A lab-on-a-tip approach to make electroanalysis user-friendly and de-centralized: Detection of copper ions in river water

The development of portable and user-friendly sensing platforms is a hot topic in the field of analytical chemistry. Among others, electroanalytical approaches exhibit a high amenability for reaching this purpose, i.e. the commercial strips for diabetes care are an obvious success. However, providing fully-integrated and user-friendly methods is the leitmotiv. In this work we evaluate the use of a disposable pipette tip, opportunely configured, to realize the first example of lab-on-a-tip. The combination of a pipette tip, wire electrodes, and cotton wool filter, highlights the suitability of producing a novel one-shot electroanalytical platform that does not require expertise-required tasks. To demonstrate the feasibility of this novel method, copper (Cu2+) is detected in water samples by means of anodic stripping voltammetry. The quantification is performed directly into the tip that contains a cotton wool filter: the filter has the double function of purifying the matrices from gross impurities and releasing all the pre-loaded reagents necessary for the assay. After optimizing the experimental parameters, the lab-on-a-tip was capable of detecting Cu2+ linearly up to 300 μg/L with a detection limit of 6.3 μg/L. The effectiveness of the platform was confirmed by testing 50, 100, and 150 ppb Cu-spiked river water sample with recovery value comprised between 92 and 103%.