Characterization and mutual comparison of new electrolytic cell designs for hydride generation-atomic absorption spectrometry with a quartz tube atomizer using Se as a model analyte and Se-75 as a radioactive indicator
Abstrakt
Fifteen electrolytic flow-through cells belonging to three different design groups (non-membrane, thin-layer and tubular) have been constructed and characterized in this work. Atomic absorption spectrometry with a quartz tube atomizer has been employed as a detector and Se chosen as a model analyte.
At first optimization of relevant working parameters was performed and basic analytical characteristics were evaluated under the optimum experimental conditions for all cells. Mutual comparisons of the electrolytic cells were performed thereafter and 5 cells with best performance were selected for further evaluation.
Finally, a Se-75 radioactive indicator was employed to quantify the generation efficiency of selane as well as to visualize the spatial distribution of the analyte in the apparatus and track potential analyte losses. With respect to all relevant requirements the best performance was found for the thin-layer electrolytic cell (225 mm(3) cathode chamber volume) with efficiency of electrochemical hydride generation reaching 75% and a limit of detection (LOD) of 0.31 ng mL(-1) Se.
A generation efficiency of 78% and an LOD of 0.40 ng mL(-1) Se were obtained for the tubular cell (43 mm(3) cathode volume). High generation efficiency, fast response and low cathode chamber volume make the tubular cell an ideal candidate even for flow-injection and speciation analysis measurements.