Voltammetric techniques have emerged as powerful methods for the determination and speciation of
trace and ultratrace elements without any preconcentration in several research fields. Nevertheless,
large sample volumes are typically required (10 mL), which strongly limits their application and/or the
precision of the results. In this work, we report a 20-fold reduction in sample size for trace and ultratrace
elemental determination and speciation by conventional voltammetric instrumentation, introducing the
lowest amount of sample (0.5 mL) in which ultratrace detection has been performed up to now. This goal
was achieved by a careful design of a new sample holder. Reliable, validated results were obtained for
the determination of trace/ultratrace elements in rainwater (Cd, Co, Cu, Ni, Pb) and seawater (Cu).
Moreover, copper speciation in seawater samples was consistently determined by competitive ligand
equilibration–cathodic stripping voltammetry (CLE–CSV). The proposed apparatus showed several
advantages: (1) 20-fold reduction in sample volume (the sample size is lowered from 120 to 6 mL for
the CLE–CSV procedure); (2) decrease in analysis time due to the reduction in purging time up to
2.5 fold; (3) 20-fold drop in reagent consumption. Moreover, the analytical performances were not
affected: similar detection capabilities, precision and accuracy were obtained. Application to sample of
limited availability (e.g. porewaters, snow, rainwater, open ocean water, biological samples) and to the
description of high resolution temporal trends may be easily foreseen.
Voltammetric techniques have emerged as powerful methods for the determination and speciation of
trace and ultratrace elements without any preconcentration in several research fields. Nevertheless,
large sample volumes are typically required (10 mL), which strongly limits their application and/or the
precision of the results. In this work, we report a 20-fold reduction in sample size for trace and ultratrace
elemental determination and speciation by conventional voltammetric instrumentation, introducing the
lowest amount of sample (0.5 mL) in which ultratrace detection has been performed up to now. This goal
was achieved by a careful design of a new sample holder. Reliable, validated results were obtained for
the determination of trace/ultratrace elements in rainwater (Cd, Co, Cu, Ni, Pb) and seawater (Cu).
Moreover, copper speciation in seawater samples was consistently determined by competitive ligand
equilibration–cathodic stripping voltammetry (CLE–CSV). The proposed apparatus showed several
advantages: (1) 20-fold reduction in sample volume (the sample size is lowered from 120 to 6 mL for
the CLE–CSV procedure); (2) decrease in analysis time due to the reduction in purging time up to
2.5 fold; (3) 20-fold drop in reagent consumption. Moreover, the analytical performances were not
affected: similar detection capabilities, precision and accuracy were obtained. Application to sample of
limited availability (e.g. porewaters, snow, rainwater, open ocean water, biological samples) and to the
description of high resolution temporal trends may be easily foreseen.
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