High current–density anodic electrodissolution in flow–injection systems for the determination of aluminium, copper and zinc in non–ferroalloys by flame atomic absorption spectrometry

摘要

An automatic procedure with a high current-density anodic electrodissolutionunit (HDAE) is proposed for the determination ofaluminium, copper and zinc in non-ferroalloys by flame atomicabsorption spectrometry, based on the direct solid analysis. Itconsists of solenoid valve-based commutation in a flow-injectionsystem for on-line sample electro-dissolution and calibration withone multi-element standard, an electrolytic cell equipped with twoelectrodes (a silver needle acts as cathode, and sample as anode),and an intelligent unit. The latter is assembled in a PC-compatiblemicrocomputer for instrument control, and for dataacquisition and processing. General management of the process isachieved by use of software written in Pascal. Electrolytecompositions, flow rates, commutation times, applied current andelectrolysis time were investigated. A 0.5 mol l-1 HN03 solutionwas elected as electrolyte and 300 A/cm2 as the continuous currentpulse.