Voltammetric determination of heavy metals in microvolumes of rain water

Analytical methods for the trace determination of heavy metals in microvolu mes of real water samples by using shipping voltammetry at microelectrodes and microelectrode arrays were investigated. Voltammetric procedures at gol d platinum and glassy carbon microelectrodes including appropriate measurin g cells were developed and validated by the application of electrothermal v aporization-inductively coupled plasma-mass spectrometry (ETV-ICP-MS) as we ll as stripping voltammetry performed at conventionally sized mercury elect rodes. The influence of a piezo actuator on the accumulation efficiency of the analyte at the electrode surface was tested. Detection limits in the lo w picogram range were achieved with anodic stripping voltammetry and Ostery oung-square-wave or differential pulse detection. The methods were applied to the determination of Pb, Cd, Zn, and Cu in single raindrops and small vo lumes of rain water.