Geostandards and Geoanalytical Research Bibliographic Review 2018

The GGR bibliographic review is specifically designed to give an overview of publications of the past year (in this case 2018) and presents analytical data for established and widely used reference materials (RMs) and certified RMs (CRMs), and highlights recently developed and characterised RMs. This research involves the careful examination of about 8400 publications from twenty scientific journals in the fields of analytical chemistry, geochemistry, palaeoclimate research and environmental research. About 630 of these publications contain analytical data for RMs (Table 1, Figure 1). These analytical values are included in the GeoReM database (Jochum et al. 2005; http://georem.mpch-mainz. gwdg.de). GeoReM is freely accessible to the scientific community and provides published analytical, compiled and certified values of RMs, which are important in geoanalysis and related scientific fields. All publications of 2018 included in GeoReM are listed in Appendix S1. The reference citation is preceded by a key code: the first two digits stand for the year of publication (here: 18) followed by the serial number for the specific year and the GeoReM‐ID, which allows easy access to the GeoReM database. Every entry is followed by a concise summary of the elements/ isotopes for which measurement results are published, as well as the relevant reference materials and their producers. An overview of the names and abbreviations of reference material providers is given in Appendix S2.

More than 50% of the publications provide data on radiogenic or stable isotopes, whereas less than 10% present data sets for major elements and 16% substantial data sets for trace elements (Figure 1). Some 25% of the papers publish data just for a very few selected elements. Additional to the classical isotopic systems such as Sr, Pb or Nd, various isotopic systems have become more important and measurement results for them have been enabled by progress in analytical techniques (Linge et al. 2017).
A comparison of the surveyed journals shows the high impact of GGR, which has, as in former years (Weis et al. 2018), at 71% the highest proportion of publications containing analytical data for RMs, followed by Lithos with 27% and Journal of Analytical Atomic Spectrometry with 23% ( Figure 2). In absolute numbers, Lithos and Chemical Geology deliver the main contributions to this review with 100 and 85 publications in 2018, respectively (Figure 3, Table 1). Figure 4 shows the number of papers in 2018, which contain data for RMs of the most common providers. The largest numbers of published data in The importance of isotopic systems in geochemistry and related fields is confirmed by the introduction of new isotopic RMs as well as by substantial isotopic studies on numerous RMs, which are presented in 2018. In the following paragraphs, some examples are shown. Richter et al. (2018) prepared and certified with IRMM-2019-2029 a set of uranium nitrate solutions. The JMC 3-0749L Zn solution for Zn isotopes is nearly exhausted. Therefore, a new RM as a replacement is urgently needed. A zinc metal reference material from NIST -NIST SRM 683was analysed for its isotopic composition and calibrated as a new reference material for Zn isotope analysis by Yang et al. (2018). Also, there is a lack of data sets for Se isotopes, which is why Yierpan et al. (2018) determined Se and Te with isotope dilution ICP-MS (ID-ICP-MS) and double-spike MC-ICP-MS in several RMs. ID-(MC)-ICP-MS was also used for the determination of In and Sn in sixteen geological RMs by Kirchenbaur et al. (2018).
As there is a need of molybdenum RMs, Liu et al. (2018) performed a preparation and characterisation of CRMs of three molybdenum ores (GBW07141 to GBW07143, abbreviated as GMo-1 to GMo-3) and one molybdenum concentrate (GBW07144, abbreviated as GMo-4) with certified values for up to twenty-six elements.
A large number of papers publish data for zircon reference materials such as zircon 91500 from HMM (Harvard Mineralogical Museum, USA; Wiedenbeck et al.

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In many 2018 publications, the applications for widely used RMs are increased by characterising new parameters, especially stable isotopic compositions. Brett et al. (2018) publish precise thallium isotopic compositions for sixteen geological RMs from different providers such as the USGS, CRPG, NIST and others. High-precision cadmium isotope ratios for a series of standard solutions and geological RMs from various providers such as BAM, IGGE and others are reported by Li et al (2018).
For the accurate determination of nitrogen mass fractions and d 15 N of silicate rocks with a low nitrogen mass fraction of < 200 lg g -1 , a method using a high-temperature sealed-tube combustion technique coupled with a continuous-flow isotope-ratio mass spectrometer (CF-IRMS) was developed and used for the analysis of USGS BHVO-2 and BCR-2 (Feng et al. 2018).
There are few analytical data available for halogens, and only some RMs are well characterised for halogens. Recently, there have been studies to fill this gap (e.g., Marks et al. 2017). In 2018, there are two substantial publications providing data for halogens: Kendrick et al. (2018) publish data for F, Cl, Br and I in thirteen RMs mainly from the USGS, NIST and GSJ, whereas He et al. (2018) present Br and I values for fifty-three Chinese RMs.
In order to measure radionuclides in various materials such as environmental samples and food samples after the accident at the Fukushima nuclear power plant, the development of appropriate RMs became necessary. Miura et al. (2018) introduce two recently prepared and certified fish meat and bone ash RMs for anthropogenic nuclides and the results of an interlaboratory comparison.
Appendix S3 presents a list of the 100 most requested RMs within the GeoReM database in 2018 (Jochum et al. 2005). Figure 5 shows the number of requests for the thirty-one most searched for RMs in GeoReM. The most frequent searched RMs are the NIST SRM 6x series glasses and BHVO-2 and BCR-2 from the USGS. Seventeen of the most requested

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RMs are microanalytical RMs, which also confirm the increasing relevance of microanalytical techniques such as LA-ICP-MS and SIMS.