Surface Modification of Gold by Quercetin Monolayer for the Electrochemical Determination of Copper(II)

A quercetin monolayer has been prepared on top of the self‐assembled 3‐mercaptopropionic acid (MPA) layer for the copper ion determination. Cu²⁺ ions are readily accumulated on this modified electrode through the complex formation and electrochemically detected. With a quercetin layer, the redox process of Cu²⁺ became more reversible than at the MPA‐modified electrode. Complexation sites in MPA and quercetin were occupied within five min when the electrode was immersed in 10 μM Cu²⁺ solution. The MPA and quercetin layers were stable enough to allow repeated EDTA treatment to remove adsorbed Cu²⁺ for the surface regeneration. Only 7% decrease was found after ten times regeneration and use. Linear current response was found over the concentration range of 1 nM and 10 μM with detection limit of 0.1 nM. Common interfering ions such as Cd²⁺, Zn²⁺, and Fe^2+/3+ did not show any electrochemical response in the potential range of Cu²⁺ determination.     

A New 3,5‐Bisporphyrinylpyridine Derivative as a Fluorescent Ratiometric Probe for Zinc Ions

A new 3,5‐disubstituted pyridine with two porphyrin moieties was prepared through an efficient synthetic approach involving 2‐formyl‐5,10,15,20‐tetraphenylporphyrin ( 1 ), piperidine, and catalytic amounts of [La(OTf)₃]. 3,5‐Bis(5,10,15,20‐tetraphenylporphyrin‐2‐ylmethyl)pyridine ( 2 ) was fully characterized and its sensing ability towards Zn²⁺, Cu²⁺, Hg²⁺, Cd²⁺, and Ag⁺ was evaluated in solution by absorption and fluorescence spectroscopy and in gas phase by using matrix‐assisted laser desorption/ionization (MALDI)‐TOF mass spectrometry. Strong changes in the ground and excited state were detected in the case of the soft metal ions Zn²⁺, Cd²⁺, Hg²⁺, and Cu²⁺. A three‐metal‐per‐ligand molar ratio was obtained in all cases and a significant ratiometric behavior was observed in the presence of Zn²⁺ with the appearance of a new band at 608 nm, which can be assigned to a metal‐to‐ligand charge transfer. The system was able to quantify 79 ppb of Zn²⁺ and the theoretical calculations are in accordance with the stoichiometry observed in solution. The gas‐phase sensorial ability of compound 2 towards all metal ions was confirmed by using MALDI‐TOF MS and in solid state by using polymeric films of polymethylmethacrylate (PMMA) doped with ligand 2 . The results showed that compound 2 can be analytically used to develop new colorimetric molecular devices that are able to discriminate between Hg²⁺ and Zn²⁺ in solid phase. The crystal structure of Zn^II complex of 3,5‐bisporphyrinylpyridine was unequivocally elucidated by using single‐crystal X‐ray diffraction studies.     

A reactive electrode (reactrode) for the voltammetric determination of heavy metals in laboratories and for use as a passive monitor in remote analysis

The use of a reactive electrode (reactrode) consisting of graphite, a solid ion exchanger (HYPHAN) and paraffin for the batch analysis of Cd²⁺, Cu²⁺, Pb²⁺ and Hg²⁺ in aqueous samples and as a passive monitor for these metal ions is described. The metal ions are accumulated on the reactrode surface at an open-circuit potential in an ion-exchange reaction. After the accumulation, the ion exchanger-bonded metal ions are reduced to the metals which remain on the electrode surface. In a following step, the metals are anodically dissolved which is recorded by differential-pulse voltammetry. The 3s detection limits for the analysis of drinking water are: 1.1×10^-7 mol/l for Pb²⁺, 5×10^-8 mol/l for Hg²⁺ and 2.4×10^-7 mol/l for Cu²⁺.The reactrode developed can be used for the passive monitoring of heavy metals in aqueous streams if the reactrode is mounted in a wall-jet cell which is part of a flow-through system. Using this arrangement, it has been possible to determine Hg²⁺, Cu²⁺ and Pb²⁺ in drinking water after 20 hours of accumulation.     

Rapid detection of trace Cu2+ using an l‐cysteine based interdigitated electrode sensor integrated with AC electrokinetic enrichment

Copper is an indispensable trace element for human health. Too much or too little intake of copper ion (Cu²⁺) can lead to its own adverse health conditions. Therefore, detection of Cu²⁺ is always of vital importance. In this work, a simple sensor was developed for rapid detection of trace Cu²⁺ in water, in which L‐cysteine (Cys) as a molecular probe was self‐assembled on a gold interdigital electrode to form a monolayer for specific capture of Cu²⁺. The interfacial capacitance of interdigital electrode was detected to indicate the target adsorption level under an AC signal working as the excitation to induce directed movement and enrichment of Cu²⁺ to the electrode surface. This sensor reached a limit of detection of 4.14 fM and a satisfactory selectivity against eight other ions (Zn²⁺, Hg²⁺, Pb²⁺, Cd²⁺, Mg²⁺, Fe²⁺, As³⁺, and As⁵⁺). Testing of spiked tap water was also performed, demonstrating the sensor's usability. This sensor as well as the detection method shows a great application potential in fields such as environmental monitoring and medical diagnosis.     

Competitive heavy metal removal by poly(2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid‐co‐itaconic acid)

The competitive removal of Pb²⁺, Cu²⁺, and Cd²⁺ ions from aqueous solutions by the copolymer of 2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid (AMPS) and itaconic acid (IA), P(AMPS‐co‐IA), was investigated. Homopolymer of AMPS (PAMPS) was also used to remove these ions from their aqueous solution. In the preparation of AMPS–IA copolymer, the molar percentages of AMPS and IA were 80 and 20, respectively. In order to observe the changes in the structures of polymers due to metal adsorption, FTIR spectra by attenuated total reflectancetechnique and scanning electron microscopy (SEM) pictures of the polymers were taken both before and after adsorption experiments. Total metal ion removal capacities of PAMPS and P(AMPS‐co‐IA) were 1.685 and 1.722 mmol Me²⁺/g_polymer, respectively. Experimental data were evaluated to determine the kinetic characteristics of the adsorption process. Competitive adsorption of Pb²⁺, Cu²⁺, and Cd²⁺ ions onto both PAMPS and P(AMPS‐co‐IA) was found to fit pseudo‐second‐order type kinetics. In addition, the removal orders in the competitive adsorption of these metal ions onto PAMPS and P(AMPS‐co‐IA) were found to be Cd²⁺ > Pb²⁺ > Cu²⁺ and Pb²⁺ > Cd²⁺ > Cu²⁺, respectively. Copyright © 2008 John Wiley & Sons, Ltd.     

Zn2+‐Regulated Self‐Sorting and Mixing of Phosphates and Carboxylates on the Surface of Functionalized Gold Nanoparticles

Herein, we describe the self‐sorting of phosphate‐ and carboxylate‐containing molecules on the surface of monolayer‐protected gold nanoparticles. Self‐sorting is driven by selective interactions between the phosphate probe and Zn²⁺ complexes in one monolayer; these interactions force the carboxylate probe to move to a second type of nanoparticle. This process effectively separates the probes and causes their localization in well‐defined spaces surrounding the nanoparticles. The removal/addition of Zn²⁺ metal ions from the system is used to convert the system from an ordered to a disordered state and vice versa. The possibility to control the location and transport of populations of molecules in a complex mixture creates new perspectives for the development of innovative complex catalytic systems that mimic nature.     

Influence of metal ions on the interaction between gatifloxacin and calf thymus DNA

To study the interaction between gatifloxacin (GT), metal ions (Cu²⁺, Cd²⁺, Co²⁺, Mg²⁺) and calf thymus DNA under condition of physiology pH, UV absorption and fluorescence methods were adopted. Result shows that metal ions and DNA are able to react with GT in ground state. In further research, by studying the influence of metal ions on binding of GT with DNA in metal ions–GT–DNA ternary system, we found that influential mechanism of Mg²⁺ on the binding of GT with DNA may be different from the other three. Mg²⁺ can act as a bridge in the binding of GT's carboxyl/carbonyl with DNA phosphate in certain concentration range; while Cu²⁺, Cd²⁺, Co²⁺ can combine directly with GT by reaction between GT carboxyl/carbonyl and DNA base, and enhance the binding ability of GT with DNA. The influence extent and type depend not only on the binding site of DNA with metal ions (phosphate or base), but also the binding ability of which. The stronger the binding ability of metal ions with DNA base is, the larger their promotion to binding of GT with DNA is. The order of metal ions’ influential ability on the binding of GT–DNA is identical to the binding ability order of metal ions with DNA base, that is: Cu²⁺ > Cd²⁺ > Co²⁺ > Mg²⁺.     

Catalytic effects of metal submonolayers formed by faradaic adsorption on the anodic oxidation of ascorbic acid at a platinum electrode

The catalytic effects of metal ions on the anodic oxidation of ascorbic acid on a Pt electrode in 1 M HClO₄ were studied by linear sweep voltammetry. The anodic peak due to a two-electron oxidation of ascorbic acid shifts to the negative potential side on the addition of Bi³⁺. This indicates the accelerating effect of Bi³⁺ on the oxidation of ascorbic acid. The presence of other metal ions, such as Pb²⁺, Hg²⁺, Tl⁺, Ag⁺ and Sb³⁺, also exerts similar effects. These metal ions were adsorbed on a Pt electrode at underpotentials and the adsorbed metals (denoted as M_ad) still remain on the electrode surface until the electrode potential goes up to and beyond the peak potential of the oxidation of ascorbic acid. On the other hand, metal ions forming no adsorbed layer on Pt, such as Co²⁺, Zn²⁺, Fe³⁺ and Ni²⁺, exhibit no catalytic effect. These facts suggest that the presence of a M_ad on Pt is essential for the promotion of the anodic oxidation of ascorbic acid. However, there is a difference in the catalytic action among the M_ad, for example, Cu_ad, Cd_ad, In_ad, Sn_ad and Mo_ad display no catalytic action.The catalytic activity depends on the degree of surface coverage by the M_ad. The maximal effect of the M_ad is attained in the submonolayer region. The effects of metal ions were discussed on the basis that the M_ad plays its major role in the removal of the adsorbed ascorbic acid occupying active sites on the electrode surface, and provides effective sites for the activation of adjacent water molecules. Furthermore, from the ¹³C NMR spectra for the oxidation products, the adsorbed water on the M_ad appears to function by promoting the subsequent hydration steps, following the electron-transfer step of ascorbic acid.     

Syntheses,structures of N‐(substituted)‐2‐aza‐[3]‐ferrocenophanes and their application as redox sensor for Cu2+ ion

Rigid N‐(substituted)‐2‐aza‐[3]‐ferrocenophanes L1 and L2 were easily synthesized from 1,1 ‐dicarboxyaldehydeferrocene and the corresponding amines. Ligands L1 and L2 were characterized by ¹H NMR, ¹³C NMR and single‐crystal X‐ray crystallography. The coordination abilities of L1 and L2 with metal ions such as Cu²⁺, Mg²⁺, Ni²⁺, Zn²⁺, Pb²⁺ and Cd²⁺ were evaluated by cyclic voltammetry. The electrochemical shift (ΔE_1/2) of 125 mV was observed in the presence of Cu²⁺ ion, while no significant shift of the Fc/Fc + couple was observed when Mg²⁺, Ni²⁺, Zn²⁺, Pb²⁺, Cd²⁺ metal ions were added to the solution of L1 in the mixture of MeOH and H₂O. Moreover, the extent of the anodic shift of redox potentials was approximately equal to that induced by Cu²⁺ alone when a mixture of Cu²⁺, Mg²⁺, Ni²⁺, Zn²⁺, Pb²⁺ and Cd²⁺ was added to a solution of L1. Ligand L1 was proved to selectively sense Cu²⁺ in the presence of large, excessive first‐row transition and late‐transition metal cations. The coordination model was proposed from the results of controlled experiments and quantum calculations. Copyright © 2012 John Wiley & Sons, Ltd.     

Heavy Metal Removal from Synthetic Solutions with Magnetic Beads Under Magnetic Field

The aim of this study is to prepare magnetic beads which can be used for the removal of heavy metal ions from synthetic solutions. Magnetic poly(ethylene glycol dimethacrylate‐vinyl imidazole) [m‐poly(EGDMA‐VIM)] beads were produced by suspension polymerization in the presence of magnetite Fe₃O₄ nano‐powder. The specific surface area of the m‐poly(EGDMA‐VIM) beads was found to be 63.1 m²/g with a size range of 150–200 µm in diameter and the swelling ratio was 85%. The average Fe₃O₄ content of the resulting m‐poly(EGDMA‐VIM) beads was 12.4%. The maximum binding capacities of the m‐poly(EGDMA‐VIM) beads were 32.4 mg/g for Cu²⁺, 45.8 mg/g for Zn²⁺, 84.2 mg/g for Cd²⁺and 134.5 mg/g for Pb²⁺. The affinity order on mass basis is Pb²⁺>Cd²⁺>Zn²⁺>Cu²⁺. Equilibrium data agreed well with the Langmuir model. pH significantly affected the binding capacity of the magnetic beads. Binding of heavy metal ions from synthetic wastewater was also studied. The binding capacities were 26.2 mg/g for Cu²⁺, 33.7 mg/g for Zn²⁺, 54.7 mg/g for Cd²⁺ and 108.4 mg/g for Pb²⁺. The magnetic beads could be regenerated up to about 97% by treating with 0.1 M HNO₃. These features make m‐poly(EGDMA‐VIM) beads a potential candidate for support of heavy metal removal under magnetic field.     

Novel Fe3O4/hydroxyapatite/β‐cyclodextrin nanocomposite adsorbent: Synthesis and application in heavy metal removal from aqueous solution

The increased global concern on environmental protection has made researchers focus their attention on new and more efficient methods of pollutant removal. In this research, novel nanocomposite adsorbents,i.e., magnetic hydroxyapatite (Fe₃O₄@HA) and magnetic hydroxyapatite β‐cyclodextrin (Fe₃O₄@HA‐CD) were synthesized and used for heavy metal removal. The adsorbents were characterized by FTIR, XRD, TGA, VSM, and SEM. In order to investigate the effect of β‐cyclodextrin (β‐CD) removal efficiency, adsorption results of nine metal ions were compared for both adsorbents. β‐CD showed the most increasing effect for Cd²⁺ and Cu²⁺ removal, so these two ions were selected for further studies. The effect of diverse parameters including pH, contact time, initial metal ion concentration and adsorbent dosage on the adsorption process was discussed. The optimum pH was 6 and adsorption equilibrium was achieved after 1 hr. Adsorption kinetic data were well fitted by pseudo‐second‐order model proposing that metal ions were adsorbed via chemical reaction. Adsorption isotherm was best described by the Langmuir model, and maximum adsorption capacity for Cd²⁺ and Cu²⁺ was 100.00 and 66.66 (mg/g), respectively. Desorption experiment was also done, and the most efficient eluent used for desorption of metal ions was EDTA (0.001 M) with 91% and 88% of Cd²⁺ and Cu²⁺ release, respectively. Recyclability studies also showed a 19% decrease in the adsorption capacity of the adsorbent after five cycles of regeneration. Therefore, the synthesized adsorbents were recognized as potential candidates for heavy metal adsorption applications.     

Simultaneous Determination of Cadmium,Lead, Copper and Mercury Ions Using Organofunctionalized SBA‐15 Nanostructured Silica Modified Graphite–Polyurethane Composite Electrode

A new sensor has been developed for the simultaneous detection of cadmium, lead, copper and mercury, using differential pulse and square wave anodic stripping voltammetry (DPASV and SWASV) at a graphite–polyurethane composite electrode with SBA‐15 silica organofunctionalized with 2‐benzothiazolethiol as bulk modifier. The heavy metal ions were preconcentrated on the surface of the modified electrode at ?1.1 V vs. SCE where they complex with 2‐benzothiazolethiol and are reduced to the metals, and are then reoxidized. Optimum SWASV conditions lead to nanomolar detection limits and simultaneous determination of Cd²⁺, Pb²⁺, Cu²⁺ and Hg²⁺ in natural waters was achieved.     

Uptake of Divalent Metal Ions (Cu2+, Zn2+ and Cd2+) by Polysiloxane Immobilized Glycinate Ligand System

ABSTRACT

Porous solid siloxane polymer carrying glycinate functional group of formula –(CH₂)₃NHCH₂COOH has been prepared by the sol-gel process. Treatment of aqueous solutions of divalent metal ions with the polysiloxane glycinate ligand system demonstrates that this material exhibits high potential for preconcentration of metal ions (Cu²⁺, Zn²⁺ and Cd²⁺). The ligand system chemisorbs these divalent metal ions, at optimum conditions, in the order: Cd²⁺ < Zn²⁺ < Cu²⁺. The uptake of copper ions is concentration dependent but it is independent on the presence of other competing ions. Treatment of the glycinate ligand system with acidic solution results in leaching of bound ligands. The highest leaching occurs in presence of copper ions at low pH     

Copper‐Doped CdSe/ZnS Quantum Dots: Controllable Photoactivated Copper(I) Cation Storage and Release Vectors for Catalysis

The first photoactivated doped quantum dot vector for metal‐ion release has been developed. A facile method for doping copper(I) cations within ZnS quantum dot shells was achieved through the use of metal‐dithiocarbamates, with Cu⁺ ions elucidated by X‐ray photoelectron spectroscopy. Photoexcitation of the quantum dots has been shown to release Cu⁺ ions, which was employed as an effective catalyst for the Huisgen [3+2] cycloaddition reaction. The relationship between the extent of doping, catalytic activity, and the fluorescence quenching was also explored.     

Preconcentration and Determination of Trace Amounts of Heavy Metals in Water Samples Using Membrane Disk and Flame Atomic Absorption Spectrometry

A fast and simple method for preconcentration of Ni^2＋, Cd^2＋, Pb^2＋, Zn^2＋, Cu^2＋ and Co^2＋ from natural water samples was developed. The metal ions were complexed with sodium diethyldithiocarbamate （Na-DDTC）, then adsorbed onto octadecyl silica membrane disk, recovered and determined by FAAS. Extraction efficiency, influence of sample volume and eluent flow rates, effects of pH, amount of Na-DDTC, nature and amount of eluent for elution of metal ions from membrane disk, break through volume and limit of detection have been evaluated. The effect of foreign ions on the percent recovery of heavy metal ions has also been studied. The limit of detection of the proposed method for Ni^2＋, Cd^2＋, Pb^2＋, Zn^2＋, Cu^2＋ and Co^2＋was found to be 2.03, 0.47, 3.13, 0.44, 1.24 and 2.05 ng·mL^-1, respectively. The proposed （DDTC） method has been successfully applied to the recovery and determination of heavy metal ions in different water samples.     

Simultaneous Determination of Lead,Copper, and Mercury Free from Macromolecule Contaminants by Square Wave Stripping Voltammetry

Abstract

A novel approach for the voltammetric determination of Pb²⁺, Cu²⁺, and Hg²⁺ in the presence of macromolecule contaminants was developed. An Au nanoparticles array was directly electrodeposited onto the gold electrode surface followed by a further modification of a mercaptoethanesulfonate (MES) monolayer. Square wave stripping voltammetry (SWSV) of Pb²⁺, Cu²⁺, and Hg²⁺ was performed on the doubly modified electrode. The electrodeposited gold nanoparticles provided a significantly improved sensitivity. Simultaneously, the MES monolayer efficiently prevented the macromolecules accessing the electrode surface. Compared with the bare gold electrode, the doubly modified electrode has the ability to detect metal ions in the presence of macromolecule contaminants, even when their concentration reach 100 ppm. Under the optimal conditions, the detection limits of 0.16, 0.15, and 0.14 ppb for Pb²⁺, Cu²⁺, and Hg²⁺ were obtained, respectively. The calibration graphs were linear in the concentration range of 1–100 ppb. The results of the analysis of a real metallurgy wastewater sample were reported. The electrode system has a great potential for the direct determination of trace metals in the complex environment and biological samples.     

Fabrication and application of a new modified electrochemical sensor using nano-silica and a newly synthesized Schiff base for simultaneous determination of Cd,Cu and Hg ions in water and some foodstuff samples

A new chemically modified carbon paste electrode was constructed and used for rapid, simple, accurate, selective and highly sensitive simultaneous determination of cadmium, copper and mercury using square wave anodic stripping voltammetry (SWASV). The carbon paste electrode was modified by N,N′-bis(3-(2-thenylidenimino)propyl)piperazine coated silica nanoparticles. Compared with carbon paste electrode, the stripping peak currents had a significant increase at the modified electrode. Under the optimized conditions (deposition potential, −1.100 V vs. Ag/AgCl; deposition time, 60 s; resting time, 10 s; SW frequency, 25 Hz; pulse amplitude, 0.15 V; dc voltage step height, 4.4 mV), the detection limit was 0.3, 0.1 and 0.05 ng mL⁻¹ for the determination of Cd²⁺, Cu²⁺ and Hg²⁺, respectively. The complexation reaction of the ligand with several metal cations in methanol was studied and the stability constants of the complexes were obtained. The effects of different cations and anions on the simultaneous determination of metal ions were studied and it was found that the electrode is highly selective for the simultaneous determination of Cd²⁺, Cu²⁺ and Hg²⁺. Furthermore, the present method was applied to the determination of Cd²⁺, Cu²⁺ and Hg²⁺ in water and some foodstuff samples.     

Reversible Self‐Assembly of Carboxylated Peptide‐Functionalized Gold Nanoparticles Driven by Metal‐Ion Coordination

Carboxylated peptide‐functionalized gold nanoparticles (peptide‐GNPs) self‐assemble into two‐ and three‐dimensional nanostructures in the presence of various heavy metal ions (i.e. Pb²⁺, Cd²⁺, Cu²⁺, and Zn²⁺) in aqueous solution. The assembly process is monitored by following the changes in the surface plasmon resonance (SPR) band of gold nanoparticles in a UV/Vis spectrophotometer, which shows the development of a new SPR band in the higher‐wavelength region. The extent of assembly is dependent on the amount of metal ions present in the medium and also the time of assembly. TEM analysis clearly shows formation of two‐ and three‐dimensional nanostructures. The assembly process is completely reversible by addition of alkaline ethylenediaminetetraacetic acid (EDTA) solution. The driving force for the assembly of peptide‐GNPs is mainly metal ion/carboxylate coordination. The color and spectral changes due to this assembly can be used for detection of these heavy‐metal ions in solution.     

Silver nanoparticle loaded on activated carbon and activated carbon modified with 2-(4-isopropylbenzylideneamino)thiophenol (IPBATP) as new sorbents for trace metal ions enrichment

The efficiencies and performances of silver nanoparticle loaded activated carbon modified with 2-(4-isopropylbenzylideneamino)thiophenol (IPBATP-Ag-NP-AC) and activated carbon modified with IPBATP (IPBATP-AC), as new sorbents, were evaluated for separation and preconcentration of Cu²⁺, Zn²⁺, Co²⁺, Cd²⁺ and Pb²⁺ ions from real environmental samples. The retained metals content was reversibly eluted using 5?mL of CH₃COOH (6.0?mol?L^?1) and/or 10?mL of 4.0?mol?L^?1 HNO₃ for IPBATP-Ag-NP-AC and IPBATP-AC, respectively. The experimental parameters influence the recoveries of metal ions including pH, amounts of ligand and supports, condition of eluents, sample and eluent flow rates of has been investigated. The preconcentration factors were found to be 100 for Zn²⁺, Cd²⁺, Co²⁺, Cu²⁺ and 50 for Pb²⁺ ions using IPBATP-Ag-NP-AC, and 50 for Zn²⁺, Cd²⁺, Co²⁺, Cu²⁺ and 25 for Pb²⁺ ions using IPBATP-AC. The detection limit of both SPE-based sorbents was between 1.6–2.5?ng?mL^?1 for IPBATP-AC and 1.3–2.5?ng?mL^?1 for IPBATP-Ag-NP-AC. The proposed methods have been successfully applied for the extraction and determination of the understudy metal ions content in some real samples with extraction efficiencies higher than 90% and relative standard deviations (RSD) lower than 2.4%.     

Highly selective in situ metal ion determination by hybrid electrochemical "adsorption-desorption" and colorimetric methods

A novel and facile hybrid analytical method coupling electrochemical “adsorption–desorption” and colorimetric analyses was developed to detect heavy metal ions in turbid water samples. The target metal ions were deposited onto an electrode inserted into the original sample, which was referred to as the “adsorption” process. After changing the medium, the concentrated target metal ions were dissolved in a new, clean buffer (blank buffer), which was referred to as the “desorption” process. The concentrations of the target metal ions were measured by colorimetric analyses after the addition of specific indicator amounts. We demonstrated the applicability of this method by detecting Cd²⁺, Pb²⁺ and Cu²⁺ with co-depositing Bi³⁺ on portable screen-printed electrodes (SPEs). A good correlation (correlation coefficient of R = 0.997) was observed between concentrations ranging from 1 to 200 μM and absorbance values. After the multiple “desorption” process, the even better detection limits as low as 10, 10 and 100 nM were achieved for Cd²⁺, Pb²⁺ and Cu²⁺, respectively. The practicality of this hybrid method was confirmed by the detection of Cd²⁺, Pb²⁺ and Cu²⁺ in wastewater samples, and these results were in agreement with inductively coupled plasma atomic emission spectroscopy (ICP-AES). Overall, this hybrid method provides a simple, selective and effective technique for environmental pollutant analyses.