Surface and subsurface examination of graphite tubes after electrodeposition of noble metals for electrothermal atomic absorption spectrometry

Electrochemical Modification of a Graphite Platform for a Solid Sampling Electrothermal Atomic Absorption Spectrometry of Mercury

“…Similarly, the sensitivity and the precision of determination are the same. As the advantage of an electrochemical coating, the penetration and transportation of noble metals into the subsurface domain of the graphite are mentioned, 22 but the stability of the surfaces and the lifetime of both coatings were the same. This process of electrochemical coating of the SS platform surface is promising for the preparation of modifiers, and also for the another purpose, e.g.…”

“…Penetration is more pronounced using electrodeposition, since this forces the transportation of noble metals into the subsurface domain of the graphite. [21][22][23] The goal of this work was to utilize the advantages of an electrochemical modification of a graphite surface for mercury determination in environmental materials, such as soils, sediments and plant by using SS-ETAAS. Electrochemical procedures in cells and in drops for modifying the solid sampling (SS) platform surface were investigated and optimized.…”

Investigation of aging processes of graphite tubes modified with iridium and rhodium used for atomic spectrometry

“…When electrothermal atomization is applied, special attention is always placed on the use of modifiers, especially noble metals that, since their introduction, are undoubtedly the most often employed [6]. In fact, much work has been done towards the application of noble metals modifiers for various analytes and matrices [7,8], and towards understanding the mechanisms of the analyte-modifier and substrate-analyte-modifier interactions [9][10][11][12]. An expected advantage of the modifier is improved long-term performance, and it was justified that noble metals modifiers could be used for this purpose [13][14][15].…”

“…It was found that electrodeposition of noble metals on the graphite surface offers significantly improved performance in the presence of a corrosive matrix [16,17]. According to the current understanding of the mechanism of the interaction between noble metals and graphite, they stabilize the analyte and act as permanent modifiers via the formation of intercalation compounds in the subsurface layer of pyrographite [9,10,18,19]. Penetration of noble metals within the pyrographite domain is expected to occur immediately after injection of the modifier solution, at the sampling/drying stage, due to the porosity of the pyrographite and nanometer scale cracks on the virgin pyrographite surface.…”

Performance of permanent iridium modifier in the presence of corrosive matrix in graphite furnace atomic absorption spectrometry

“…Noble metals (Pd, Ir, or Rh) electrodeposited on the graphite penetrate below the surface where they are intercalated and remain near the surface during the lifetime of the tube [12]. Therefore, the aim of this work was to investigate the analytical performance of electrodeposited iridium alone or in combination with palladium for the determination of cadmium in strongly interfering acid solution containing chlorides.…”