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All-solid-state sensors with polyvinyl chloride (PVC)-based membranes using off-the-shelf N-hydroxysuccinimide (NHS) and succinimide (Succ) ionophores were prepared using DOP (dioctyl phthalate) and NPOE (ortho-nitrophenyloctyl ether) as plasticizers. Good responses were obtained when NHS was used. The potentiometric response of the proposed electrode is independent of pH over the range 2–6. The electrode shows a fast response time of 0.25 s. The electrode exhibits a Super-Nernstian response, with 37.5 mV/decade, with a potentiometric detection limit of 4.4 μM. The proposed sensor revealed good selectivity towards a group of transition metal ions.

This work describes the use of an array of potentiometric sensors and an artificial neural network response model to determine perchlorate and sulfide ions in polluted waters, by what is known as an electronic tongue. Sensors used have been all-solid-state PVC membrane selective electrodes, where their ionophores were different metal-phtalocyanine complexes with specific and anion generic responses. The study case illustrates the potential use of electronic tongues in the quantification of mixtures when interfering effects need to be counterbalanced: relative errors in determination of individual ions can be decreased typically from 25% to less than 5%, if compared to the use of a single proposed ion-selective electrode.

A sensor array of 9 potentiometric PVC sensors has been employed for the simultaneous determination of heavy metals in soil. Sensors were firstly characterized in their response: Nernstian behavior, a concentration range from ca. 10−6 to 10−2 M and selectivity coefficients confirming that all sensors had cross‐response for the target ions. The mixed response system was modeled employing Artificial Neural Networks. The proposed tool was applied to the determination of Pb2+, Cd2+, Cu2+ and Zn2+ in soils at the mg kg−1 level with satisfactory performance. Results were compared and validated against AAS reference methodology, with correlations R2>0.948 for the four heavy metals considered.

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An automatic titration method is reported to resolve ternary mixtures of transition metals (Pb 2+ , Cd 2+ and Cu 2+ ) employing electronic tongue detection and a reduced number of pre-defined additions of EDTA titrant. Sensors used were PVC membrane selective electrodes with generic response to heavy-metals, plus an artificial neural network response model. Detection limits obtained were ca. 1 mg·L -1 for the three target ions and reproducibilities 3.0% for Pb 2+ , 4.1% for Cd 2+ and 5.2% for Cu 2+ . The system was applied to contaminated soil samples and high accuracy was obtained for the determination of Pb 2+ . In the determination Cd 2+ and Cu 2+ , sample matrix showed a significant effect.

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