Booming atomic spectrometry in China

With the fast growing economy and industrialization, analytical atomic spectrometry research has been undergoing rapid development in China. In 2014, there were 115 manuscripts submitted from China to Journal of Analytical Atomic Spectrometry (JAAS), nearly a quarter of the total number of submissions received by the journal, making submissions from China by far the most prolific out of the 44 countries that submitted. China today is making serious contributions to chemistry in general and analytical atomic spectrometry in particular.

Atomic spectrometry research in China started in the 1950's, pioneered by Benli Huang et al. However, it remained stagnant due to the Culture Revolution in the 60's and 70's. After the country's opening policy was established, atomic spectrometry became one of the most active research areas due to the generation of great atomic spectrometrists in the 80's and 90's, including Benli Huang, Zhaolun Fang, Zheming Ni, Qinhan Jin, Zhanxia Zhang, Xiaowei Guo, Zhucheng Jiang, Xiaoru Wang, Pengyuan Yang, Gongshu Zhang, Mingzhong Liu, Zhuoyong Zhang, and Xianjin Zeng. In recent years, with the endeavor of Chinese atomic spectrometrists and the return of many Chinese scholars from overseas, the general research capability of Chinese scientists has risen to a new level. Guibin Jiang's group have made great contributions to the hyphenated techniques, especially for speciation analysis using chromatographic separation coupled with atomic spectrometric detection. They developed a series of methods based on AFS detection coupled with GC or HPLC for speciation analysis. Their distinguished work has made contributions to the development of hyphenated techniques and speciation analysis in China. Zhifang Chai's group has been very active in using SRXRF in the study of toxicological effects of heavy metals and nanomaterials in living systems. To evaluate the toxicological effects of exposure to rare earth elements, nondestructive and multi-elemental microbeam SRXRF (mXRXRF) was used to map the alteration of many elements. In recent years, they applied mXRXRF to the study of transportation and toxicological effects of nanomaterials in animal models. Metalloproteins have been further studied by conventional separation methods combined with SRXRF. The results have provided important data for metabolic studies. Shan Gao and Shenghong Hu's groups have also done excellent work including reporting many unique applications of laser ablation-based analytical atomic spectrometry techniques in geosciences. Many highly cited research papers have been published by these groups.

Xinrong Zhang's group reported pioneering work using an ICP-MS based immunoassay for protein quantitative determination by using rare earth elements as an elemental label linked to an antibody. The method's sensitivity was enhanced by using gold nanoparticle tags instead of lanthanide ions. They also used laser ablation to introduce multi-elemental tags of antibodies immobilized on a microarray to ICP-MS directly. They further proposed a highly sensitive immunoassay based on single-particle mode detection by ICP-MS in a time-resolved analysis mode. Currently, the same strategy is being used for fast DNA sequencing. Xinrong Zhang has paved the way for ICP-MS based immunoassays and is still bringing milestones in the development of this area.

Qiuquan Wang's group developed element-coded affinity tag strategies for peptide/protein screening and quantification, in which native and foreign element-tags have been investigated. Quantified peptides and/or proteins in biological samples can be obtained by determining tagged elements using HPLC-AFS and HPLC-ICP-MS. Jianhua Wang's group has been dedicated to the study of miniaturized separation and preconcentration protocols for trace metal species with the so-called meso-fluidic lab-on-valve system, followed by graphite furnace AAS and AFS detection, which not only provides a more flexible approach for flow manifold design but also opens a promising avenue for the miniaturization of analytical instrumentation. They have recently exploited the potential applications of live cells in the separation and speciation of metal species. Xiandeng Hou's group covers a wide variety of atomic spectrometry. Instead of chromatographic separation, they achieved simple speciation analysis using photo chemical vapour generation method. They further explored the surface chemistry of nanoparticles for automated elemental speciation analysis. Tungsten-coil electrothermal vaporization was used to expand the detectable element range for traditional hydride generation-AFS instruments, and the same device could be used to introduce samples into flame furnace AAS. This group is also quite active in atomic spectrometry instrument development and constructed the FF-AAS atomizer and enhanced the performance of FF-AAS by using cloud point extraction and precipitation-dissolution in a knotted reactor as the preconcentration methods. By using a tungsten-coil atomizer and/or a hand held CCD detector, a portable electrothermal AAS instrument was constructed. Bin Hu's group made great contributions to electrothermal vaporization for sample introduction into ICP-OES and ICP-MS. They also explored various advanced materials as solid-phase extraction materials, and established novel analytical methods based on flow injection on-line/off-line micro-column separation/preconcentration ICP-OES/MS for trace element analysis or speciation analysis. Wei Hang's group developed a buffer-gas-assisted laser ablation and ionization orthogonal TOFMS. With this configuration, the problems of ion energy dispersion and the interference of multi-charged ions could be effectively solved. Its application in standardless semi-quantitative analysis of solid samples was further explored. Laser ionization mass spectrometry has the fascinating potential to be applicable to the simultaneous determination of elements in various solid samples, elemental speciation analysis, depth profiling and elemental imaging.

Other than the lab-developed instruments, almost all types of atomic spectrometry instruments have been gradually manufactured in China. More and more organizations in China can now afford expensive instruments for their research due to the booming economy and steadily growing funding for fundamental research from the Chinese government. It is roughly estimated that 400 ICP-MS instruments have been sold per year in the last couple years. Domestic academic meetings specifically for atomic spectrometry have also been held frequently. The 3^rd National Atomic Spectrometry Conference was held in Gulin in September 14^th–16^th, 2014, in which 265 conferees were present. The 9^th National Atomic Spectrometry Salon was held in Suzhou on October 31^st, 2014, which had nearly 100 attendees. Many international analytical chemistry conferences have also been held in China, which have atomic spectrometry sessions.

With the unanimous support from the Editorial Board of JAAS, we have devoted a themed issue to atomic spectrometrists in China, in view of the growing contributions from Chinese scientists to analytical atomic spectrometry. This special issue aims to introduce Chinese world-class research in atomic spectrometry, and to promote scientific exchange in analytical chemistry research between China and other regions of the world.

The papers in this themed issue will provide readers with a glimpse of the wide scope of the research currently being conducted by atomic spectrometrists in China. There are 1 Perspective, 16 Papers and 2 Technical Note articles involved in this special issue, which were contributed by 19 groups of analytical chemists from 12 universities and research institutes. Various research areas in atomic spectrometry are represented. The diverse research interests span from sample introduction, separation/preconcentration, speciation analysis, atomization/excitation, instrumentation, hyphenated techniques, and novel applications of analytical atomic spectrometry especially in biological and environmental studies.

JAAS would like to express sincere thanks to all the colleagues in China for their contributions to this themed issue, as well as the expert reviewers for their contributions.

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