21 years of fundamental and applied research in JAAS

Detlef Günther is Associate Professor for Trace Element and Micro Analysis at the ETH Zürich in the Laboratory of Inorganic Chemistry. He became a member of the Advisory Board of JAAS in 2002 and joined the Editorial Board in 2005. Dr Günther’s research interests include direct solid analysis using laser ablation at different wavelengths and pulse durations coupled to various ICP mass spectrometers, transport and excitation mechanisms of laser generated aerosols, suppression of interferences using various collision and reaction cell technologies and, more recently, fundamental and applied research using glow discharge TOFMS.Celebrating the 21st anniversary of JAAS and considering the number of papers (3724)¹ published in this period, I thought it might be of interest to evaluate the contents of these papers in more detail. Therefore, we reviewed the existing issues to discover how many different research topics have been published in JAAS and how the techniques developed from 1986 until 2005. We specifically looked at the relationship between fundamental (hardware, fundamental processes and method developments) and applied research, tried to highlight the trends of the major techniques in atomic spectrometry and to evaluate major fields of application. The evaluation scheme was based on instrumentation, fundamental versus applied aspects, area of application, etc. It needs to be mentioned that this search has been carried out within my research group (individual years have been assigned to each group member). Therefore, the statistics may be affected by personal judgments.

Reviewing such a large number of papers takes quite some time. However, several early editorials, interviews and trend predictions have caught my attention and reading them under the current perspective makes them even more interesting. In an early interview, for example, Jean Michel Mermet² (CANAS 1986) expressed his happiness about the fact that he participated early on in new developments of ICPs in atomic spectroscopy. His positive arguments expressed his excitement about working on a new technique and every experiment was a new discovery. He also mentioned that “the bibliography was quickly searched because only few papers had been published on this topic”. Today’s situation is definitely different and despite the ease of accessing literature via the internet today, which makes every published article (even before publication) immediately available, it is much more difficult to maintain a comprehensive overview of current research. The number of papers is increasingly difficult to follow for all of us, but especially for those just joining this field of research. Considering 3724 manuscripts¹ published within the past 20 years would mean that every scientist working in the field since 1986 would have to have read one article every second day (including Saturdays and Sundays). Even if this effort has been taken, one needs to remember that JAAS is only one out of more than 10 journals dealing with atomic spectroscopy. That makes more than 10 to be read per day. Since “omics” has now become another key word added to atomic spectroscopy, I do not want to speculate how much this will increase the hours spent reading. Of course such “reading efforts” are not realistic and this implies that we have to become more and more selective and specialized. However, it also underlines the importance of interdisciplinarity.

Reviewing JAAS also indicates that predicting the future lost popularity. In the late 1980s it was once implemented in the conclusions of a critical review. Gary Hieftje, the inventor of the Smith and Hieftje background correction³ predicted that AAS papers will drop below zero before the year 2000.⁴ His humorous third-order polynomial prediction was theoretically correct, but realistically wrong. However, shortly after his review (see 1989–1991, Fig. 1), the number of AAS-related manuscripts decreased rapidly.

Fig. 1 Development of AAS publications between 1986 and 2005.

How much of this was caused by Gary’s comments would require a thorough investigation. In any case we should accept that most techniques, including AAS, will in a way exist “forever”, because the Star Trek Tricorder is still out of reach. Furthermore, even today, most students will receive training on this technique. Just in case that somebody is interested in a safety instruction for flame-AAS, I would like to refer to an editorial by M. Cresser from 1988,⁵ which is written with care and humour appropriate to instructing new students.

Over the last 20 years, 1648 manuscripts on fundamentals and 1936 manuscripts on applications have been published in JAAS and the most dominant atomization/excitation techniques have been graphite furnace and flame AAS, inductively coupled plasma optical emission spectrometry and inductively coupled plasma mass spectrometry.

The number of AAS papers has decreased over the last 20 years (50% to 10% of all manuscripts) and the last couple of years have been dominated by applications (Fig. 2).

Fig. 2 Fundamental versus applied papers of AAS.

ICP-OES, a widely used technique for routine analysis, had a successful period from 1986 until 1996 (see Fig. 3). Surprisingly, to me, the total number of ICP-OES papers has always been lower than the number of AAS papers and it is hard to imagine that this will change.

Fig. 3 Fundamental and applied papers in ICP-OES.

ICP-MS appeared in the journal instantly in 1986 and is currently the technique that provides the highest number of publications. Approximately 30% of all manuscripts deal with topics involving ICP-MS, ranging from matrix effects, interferences, ion transmission to different sample introduction systems. Since 1993 the ratio between the fundamental and applied research has remained almost constant (approximately 1∶2, except 1999). Over the last 20 years, 5 different types of ICP mass spectrometers have been introduced (ICP-QMS, ICP-SFMS, ICP-TOFMS, MC-ICP-MS, and ICP-MS with reaction cell technology). The articles published in JAAS to some extent reflect the developments in the higher ratio of fundamental versus applied papers (Fig. 4). For example, 1999 shows a peak in fundamental papers, which followed the introduction of commercial reaction cell and TOF instruments. The last 3 years show a notable increase in papers dealing with MC-ICP-MS. For all those who have recently started to work with ICP-MS I recommend to read the historical development of this technique by Alan Gray published in 1986.⁶ It summarizes how this technique was born and what effort has been necessary to develop it into a successful tool for elemental analysis and isotope ratio measurements. Furthermore, it should remind us that a thorough evaluation of “most severe drawbacks and missing capabilities” could always be a starting point for new instrumentation.

Fig. 4 Fundamental and applied papers in ICP-MS.

Fig. 5 Most prominent applications areas (average over 20 years, all techniques included).

The number of fundamental and applied studies in GD-OES and GD-MS is growing. Frequent special issues, however, cause a rather sinusoidal curve in the number of papers per year.

The major applications (which we selectively restricted to 9 major topics) indicate that environmental/speciation and bio related researches are today’s most prominent research areas (Fig. 5). The last 10 years have seen a significant increase in speciation-related research. Materials science and geological applications remained almost constant over the 20 years. In terms of application, almost every element has been studied in an incredible variety of matrices using all types of instrumentation. However, there is a tendency to validate previous research by repeating experiments with minor changes to the set up (one might also say that the wheel has been reinvented a few times …). Therefore, we should not always consider comments like “we did this many years ago” as a history lesson or arrogance. The phrase “20 hours in the lab saves you 1 hour in the library” is fundamentally true, but should be considered in the opposite sense!

Fig. 6 Percentage of papers per technique and year (considering techniques above 10% of the total number of papers).

The manuscripts contributed to JAAS over 20 years are 57% from Europe, 24% from North America, 12% Asia, 4% South America, 1.6% Australia and 1.6% Africa. The contribution of Asia has been almost constant (12% to the total papers per year)—however, I am sure that this will change in the near future. JAAS was launched as an international journal, yet since it is based in the UK it is not surprising that the “UK contribution” has been 11% (of all published papers): this is not the highest contribution of a single country (USA is 18%). The distribution among nations further indicates that JAAS is truly international. The ratio between the European and North American papers remained around 2.4 (RSD = 30%) throughout JAAS’ first 20 years. The most frequently word used in the titles of JAAS articles is “Determination” and, of course, much more statistical detail could be given.

However, I will not finish without discussing the research topic I am most interested in. As already indicated by D. Koppenaal, LA-ICP-MS was also amongst the hot topics in JAAS. In 2005, the number of LA-ICP-MS nearly reached the number of AAS publications (Fig. 6) and I predict that the positive trend in number of publications per year will continue. Since this technique started as a niche application (early 1990s, few papers), it has passed different stages of acceptance and is now contributing to exciting research. However, its full potential has not yet been reached. There might come a day when all ICP-MS systems will be coupled to laser ablation “nebulizers”. The driving force is obvious—simple set up, rapid results, surprises included. However, before this time, we will still digest a lot of samples. Good recipes have been published, especially in the early days of JAAS. We “simply” have to transfer them into our modern laboratories.

Acknowledgements

The search necessary for this editorial was important to be finished before the World Cup finals and took significant time of all PhD students and postdocs. Therefore, I would like to acknowledge the contributions from Barbara, Bodo, Beni, Christian, Christopher, Daniel, Gisela, Ivana, Joachim, Jorge, Karin, Markus, Martin, Robert.

Detlef Günther

References

1. D. W. Koppenaal, J. Anal. At. Spectrom., 2006, 21, 259–262.
2. J. M. Mermet, J. Anal. At. Spectrom., 1986, 1, 401–403.
3. S. B. Smith, Jr and G. M. Hieftje, Appl. Spectrosc., 1983, 37, 419–424.
4. G. M. Hieftje, J. Anal. At. Spectrom., 1989, 4, 112–117.
5. M. Cresser, J. Anal. At. Spectrom., 1988, 3, 299–301.
6. A. Gray, J. Anal. At. Spectrom., 1986, 1, 403–405.

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