Construction of a New Flow‐through Cell for Screen Printed Electrodes

In this paper a new flow‐through cell for voltammetric determinations using screen printed electrodes is described. This cell is much simpler than one with similar performances described in a previous work. This new flow‐through cell has been coupled to a multisyringe flow injection system (MSFIA) and to a multiport selection valve allowing the online calibration using the standard addition method. The uses of the MSFIA, together with the small volume of the flow cell and the reduced surface area of the solid phase electrode (SPE) have considerably reduced the volume of reagents and samples to be used. This system has allowed obtaining similar or better detection limits than those obtained using other techniques and flow analysis devices such as SIA, FIA, LOV and microfluidic channels. Graphite ink has been used for the development of screen‐printed electrodes. The determination of Cd and Pb with ASV has been made through its co‐deposition with Bi. For this, Bi(III) solution and the sample were mixed in line. Due to the creation of a new Bi film in each voltammetric cycle, very well defined and reproducible peaks corresponding to Cd and Pb have been obtained. The use of Bi is one of the most important advantages of this system, since it is a recognized substitute for Hg, and its impact on the environment is much lower due to its reduced toxicity. The fact of being an automatic system, the low cost of its components, its simplicity and ease of handling, make it a system that could be useful for monitoring tasks in fieldwork, or measurements on board.