| The hydride/vapor generation is well-established sample introduction technique in atomic spectrometry when low detection limits are desired. Although the chemical hydride generation technique, which is sample introduction method based on the reaction of sodium tetrahydroborate with the acidic material that has many advantages and is widely used, there are some disadvantages, such as the usage of expensive reagent of sodium tetrahydroborate and its aqueous solutions must be prepared daily because of its unstablility. What's more, on account of the powerful reducibility of sodium/kalium tetrahydroborate, interferences from concomitant species can be severe. The electrochemical hydride/vapor generation (EC-HG/EC-VG) methods have been developed as alternatives to the chemical methods.Considering the fact that the analytical performances of the EC-HG and ECVG were directly related to the cathode material and the design of the electrolytic cell, efforts were made in this work to develop suitable cathode material for EC-HG or ECVG determination. Besides, systematic researchs, which based on previous work and quantitative data in this work, were also carried out on the mechanism of electrochemical hydride/vapor generation. The details are listed as follows:A three-dimensional reticular W filament electrode was used as the cathode in the EC-HG system. At low temperatures, the TeH2 generated on the reticular W filament cathode surface could be effectively driven out by sweeping gas in the cathode chamber and was determined by atomic fluorescence spectrometry (AFS). A simple and highly accurate method was developed for the detection of Te in soldering tin material by coupling EC-HG with AFS.Considering the excellent characteristics of polyaniline (PANI) material, such as unique stablility and avoids the use of organic solvents, we experimented its performances by Linear sweep voltammetry and found that the PANI film improved the reduction of Hg(Ⅱ), allowing the reduction of Hg(II) at higher potentials. In this work, we developed an ECVG-AFS system with PANI/graphite as cathode for Hg (Ⅱ) determination. Owing to the fact that a catalytic process may be involved in the reduction process, this proposed method had the virtues of higher sensitivity, excellent stability and lower memory effect. This developed method was successfully applied for analyzing trace amounts of mercury in biological samples. In the present work, PANI on Pb electrode was synthesized electrochemically and this PANI/Pb electrode was used as cathode material in the EC-HG-AFS system for the determination of tin. Attributing to the superior reduction activity of the PANI film for Sn (IV), this proposed method had the virtues of higher sensitivity, excellent stability and lower memory effect. This developed method was successfully applied for analyzing total tin in foods.An integrated EC-HG cell was laboratory constructed and a small dimension (180μl) graphite tube used as cathode chamber. This integrated cell was free of ion-exchange membrane and individual anolyte. The non-membrane setup enabled the electrolyte stream to be sequentially pumped through cathode chamber, gas liquid separator (GLS) chamber and anode chamber acted as both catholyte and anolyte. Therefore, it had advantages of low-cost and environmental-friendly. In addition, the screw cap makeup for components seal makes assembling of EC-HG cell be easy, and reduced the time required for cathode replacement or cleaning. A simple and sensitive flow injection method for the detection of As was created by coupling this integrated EC-HG cell with AFS, and this developed method was successfully applied to determine trace amounts of As in biological samples.
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