Chemical separation automated

Chemical separation techniques can be used to reduce spectral interferences and concentrate the analyte. These techniques include solvent extraction(39) and hydride generation(39, 46, 47). At Imperial College, the hydride generation technique is being used on a daily basis(46) for the analysis of soils, sediments, waters, herbage, and animal tissue. The solvent extraction technique is ideally suited for automated systems where the increased manipulation is carried out automatically, and a labor intensive step and sources of contamination are avoided. 

The early chemical separations with the heaviest elements were performed manually. Today, most of the research has turned to automated chemical separation techniques. 

As chemical investigations progress from Z= 104-105 (with detection rates of atoms per hour), through Z= 106-108 (with detection rates of atoms per week), and on to even heavier elements (with expected detection rates of only a few atoms per month), manually performed chemical separations become impractical. With the automated liquid-phase chemical separation systems that have been developed to date, faster chemical separation and sample preparation times have been achieved. In addition, the precision and reproducibility of the chemical separations has been improved over that obtainable via manually performed separations. 

This robotic sample preparation and counting technology, together with mechanical improvements in the chemical separation system, has resulted in an automated column chromatography system that can run almost autonomously, whereas several people were required to operate the ARCA II system for a transactinide chemistry experiment. 

All phases of analytical development are ideally supported by chemical separation techniques such as HPLC, TLC, GC, SFC, and CE. HPLC continues to be the primary method of analysis throughout the pharmaceutical development process. Although HPLC is limited in its ability to separate more than 15-20 components in a single analysis, and variations in columns and instrumentation manufacturer to manufacturer complicate transfer of methods, HPLC can readily be implemented to meet ICH requirements for method performance. For early-phase methods, HPLC can be coupled dynamically to mass and nuclear magnetic resonance spectrometers to facilitate the identification of unknown impurities. In later phases, HPLC can be implemented in a fully automated format as a high-throughput method for release and stability testing. 

Neutron activation analysis has proven to be a convenient way of performing the chemical analysis of archaeologically-excavated artifacts and materials. It is fast and does not require tedious laboratory operations. It is multielement, sensitive, and if need be, can be made entirely non-destructive. Neutron activation analysis in its instrumental form, i.e. that involving no chemical separation, is ideally suited to automation and conveniently takes the first step in data flow patterns that are appropriate for many taxonomic and statistical operations. 

Md produced in the Am( C,3n) reaction was identified by using the Automated Chromatographic Chemical Element Separator System, ACCESS, in which ammonium a-hydroxy isobutyrate (a-HIB) was used for the separation of Md (Kadkhodayan et al. 1992). The other rapid chemical separation apparatus is described in the reviews (Herrmann and Trautmann 1982 Trautmann 1995) and also in Chap. 20 of this Volume. 

Repetition Since the moment in time at which a single transactinide atom is synthesized can currently not be determined and chemical procedures often work discontinuously, the chemical separation has to be repeated with a high repetition rate. Thus, thousands of experiments have to be performed. This inevitably led to the construction of highly automated chemistry set-ups. Due to the fact, that the studied transactinide elements as well as the interfering contaminants are radioactive and decay with a certain half-life, also continuously operating chromatography systems were developed. 

Future Techniques for Automated Liquid-Phase Chemical Separations... 

Abstract An overview over the chemical separation and characterization experiments of the four transactinide elements so far studied in liquid phases, rutherfordium (Rf), dubnium (Db), seaborgium (Sg), and hassium (Hs), is presented. Results are discussed in view of the position of these elements in the Periodic Table and of their relation to theoretical predictions. Short introductions on experimental techniques in liquid-phase chemistry, specifically automated rapid chemical separation systems, are also given. Studies of nuclear properties of transactinide nuclei by chemical isolation will be mentioned. Some perspectives for further liquid-phase chemistry on heavier elements are briefly discussed. 

Chapter 5 shows the progress made in experimental techniques including automated devices for chemical separations performed in the aqueous phase and the gas-phase as well as coupling of such devices to recoil separators. 

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