The future of elemental analytical chemistry – the sixth special issue dedicated to young analytical scientists

Björn Meermann

Björn Meermann, born in 1982, studied chemistry at the University of Münster and obtained his doctorate in 2009 in the working group of Prof. Dr Uwe Karst. This was followed by a postdoctoral period of almost two years at the University of Ghent (Belgium) in the working group of Prof. Dr Frank Vanhaecke. In 2012 he joined the Federal Institute of Hydrology (BfG) in Koblenz as a research associate and postdoctoral researcher. Since June 2019, Björn Meermann has been Head of Division 1.1 “Inorganic Trace Analysis” at the Federal Institute for Materials Research and Testing (BAM) in Berlin and “Habilitand” in Analytical Chemistry at the Humboldt-University in Berlin. Since 2020 Björn Meermann has been a member of the Editorial Board of JAAS. Dr Meermann’s research is located at the interface between materials, and the natural environment and life sciences. He investigates the release of elements or elemental species and (nano)particles from materials into the environment and their possible uptake by organisms and cells, with the aim of assessing the influence of (metal based) materials on the environment. Analytical techniques applied for his research are: hyphenated techniques (CE/, LC/, GC/ICP-MS), single particle/cell-ICP-ToF-MS and HR-CS-GFMAS for non-metal analysis.

This Journal of Analytical Atomic Spectrometry (JAAS) special issue is dedicated to young analytical scientists (YAS) – it highlights the work of outstanding young scientists in atomic spectrometry and related areas. Following the success of previous YAS special issues, organized by Jorge Pisonero (2017), Carsten Engelhard (2014) and Spiros A. Pergantis (2010, 2006 and 2002), this is the sixth special issue dedicated to YAS. Authors are either outstanding graduate students, postdoctoral fellows, researchers in their first industrial appointment or young analytical faculty. Each author was nominated by worldwide experts in the field including members of the Editorial Board and Advisory Board of JAAS.

In 2014, I also got the chance to contribute as an author in the YAS issue of JAAS. Seven years later, it is my great honour to be the guest editor of this special issue dedicated to YAS in JAAS. This year’s YAS issue contains 13 research/review articles covering the fields of micro- and nanoparticle analysis, elemental imaging, isotope analysis, new methods for trace metal analysis, and speciation analysis.

The field of particle analysis/sp-ICP-MS is covered by articles highlighting the current state in micro and nanoplastic analysis as well as applications of sp-ICP-MS in the field of medicinal applications. A shift to complex matrices is observable.

Velimirovic et al. (10.1039/D1JA00036E) provide a critical view on the current state of mass spectrometric based methods for the characterization of airborne micro- and nanoplastics. The authors identified a lack of knowledge on the sources of micro- and nanoparticles – levels, health impact; mainly related to a lack of appropriate analytical methods for identification, quantification and size-determination. Furthermore, strategies for sampling and sample preparation are missing. State of the art analytical methods are highlighted and critically discussed. The authors concluded that single methods are not appropriate in the field of micro- and nanoplastics research. Abad-Alvaro and co-workers (10.1039/D1JA00068C) address the analysis of silver nanoparticles in medicinal matrices. Silver nanoparticles comprise antibacterial and antimicrobial properties – thus, they are also in use in medicinal devices. However, despite their beneficial properties nanoparticles/ions might be released into the blood stream and potentially cause negative effects. In particular appropriate sample preparation protocols for nanoparticles from complex (biological) matrices are needed. Enzymes are often in use, but are rather expensive. Thus, the authors developed a method based on the alkaline digestion for silver nanoparticle analysis in blood samples – samples are preserved for several days. Further work, also related to the field of medicinal applications of sp-ICP-MS came from Lv et al. (10.1039/D0JA00464B). Gold nanoparticle tagged immunoassays were used for biomarker detection of pancreatic cancer. Tagged immunoassays were detected via sp-ICP-MS and successfully applied for serological evaluation of patients.

In contrast to the intended use of nanoparticles in e.g., medicine, an accidental release of nanoparticles (NPs), e.g., from metal-based implant material in surrounding tissues or human body must be prevented. Metal based dental implants are widely applied. Titanium-based materials are in use, however, metal-based implants can undergo so called “tribocorrosion” and released NPs can interact with cells. To end up with safe materials, appropriate analytical techniques are needed. Corte-Rodriguez et al. (10.1039/D1JA00154J) developed single particle/cell-ICP-MS methods and investigated the release of Ti-NPs from dental implants as well as possible interaction with cells/bacteria. Although Ti-based materials are considered to be inert materials, the release of heterogenous NPs was observed by the authors. Furthermore, the uptake of released NPs by cells/bacteria was observed – these findings underly the need for further studies and powerful ICP-MS based methods to end up with safe implant materials.

A further large and well-established field is elemental imaging. Next to a plethora of applications, instrumental developments regarding, e.g., new ablation chamber design, are still ongoing topics.

Elemental imaging provides spatially resolved elemental information on various sample-surfaces. However, one drawback is a long analysis time – in particular when larger sample objects are analyzed. Thus, a current trend is the combination of fast-ablation cells and “fast” ICP-(ToF)-MS systems for multi-elemental imaging in short transient signals. Van Acker et al. (10.1039/D1JA00110H) developed a low-dispersion aerosol transport system. Their setup maximizes the collection of ablated aerosol particles and ensures a high transport efficiency while minimizing aerosol dispersion of particles during their path through the transport tubing. The combination of their setup with low-dispersion ablation cells paves the way to kHz pixel acquisition rates. Next, spatially resolved quantitative elemental information – the combination of laser ablation and multicollector-ICP-MS (LA/MC-ICP-MS) allows for spatially resolved isotope information. Metals play an important role in all kinds of life processes – once metabolism of metals is impaired, dysfunction within the organism might occur. An example is disordered copper metabolism – Morbus Wilson disease. Copper is concentrated in tissues and organs leading to damage. Early diagnosis is essential – thus, García-Poya et al. (10.1039/D0JA00494D) developed a LA/MC-ICP-MS based approach for isotope analysis of patient’s serum samples. Isotope shifts are used as a tracer for Morbus Wilson disease.

Lithium (Li) is considered to be an essential element – Li comprises two stable isotopes which have been intensively studied in terms of climate, weathering and geological processes. However, only a few studies regarding Li isotope investigations in biological systems exist. Furthermore, a lack of reference materials with an organic-rich matrix and known Li isotope ratios are available. Appropriate reference materials are of utmost importance to end up with reliable data for, e.g., tracing biological processes. Thus, Thibon et al. (10.1039/D1JA00045D) characterized reference materials of biological origin regarding Li concentration as well as δ⁷Li values by means of MC-ICP-MS. In future, the developed method for hard or soft tissue materials as well as data published will impact important research fields, e.g., ecotoxicology, biomedicine.

An ongoing field is the development of new techniques and methods for sensitive “bulk” elemental analysis in complex matrices – in particular in environmental and food monitoring.

Another ongoing trend is the miniaturization of all kinds of system. Thus, also in the field of elemental analysis portable and cheap systems are beneficial – in particular “on-site” analysis in the research fields of, e.g. environmental analysis or process analysis, is of high relevance. He et al. (10.1039/D1JA00039J) developed a micro-plasma system in conjunction with a small spectrometer. The system showed high sensitivity and was applied for the analysis of As, Hg and Pb in reference materials, but also surface water samples. An important type of sample is foodstuff – Gao et al. (10.1039/D1JA00037C) developed an optimized digestion method for Cd analysis in rice based on a Fenton-line reaction. As well as the reduction of digestion chemicals, time was also decreased. Matczuk et al. (10.1039/D0JA00492H) developed an extraction procedure for metals from barley grass based on natural deep eutectic solvents (NADES). NADES are an interesting alternative to classical organic solvent extraction – higher extraction efficiencies were obtained; furthermore, NADES are non-toxic and “green” chemicals. A further interesting sample preparation method for the analysis of selenium in fish samples was developed by Gois et al. (10.1039/D1JA00091H). They applied magnetic nanoparticles for the preconcentration of Se. Graphene oxide was incorporated onto magnetic iron nanoparticles facilitating the separation by means of a magnet upon preconcentration of Se onto the graphene oxide phase. Se detection at the ng g⁻¹ level has been achieved.

Speciation analysis is a fixed component of elemental analysis – only speciation analysis allows for a mechanistic understanding of the behavior of metals in the environment as well as living organisms.

Braeuer et al. (10.1039/D0JA00518E) took a closer look at fly agaric mushrooms – herein vanadium species (such as amavadin) are present – the biological role of these species is unknown and analytical methods are lacking. Thus, the authors developed a HPLC/ICP-MS based method for vanadium speciation – they deployed the method to fruit-body extracts of fly agaric mushrooms and found, next to amavadin, further V-species. Their method will help elucidate the (up to now largely unknown) role of vanadium in the environment. Next to the naturally occurring elemental species in the environment, several anthropogenic species occur in e.g. surface waters. Clases et al. (10.1039/D0JA00493F) applied speciation analysis for the investigation of gadolinium-based magnetic resonance imaging (MRI) contrast agents in surface water. To enhance sensitivity, the authors operated the ICP-MS with an increased mass bandpass – LODs in the low ng L⁻¹ range were achieved. Automated micro-solid phase extraction allowed for analysis of sea water samples as well.

I would like to thank all well established and prominent colleagues from the community for their nominations of young analytical scientists, which was key for this successful YAS special issue. Furthermore, many thanks to all the young analytical scientists for their contribution, and I would like to wish you all success with your ongoing and future scientific career.

Special thanks to the JAAS Editorial Staff members, in particular Ziva Whitelock for her great support and organization – many thanks!

Björn Meermann

Head of Division 1.1 – Inorganic Trace Analysis @ BAM

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