Ratiometric Fluorescent Paper‐Based Sensor Based on CdTe Quantum Dots and Graphite Carbon Nitride Hybrid for Visual and Rapid Determination of Cu²⁺ in Drinks

Abstract

A simple and effective ratiometric fluorescence sensor of CdTe QDs/GCNNs for on‐site and rapid analysis of Cu2+ has been established by mixing physically CdTe QDs and graphite carbon nitride (GCNNs). Two emissions peaks of CdTe QDs at 572 nm and GCNNs at 436 nm are both excitated at 340 nm. Under a UV lamp, fluorescent of traffic yellow CdTe QDs is linearly quenched by Cu2+ (as the detection signal), while blue GCNNs remains unchanged (as the reference), resulting in a distinguishable color change gradually from pink yellow to blue. The limit of detection (LOD) of this new sensor for Cu2+ is as low as 0.47 ng mL−1 with 1.4 % RSD. The established method has been successfully applied to detection of Cu2+ in various drinks with satisfactory results. Moreover, a paper‐based sensor, which has been prepared by soaking cellulose acetate membrane in CdTe QDs/GCNNs sensor solution, has a wide semiquantitative detection range for Cu2+ (0.01 ~ 5.0 μg mL−1). It has realized successfully on‐site and rapid determination of Cu2+ in red wine without any pretreatment procedure and is of great promotion and application value in determination of Cu2+ in liquid samples.

Paper-Based Electrical Sensors for Aqueous Heavy Metal Ion Detections

“…The authors of a recent study have developed a ratiometric fluorescence sensor method for the on-site and rapid determination of Cu2+ in drinks. 61 The method is based on the mixture of CdTe QDs and GCNNs, and has been shown to be more precise and accurate, as well as cheaper, simpler, more selective, and sensitive, than other published reports.…”

Semiconductor/Carbon Quantum Dot‐based Hue Recognition Strategy for Point of Need Testing: A Review

“…It was used for on‐site visual semi‐quantitative assay of Cu 2+ ions in red wine examples by hue recognition. [21] Wu also prepared a MOF/CdTe QDs‐based test paper for visual determination of Cu 2+ and Hg 2+ ions. [22a] Although the sensitivity and selectivity of these two test papers were not so good as other studies, on‐site and rapid determination of targets in red wine without any pretreatment procedure was realized successfully.…”

“…Wu and colleagues prepared a paper‐based sensor through drenching cellulose acetate membrane in probe solution. It was used for on‐site visual semi‐quantitative assay of Cu 2+ ions in red wine examples by hue recognition [21] . Wu also prepared a MOF/CdTe QDs‐based test paper for visual determination of Cu 2+ and Hg 2+ ions [22a] .…”

Recent advances in cellulose-based membranes for their sensing applications

“…CdTe quantum dots (CdTe QDs) can be worked as the sensing platform for metal ions detection (Elmizadeh et al 2017 ). Wu Yiwei and co-workers synthesized a ratiometric fluorescent cellulose acetate membrane, which was immersed in CdTe QDs/graphite carbon nitride (GCNNs) solutions (He et al 2020 ). With the increase of Cu 2+ concentrations, the color of this membrane sensor was gradually changed from pink yellow to blue under UV lamp.…”