An automatic procedure with a high current-density anodic electrodissolution
unit (HDAE) is proposed for the determination of
aluminium, copper and zinc in non-ferroalloys by flame atomic
absorption spectrometry, based on the direct solid analysis. It
consists of solenoid valve-based commutation in a flow-injection
system for on-line sample electro-dissolution and calibration with
one multi-element standard, an electrolytic cell equipped with two
electrodes (a silver needle acts as cathode, and sample as anode),
and an intelligent unit. The latter is assembled in a PC-compatible
microcomputer for instrument control, and for data
acquisition and processing. General management of the process is
achieved by use of software written in Pascal. Electrolyte
compositions, flow rates, commutation times, applied current and
electrolysis time were investigated. A 0.5 mol l-1 HN03 solution
was elected as electrolyte and 300 A/cm2 as the continuous current
pulse.
The performance of the proposed system was evaluated by
analysing aluminium in Al-alloy samples, and copper/zinc in brass
and bronze samples, respectively. The system handles about 50
samples per hour. Results are precise (R.S.D. < 2%) and in
agreement with those obtained by ICP-AES and spectrophotometry
at a 95% confidence level.