Determination of Labile Cadmium Using a Screen‐Printed Electrode Modified by a Microwell

A microwell has been deposited on the working surface of a screen‐printed electrode in order to reduce the sample volume from 10 mL to 200 μL for trace metal analysis in square wave anodic stripping voltammetry. It has been shown that the sample volume reduction did not affect the sensitivity. A detection limit of 2×10−9 mol L−1 of Cd was established with these modified sensors for a preconcentration time of 60 s without stirring. Also it has been shown that pH ranging from 4 to 7 did not affect the sensor sensitivity. These modified sensors were able to run at neutral pH in real samples, such as soil solutions, containing higher organic carbon concentration and thus offered a first and rapid approach of Cd speciation.