allowed detection of Gd-DOTA, Gd-BT-DO3A and Gd-DTPA-BMA at concentrations of up to 160 ng L−1 in water samples collected from rivers within the proximity of effluents of local wastewater treatment plants. The analysis of GBCAs in oceanic sea water required the development of a novel automated micro-solid phase extraction (μSPE) method for matrix elimination and analyte pre-concentration enabling the detection of Gd-DOTA and Gd-BT-DO3A. [ABSTRACT FROM AUTHOR]

Standard preparation for elemental bio-imaging by laser ablation-inductively coupled plasma-mass spectrometry is confounded by the chemical and physical differences between standard and sample matrices. These differences lead to variable ablation, aerosol generation and transportation characteristics and must be considered when designing matrix-matched standards for reliable calibration and quantification. The ability to precisely mimic sample matrices is hampered due to the complexity and heterogeneity of biological tissue and small variabilities in standard matrices and sample composition often negatively impact accuracy, precision and robustness. Furthermore, cumbersome preparation protocols may limit reproducibility and traceability. This work presents novel facile methods for the preparation of gelatine standards using both commercial and laboratory-made moulds. Surface roughness, thickness and robustness of the mould-prepared standards were compared against cryo-sectioned gelatine and homogenised brain tissue standards. The mould-prepared standards had excellent thickness accuracy and signal precision which allowed robust quantification, were easier to prepare and therefore easier to reproduce. We also compared gelatine standards prepared from a variety of animal sources and discuss their suitability to calibrate low level elemental concentrations. Finally, we present a simple method to remove background metals in gelatine using various chelating resins to increase the dynamic calibration range and to improve limits of analysis. [ABSTRACT FROM AUTHOR]

Human zinc deficiency increases susceptibility to bacterial infection. Although zinc supplementation therapies can reduce the impact of disease, the molecular basis for protection remains unclear. Streptococcus pneumoniae is a major cause of bacterial pneumonia, which is prevalent in regions of zinc deficiency. We report that dietary zinc levels dictate the outcome of S. pneumoniae infection in a murine model. Dietary zinc restriction impacts murine tissue zinc levels with distribution post-infection altered, and S. pneumoniae virulence and infection enhanced. Although the activation and infiltration of murine phagocytic cells was not affected by zinc restriction, their efficacy of bacterial control was compromised. S. pneumoniae was shown to be highly sensitive to zinc intoxication, with this process impaired in zinc restricted mice and isolated phagocytic cells. Collectively, these data show how dietary zinc deficiency increases sensitivity to S. pneumoniae infection while revealing a role for zinc as a component of host antimicrobial defences. [ABSTRACT FROM AUTHOR]

The discharge of plastic waste and subsequent formation and global distribution of microplastics (MPs) has caused great concern and highlighted the need for dedicated methods to characterise MPs in complex environmental matrices like seawater. Single particle inductively coupled plasma – mass spectrometry (SP ICP-MS) is an elegant method for the rapid analysis of nano- and microparticles and to characterise number concentrations, mass, and size distributions. However, the analysis of carbon (C)-based microstructures such as MPs by SP ICP-MS is at an early stage. This paper investigates various strategies to improve figures of merit to detect and characterise MPs in complex matrices, such as seawater. Ten methods operating distinct acquisition modes with various collision/reaction gases, tandem MS (ICP-MS/MS) and targeting 12C or 13C were developed and compared for the analysis of polystyrene-based MPs standards in ultra-pure water and seawater. The robust analysis of MPs in seawater was accomplished by on-line aerosol dilution enabling repeatable size calibration while minimising drift effects. However, the direct analysis of seawater decreased ion transmission and required matrix-matching for accurate size calibration. Analysis of the 12C isotope instead of 13C improved the size detection limits (sDL) to 0.62 μm in ultra-pure water and to 0.96 μm in seawater. ICP-MS/MS methods decreased ion transmission but also reduced background signal and increased selectivity, particularly in the presence of spectral interferences. In the second part of this study, it was demonstrated that the developed methods were applicable for the analysis of C in unicellular organisms and allowed calibration of physical dimensions. This is relevant for the investigation and understanding of phenotypical traits associated, for example, with climate change resilience as well as oceanic C storage. SP/SC ICP-MS was employed to target five different intact Symbiodiniaceae algae strains with diverse life-histories in seawater and polystyrene-based MPs were used to calibrate cellular C masses, which were between 51 and 83 pg. The C mass distribution across the analysed unicellular cells was used for modelling cell sizes, which were in the range of 7.6 and 10.1 μm. Determined values were in line with values obtained with complementary techniques (Coulter-counting, total organic C analysis and microscopic analysis). [Display omitted] • SP/SC ICP-MS method development and application for the individual analysis of C-based microstructures in seawater. • Matrix-matching and on-line aerosol dilution for robust mass and size characterisation of microplastics. • Size detection limit for polystyrene-based microplastics is improved to 0.6 μm. • Developed methods are applied for the direct analysis of carbon in unicellular algae in seawater. • C mass distribution and cellular sizes of unicellular algae are determined via SP and SC ICP-MS. [ABSTRACT FROM AUTHOR]