A pH‐Based Single‐Sensor Array for Discriminating Metal Ions in Water

Abstract

Human activities, such as mining and manufacturing, expose society and the natural environment to harmful levels of metal ions. Recently, optical sensor arrays for metal ion detection have become popular owing to their favourable features, such as facile sample preparation and the requirement of less expensive instrumentation compared to traditional, spectrometry‐based analysis techniques. Sensor arrays usually consist of numerous optical probes that are used in combination to generate unique analyte responses. In contrast, here we present an array that comprises a single fluorescent sensor, Coum4‐DPA, that produces unique responses to metal ions in different pH environments. With this simple sensing platform, we were able to classify 10 metal ions in different water sources and quantify Pb2+ in tap water using just one fluorescent sensor, a few pH buffers and two sets of spectral data. This novel approach significantly decreases time and costs associated with probe synthesis and data collection, making it highly transferrable to real‐world metal sensing applications.

Optical Sensor Arrays for the Detection of Neurotransmitters

“…[67] Following the similar strategy, New's group reported 7-hydroxy-4-methylcoumarin substituted with dipicolylamine moiety as a single-sensing element to discriminate among transition metal ions varying the pH. [68] A major challenge for the detection of analytes with the non-selective sensor is restricted by the intensive chemical synthesis and the associated cost of multiple sensing units required to generate a large number of data such that unique fingerprints for each analyte are obtained from the data set. To address the problem, photochromic receptors have been employed where the sensing element can generate two distinct outputs on photoisomerization.…”

“…A simplified yet fascinating natural fluorophore as the sensing element was reported from our group, where a single sensing element, curcumin, that can exist in two different forms on pH variation was demonstrated for discrimination among fourteen different lanthanide ions using machine learning techniques [67] . Following the similar strategy, New's group reported 7‐hydroxy‐4‐methylcoumarin substituted with dipicolylamine moiety as a single‐sensing element to discriminate among transition metal ions varying the pH [68] …”

One‐Component Artificial Gustatory System Based on Hydrogen‐Bond Organic Framework for Discrimination of Versatile Analytes

“…The concentration is lower or at least comparable to some of previous reports. [46,47] Furthermore, hierarchical cluster analysis (HCA) was carried out to classify multiple metals. The cluster tree yielded by HCA further confirmed that the sensor array could well distinguish 14 metal ions (Figure 2d).…”

Printed colorimetric chemosensor array on a 96-microwell paper substrate for metal ions in river water

“…Based on the inherent cross-reactivities of artificial receptors (Gardner, 1991), chemosensors in an array display a fingerprint-like response pattern according to the different types of analytes and their concentrations (Anzenbacher et al, 2010;Sasaki et al, 2021a). Therefore, qualitative and quantitative chemical information at the molecular level can be analyzed by data processing of the optical fingerprint-like response pattern (Huang et al, 2013;Sener et al, 2014;Xu et al, 2014;Hwang et al, 2015), allowing for accurate sensing, even in real samples (Palacios et al, 2008;Bowyer et al, 2022).…”