Miniaturization in voltammetry: ultratrace element analysis and speciation with twenty-fold sample size reduction

Area of Science:

• Analytical Chemistry
• Environmental Science
• Electrochemistry

Background:

• Voltammetric techniques are crucial for trace and ultratrace elemental analysis.
• Current methods require large sample volumes (e.g., 10 mL), limiting applications and precision.
• A need exists for reduced sample volume methods in elemental determination and speciation.

Purpose of the Study:

• To develop a method for trace and ultratrace elemental determination and speciation using significantly reduced sample volumes.
• To introduce a novel sample holder for conventional voltammetric instrumentation.
• To achieve a 20-fold reduction in sample size for ultratrace detection.

Main Methods:

• Development and implementation of a new sample holder for voltammetric analysis.
• Determination of trace/ultratrace elements (Cd, Co, Cu, Ni, Pb) in rainwater.
• Copper speciation in seawater using competitive ligand equilibration-cathodic stripping voltammetry (CLE-CSV).

Main Results:

• Achieved a 20-fold reduction in sample volume, down to 0.5 mL for ultratrace detection.
• Successfully determined trace elements in rainwater and copper in seawater.
• Demonstrated consistent copper speciation in seawater via CLE-CSV.
• Reported a 2.5-fold decrease in analysis time and a 20-fold reduction in reagent consumption.
• Maintained similar detection capabilities, precision, and accuracy compared to conventional methods.

Conclusions:

• The novel sample holder enables highly sensitive elemental analysis with minimal sample volume.
• This technique is applicable to limited sample availability (e.g., porewaters, snow, biological samples).
• The method facilitates high-resolution temporal trend analysis in environmental monitoring.