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This update covers the literature published between approximately June 2021 and May 2022 and is the latest part of a series of annual reviews. It is designed to provide the reader with an overview of the current state of the art with respect to the atomic spectrometric analysis of various metals, chemicals and materials. These materials include ferrous and non-ferrous metals, glasses, polymers, ceramics, engineered nanostructures, fuels, nuclear materials, building materials, catalysts and electronic components. Also included is the analysis of forensic samples such as explosives and gunshot residue. It is not a comprehensive review of all papers that have used an atomic spectrometric technique. Instead, it includes only those papers that have some novelty through making an advance in either knowledge or the application of atomic spectrometry. Those papers that maximise the information gleaned from analytical data, e.g. the provenance of cultural heritage or forensic samples, through the use of chemometric analysis will also be included. [ABSTRACT FROM AUTHOR]

This update covers the literature published between June 2020 and May 2021 and is the latest part of a series of annual reviews. It is designed to provide the reader with an overview of the current state of the art with respect to the atomic spectrometric analysis of various metals, chemicals and materials. It is not designed to be a comprehensive review of all papers that have used an atomic spectrometric technique. Instead, it includes only those papers that have some novelty through making an advance in either knowledge or the application of atomic spectrometry. Also included, especially for forensic-based applications, for recycling applications and for cultural heritage samples, are those papers that have treated the analytical data produced with chemometric packages to provide invaluable information on provenance or to aid identification. Other research has focussed on calibration strategies for LIBS analyses and improving the resolution of depth and lateral profiling to facilitate the elucidation of mechanistic aspects of electronic components. An additional topic of interest includes the identification of oxidation states and neighbouring atoms using techniques such as XPS and XANES, again attempting to elucidate mechanisms for electronic components or to elicit speciation data. [ABSTRACT FROM AUTHOR]

This review has been modified somewhat compared with its predecessors in that the cultural heritage applications have been grouped together in their own section rather than being split between assorted other sections throughout the review. Hopefully, this will enable readers interested in that topic to locate all of the relevant papers more easily. There is no doubting that laser induced breakdown spectrometry (LIBS) is still the most rapidly expanding technique of interest for "industrial" samples. Its use for on-line or standoff analysis covers many topic areas including the metals production, scrap metal and plastic sorting industries, nuclear applications, in situ analysis of remote systems, e.g. power cable insulators, etc. It is also regarded as being minimally damaging to samples and has therefore found extensive use in the analysis of cultural heritage samples; especially when used in conjunction with chemometric tools to identify provenance or chronology. For the analysis of fuels, it was disappointing to see so many papers re-inventing the wheel, with numerous applications being published that offer little improvement on existing standard methods. In many cases, the protocols described were very lengthy or complicated and succeeded only in obtaining a similar result to an existing method, but with poorer precision and with no benefit to the end user. Other areas, e.g. catalysts has a huge amount of interest. However, the techniques used to characterise the materials are mature and often, many of the papers published do not discuss the analytical science in any detail. The analysis of pharmaceuticals and personal care products has had a large increase in research interest during this review period. This is potentially because of traditional methods, e.g. atomic absorption, slowly being replaced by more modern techniques, e.g. ICP-MS. Other growth areas of research have been the analysis of thin films, semiconductors and solar cells. Here, it is often X-ray-based analytical methods that are most commonly used, although some depth-profiling applications will use either LIBS or LA-ICP-MS. Another very popular area of research is that of nanoparticles. Here, the research focus has shifted from toxicological studies to the analysis of nanoparticles being used as carriers for drugs. This area is likely to increase further over the coming years. Consequently, analytical methods have also changed from using field flow fractionation to X-ray-based techniques such as XPS and XANES that describe the chemical composition of the particles rather than their size. Single particle ICP-MS for particle sizing is still an area of interest though. [ABSTRACT FROM AUTHOR]

There has been a large increase in the number of papers published that are relevant to this review over this review period. The growth in popularity of LIBS is rapid, with applications being published for most sample types. This is undoubtedly because of its capability to analyse in situ on a production line (hence saving time and money) and its minimally destructive nature meaning that both forensic and cultural heritage samples may be analysed. It also has a standoff analysis capability meaning that hazardous materials, e.g. explosives or nuclear materials, may be analysed from a safe distance. The use of mathematical algorithms in conjunction with LIBS to enable improved accuracy has proved a popular area of research. This is especially true for ferrous and non-ferrous samples. Similarly, chemometric techniques have been used with LIBS to aid in the sorting of polymers and other materials. An increase in the number of papers in the subject area of alternative fuels was noted. This was at the expense of papers describing methods for the analysis of crude oils. For nanomaterials, previous years have seen a huge number of single particle and field flow fractionation characterisations. Although several such papers are still being published, the focus seems to be switching to applications of the nanoparticles and the mechanistic aspects of how they retain or bind with other analytes. This is the latest review covering the topic of advances in the analysis of metals, chemicals and materials. It follows on from last year's review 1–6 and is part of the Atomic Spectrometry Updates series. [ABSTRACT FROM AUTHOR]

This ASU review focuses on developments in applications of atomic spectrometry to the characterisation of metals, chemicals and functional materials. While each of these application categories is very distinct in terms of the analytical challenges posed, there are a number of common themes than can be identified from an examination of the relevant literature appearing over the review period. The traditional atomic spectrometry techniques (e.g. AAS, OES, XRF, ICP-MS) are relatively mature, but reports continue to appear that seek to address perceived limitations in sensitivity in certain applications, but increasingly more frequently in relation to sample handling and preparation/extraction methodologies, validation and creation of SRMs and methods. However, it is equally clear that because of that very maturity such techniques are more often cited as analytical reference methods to support the development of other approaches (e.g. GD-OES, GD-MS, PIXE, PIGE, RBS, SEM-EDS, SIMS, TXRF, micro- and macro-XRF, XAS, XPS) that provide either direct sampling or depth and lateral elemental profiling capabilities. Consequently, a variety of techniques may now be routinely applied within an individual study to characterise samples to the extent it is hard to comment critically on the particular analytical novelty that lies at the heart of the work. It is fair to say that in some cases, the significance of the research now involves revealing the features of the sample (including examining surface modifications, coatings, thin films and multilayers, or even the characteristics of a device, functional component, or object, or complex mixture) rather than in the development of the analytical approach itself. That said, certain trends in technique development still expand the range of applications that can be addressed. For example, interest in LIBS continues to command attention and is heavily cited in most application sections of this review. The technique offers certain unique advantage for elemental analysis in rapid direct sampling, portability and operating in remote and harsh environments (including industrial production) where low level detection is not essential. Clearly sensitivity remains the Achilles' heel for LIBS but developments in measurement technique such as pulse delay are resulting in better optimised procedures. The development in laser solid sampling technology is providing benefits applicable to other techniques such as ICP-MS and newer variants such as laser ionisation MS. Indeed, lasers, flames, plasmas and other electrical discharges have been used regularly in the fabrication of samples. The atomic spectrometry techniques with which they have been associated are now employed to study such production processes in situ. The development of nanomaterials has given rise to new approaches to particle size distribution and single particle characterisation where the atomic spectrometric determination produces a size rather than a concentration. There is evidence too in the review of research work going on to understand the environmental consequences of the widespread use of new technologies using data analysis approaches to examine source, provenance or impact. Consequently, while the fundamental analytical questions: “What?” and “How much?” continue to be relevant to researchers increasingly these must now be qualified in many situations by providing answers to enquiries such as “Where?” and “How big (or small)?”. [ABSTRACT FROM AUTHOR]

There has been significant progress in the use of laser induced breakdown spectrometry (LIBS) as a method of monitoring steel production in real time. This has the benefits of both time and cost saving. There has been a drop in the number of papers reporting methods for the analysis of fuels. This may be a function of the drop in oil prices leading to reduced finance for research. However, the determination of S is one of the hot topics in this sample type. This is possibly a consequence of companies attempting to meet the increasingly strict regulations on S emissions. Analytical methodology, e.g. LA-ICP-MS, LIBS or XRF, which produces minimal damage to the samples is still increasingly popular. This is especially true for historical or archaeological sample types, e.g. paintings, pottery and old documents; but is also applicable to forensic materials. Often, with these sample types, the analytical data are then treated using chemometrics packages so that provenance may be determined or patterns detected. Similar methodology was used for the identification of different plastics types, facilitating sorting and re-cycling. The analysis of nanoparticles is an increasingly popular subject area. Simple introduction of samples containing nanoparticles through a standard nebuliser/spray chamber sample introduction system is often complicated by the particles agglomerating. This leads to under-estimations of the concentrations present. Single particle analysis has continued to be a popular research area with real samples now being extracted and analysed rather than standard solutions. Similarly, field flow fractionation coupled with ICP spectrometry (sometimes also in conjunction with single particle analysis) has also been used to characterize nano-particulates and to distinguish between particulate and ionic species. [ABSTRACT FROM AUTHOR]

The article presents a review that covers developments in the analysis of chemicals, metals and functional materials. Topics discussed include the use of chemometrics for removing substrate interferences, advances in the analysis of nanomaterials and single particles, and the importance of depth profiling of semiconductor materials.