Lead Ion-selective Electrode Research Articles

A cathodically polarized PANI-based lead ion-selective electrode: achieving high stability with antibiofouling capabilities.

Solid-state contact ion-selective electrodes (SC-ISEs) are an efficacious means of monitoring heavy metal contamination. Instability of the electrode potential is a key factor limiting their development, with biofouling in real water samples posing a significant challenge to maintaining stability. Therefore, addressing biofouling is crucial for optimizing solid-state ion-selective electrodes. In this work, high stability and antibiofouling capability in a solid-state contact lead ion-selective electrode (SC-Pb2+-ISE) based on polyaniline (PANI) was achieved through cathodic polarization. Specifically, PANI played a dual role in the ion-selective membrane (ISM) as an ion-to-electron transducer and antifouling agent. Given the excellent electrochemical performance of PANI, the prepared electrode (GC/PANI-Pb2+-ISM) demonstrated a remarkable antibiofouling efficiency of 98.2% under a cathodic polarization of -0.2V. Furthermore, a standard deviation of standard potential (Eθ) as low as ± 0.5mV was realized successfully. The excellent chrono-potentiometric stability of 17.0 ± 2.9μV/s was also demonstrated. The electrode maintained a Nernstian response slope of 30.7 ± 0.2 (R2 = 0.998) after applying a cathode potential (-0.2V) for 30min. The developed GC/PANI-Pb2+-ISM electrode is suitable for practical applications in real environmental water sample monitoring.

A stable and low-fouling lead ion-selective electrode employing polyaniline-MXene composite for solid contact and polypeptide for antifouling

A biofouling-resistant solid-contact lead ion-selective electrode (Pb2+-ISE) with enhanced stability was developed based on dendritic peptides and polyaniline-MXene composites. The biofouling-resistant dendritic peptides, characterized by their high level of hydration and relative conformational entropy, effectively inhibit nonspecific adsorption. Simultaneously, the synergy between polyaniline nanowires and MXene nanosheets is harnessed to enhance the ion-electron transfer rate, thereby improving the stability of the ISE. The fabricated Pb2+-ISEs exhibit commendable electrochemical short-term stability and can rapidly respond to potential changes within 1 second. Under bacterial solution storage conditions, the peptide-modified ISEs maintain their Nernstian response without significant alteration for up to six days. Additionally, the Pb2+-ISEs are insensitive to O2, CO2, N2, and light, making them suitable for the analysis of Pb2+ in real complex samples. The strategic design incorporating dendritic peptides as a biofouling-resistant layer and the PANI-MXene composite as a conductive layer offers an effective approach to construct low-fouling ISEs capable of operating robustly in complex systems.

New Acrylate Co-Polymer Membrane Synthetized by Photo-Polymerization Technique for Lead (II) Ion-Selective Electrode

New Acrylate Co-Polymer Membrane Synthetized by Photo-Polymerization Technique for Lead (II) Ion-Selective Electrode

Preparation and Properties of Three Plasticiser-Free Novel Di-benzo-18-Crown-6 Aldimine-Derived Lead(II) Ion-Selective Electrodes

Three novel dibenzo-18-crown-6 aldimines were successfully synthesised and structurally characterised via various spectroscopic methods (1H,13H NMR, FT-IR) and their solution phase lead binding behaviours probed via absorption spectroscopy, the results are supported by Density Functional Theoretical (DFT) modelling. These methods revealed that the asymmetric nature of these compounds is such that at equilibrium the ether cavity adopts an open configuration where the constituent oxygen atoms exhibit a highly negative electrostatic potential; hence, they spontaneously (ΔG~−58 kJ mol−1) interact/bind aqueous lead ions to form stable 2:1 metal–ligand complexes. As indicated by cyclic and square voltammetry studies, all compounds are redox active and polymerise relatively easily onto a platinum surface to form a multi-layered lead Ion-selective Membrane (ISM), the structure of which is confirmed by Scanning Electron Microscopy (SEM) and Electrochemical Impedance Spectroscopy (EIS). These novel Ion-selective Electrodes (ISEs), as characterised by Differential Pulse Anodic Stripping Voltammetry (D PASV), allow selective electrochemical detection and quantification of lead at concentrations as low as 10 ppm, over a range of 15–60 ppm, with only minimal interference from mercury(II) and aluminium(III) ions at a 1:1 analyte-interferent ratio.

Antifouling improvement in Pb2+ ion selective electrodes by using an environmentally friendly capsaicin derivative

Biofouling is a critical issue for ion selective electrodes (ISE) in complex aqueous systems, seriously compromising the analytical performance of the electrodes (i.e., stability, sensitivity, and lifetime). Herein, an antifouling solid lead ion selective electrode (GC/PANI-PFOA/Pb2+-PISM) was successfully prepared by adding propyl 2-(acrylamidomethyl)-3,4,5-trihydroxy benzoate (PAMTB), an environmentally friendly capsaicin derivative, into the ion-selective membrane (ISM). The presence of PAMTB caused no loss in the detection performance of GC/PANI-PFOA/Pb2+-PISM (e.g., detection limit (1.9×10-7M), response slope (28.5±0.8mV/decade), the response time (20s), stability (8.6±2.9 μV/s), selectivity and no water layer), whilst imparting an excellent antifouling effect with an antibacterial rate of 98.1% when the content of PAMTB in the ISM was 2.5wt%. Further, GC/PANI-PFOA/Pb2+-PISM maintained stable antifouling properties, excellent potential response, and stability even after soaking in a high-concentration bacterial suspension for 7 days.

Gravimetric Complexometric Titration Method to Determine Mass Fraction of Ethylenediaminetetraacetic Acid Disodium Salt Dihydrate in Candidate-Certified Reference Materials

Titrations are a group of techniques that have contributed considerably to developing the chemical industry and chemistry itself. Currently, the Consultative Committee for Amount of Substance has recognized titration as one of the primary methods for determining the amount of substance. In this context, an accurate gravimetric complexometric titration method was implemented to determine the purity of ethylenediaminetetraacetic acid (EDTA) disodium salt dihydrate using a lead nitrate-certified reference material (CRM). The titration reaction was followed potentiometrically using a lead ion-selective electrode. The equivalence point was found by the inflection of a non-parametric regression line that fits the experimental data. The titrations were made in diluted ammonium hydroxide media and sodium tartrate was added to avoid the lead hydroxide precipitation that occurs at high pH. The effect of both concentrations, ammonium hydroxide and sodium tartrate, were evaluated by a Box-Behnken experimental design. A complete uncertainty statement for the measurement method is presented in terms of the International System of Units (SI). The combined relative standard uncertainty of the measurement results is 0.034 % for the purity of the EDTA disodium salt. The atomic weight of the lead that applies to the lead nitrate CRM was determined with mass spectrometry to decrease the uncertainty budget contribution of this parameter which, otherwise, would have been the most important. The main sources of uncertainty were the mass of the EDTA solution for titration blanks, the purity of the lead nitrate CRM, and the precision of the equivalence point determination. The method was evaluated using an EDTA disodium salt dihydrate CRM and no significant bias was found. Finally, the results indicated that the developed method could be used for the value assignment of the mass fraction of EDTA disodium salt dihydrate to produce CRMs.

Fabrication of Lead Ion Selective Electrodes (Pb-ISE) based on Poly Methyl-Methacrylate-Co-Butyl Acrylate (MB28) Thin Film Photo-polymers and Pencil Graphite Electrodes (PGEs)

Fabrication of Lead Ion Selective Electrodes (Pb-ISE) based on Poly Methyl-Methacrylate-Co-Butyl Acrylate (MB28) Thin Film Photo-polymers and Pencil Graphite Electrodes (PGEs)

Prototyping of a Low-Cost Ion-Selective Electrode Sensor Unit for Determination of Lead Ions in Aqueous Samples

Exposure to lead via drinking water is a substantial health hazard. The current common practice of measuring lead levels in drinking water is to use analytical chemical analysis that involves sophisticated laboratory instruments. As lead contamination in drinking water is often a close-to-home contamination caused by corroded lead service pipes connecting households to main lines or lead-based pluming within the households, a low-cost and portable device that can be conveniently deployed to individual households to monitor lead levels in drinking water would offer consumers the opportunity to obtain first-hand information about the lead levels in their drinking water. The main objective of this study is to develop and prototype a portable low-cost device for detecting lead levels in drinking water. The lead-detecting device consists of two primary components: lead ion-selective electrode (ISE) sensing membrane and a microcontroller-based measuring unit. ISE membrane has proven to show low detection limits, good selectivity, low cost and great potential to be integrated in a miniature device. The ISE membrane in this study utilized polymeric membrane as the matrix with lead-selective ionophores embedded in the matrix. Hydroxyl type Vinyl Chloride-vinyl Acetate Terpolymer was used to create polymeric membrane matrix and allowed for all components to be housed in the membrane. The selected ionophore was Tert-Butylcalix(4)Arene-Tetrakis with its primary function is to differentiate and transport a specific ion (in this case, Pb2+ ions) through a membrane. A limit of detection of 1.0 ´ 10-8 M was achieved along with a linear Nernstian response over a lead concentration range from 1.0 ´ 10-8 M to 1.0 ´ 10-4 M. Durability test of the membrane showed a lifetime close to 30 days. A low-cost printed circuit board (PCB) was custom designed and created as an amplification unit to measure the ISE’s electromotive force (EMF). The custom-built device was able to capture the limit of detection (LOD) of the ISE sensing membrane and showed reasonably good consistency in comparison to measurements from commercial potentiostat.

Development and application of a novel lead ion-selective electrode with the alkylamines modified molecular sieve as carrier

Development and application of a novel lead ion-selective electrode with the alkylamines modified molecular sieve as carrier

Lead ion selective electrodes from dibenzo-18-crown-6 derivatives: An exploratory study

Dibenzo-18-crown-6 (DB18C6) and three of its derivatives (-COCH3, -Br, -NO2), are investigated via Density Functional Theoretical (DFT) modelling, Fourier Transform Infrared (FT-IR) and absorption spectroscopies, Differential Pulse Anodic Stripping (DPASV), Cyclic (CV) and Square Wave (SWV) voltammetries, as possible materials for preparing plasticiser free lead(II) ion selective electrodes. The spontaneous, entropy driven, interactions between lead(II) ions and DB18C6 derivatives are such that they form 1:1 complexes via coordination with the high electron density open ether cavity, except for the brominated derivative where the metal: ligand stoichiometry is 2:1 due to exo-cavity coordination via the high electron density bromine atoms. Monolayers resulting from electropolymerization of some derivatives (-H, -COCH3, -Br) and chemisorption of the -NO2 derivative, allows quantification of lead(II) ions at concentrations below 10 mg L−1 with minimal interference from other metal ions except Hg2+ and Al3+.

An integrated measurement of six response performance indicators for lead ion-selective electrodes and application.

A heavy metal ion-selective electrode (ISE) with highly multiple response performances, rather than a high single response performance, is needed urgently for in situ, real-time environmental monitoring. In this study, we present an integrated measurement of six response performance variables such as the response slope, selectivity, dynamical range, detection limit, response time, and lifetime. They are selected and used as the indicators of the quality assessment for Pb2+-ISEs. The measurement, named as electrode comprehensive quality index (IECQ), is a single number for a given ISE. The comprehensive qualities of 114 Pb2+-ISEs reported in the literature were evaluated through the index method. Twenty-one Pb2+-ISEs-based polymer membrane with top 3 IECQ values for seven different properties have been recommended by evaluating and screening of the electrodes. Five Pb2+-ISEs-based polymer membrane with the best single response performance were also provided. The recommended Pb2+-ISEs, along with the corresponding Pb2+-ISEs with the miniaturized configurations, will provide helpful guideline for the application of Pb2+-ISE with highly multiple response performances in real-time environmental monitoring.

The New Lead (II) Ion Selective Electrode Based On Free Plasticizer Film of pTHFA Photopolymer

This research has succeeded in developing a Lead (II) –Ion-selective electrode (Pb2+-ISE) sensor based on poly-tetrahydro furfuryl acrylate (pTHFA) films free plasticizers utilizing photo-polymer technique. The Pb2+-ISE has a performance that includes a linear range of 0.1–10−5 M, Nernstian number 26.5–29.8 mV/dec and LOD 3.24–3.98 (× 10−6) M, where the optimum composition between KTpClPB lipophilic salt with leads (IV) ionophore is 1:1 mole ratio. The Pb2+-ISE sensor also shows a relatively good selectivity value (Log Kpota,b) against several interfering ions including K+ −6.5 ± 0.3, Na+ −6.2 ± 0.1, NH4+ −6.7 ± 0.1, Mg2+ −12.7 ± 0.2, Cu2+ −4.2 ± 0.5 and Cd2+ −6.1 ± 0.2, where the response of the Pb2+-ISE sensor is stable at pH 3–8. In this study, the Pb2+-ISE sensor shows validation test results that are comparable to measurements using atomic absorption spectroscopy (AAS) devices using artificial solutions and real sample. The results of testing with artificial solutions successively produced Pb2+ concentrations of 9.5 ± 0.3, 52.5 ± 1.7, and 100.8 ± 2.5 ppm, while for real samples the Cisadane river was 0.0025 ± 0.45 ppm and the refueling station was 18.15 ± 16.74 mg/kg soil sample.

Development of a Graphene Paper-Based Flexible Solid-Contact Lead Ion-Selective Electrode and its Application in Water

Abstract. A graphene paper-based flexible solid-contact ion-selective electrode (SC-ISE) was developed to detect lead ion sensitively. Graphene paper obtained via a simple vacuum filtration method was used as the electrode substrate for direct coating of an ion-selective membrane. The Nernstian slope of the prepared paper-based potentiometric sensor toward lead ion detection was demonstrated as 29.4 mV per decade. A detection limit as low as 2.5 × 10-7 mol L-1 was achieved. Reversed chronopotentiometry and water layer test revealed that the graphene paper-based SC-ISE possessed excellent potential stability because of the hydrophobicity of graphene paper. Furthermore, reliable data were obtained from the detection of lead ion levels in real water samples using the graphene paper-based potentiometric sensor, which shows great potential in practical application. Keywords: Graphene paper, Heavy metal, Ion-selective electrode, Potentiometry, Water sample.

Synthesis and characterization of graphene Th(IV) phosphate composite cation exchanger: analytical application as lead ion-selective membrane electrode

A Pb2+ ion-selective membrane electrode (ISME) based on graphene Th(IV) phosphate composite cation-exchange material was fabricated using solution casting method. The effect of membrane composition on the proton conductivity was investigated using varying amounts of electroactive material. The membrane with 250 mg of electroactive material and 10μl of plasticizer exhibited highest proton conductivity. The optimized membrane composition was used for the fabrication of ISME which exhibited a typical Nernstian response towards Pb2+ ions in the concentration range 1.0 × 10−1 to 1.0 × 10−7 M with a sub-Nernstian slope of 27.65 mV per decade change in Pb2+ ion concentration. The response time of this electrode for Pb2+ ions was found to be 10 s and the electrode can be used for 120 d without any considerable divergence in response potential and can be used in the pH range from 3.0 to 7.0. It was found selective for Pb2+ ions in the presence of various monovalent and multivalent interfering ions. It was also employed as an indicator electrode in the potentiometric titration of Pb2+ ions using ethylenediamine tetraacetic acid, disodium salt as titrant.

Lead(II) ion selective poly(aniline) solid contact electrode based on 1,2-bis(N′-benzoylthioureido)ethane, -propane and -butane ionophores

The lead ion selective electrodes were manufactured by synthesizing a benzoyl thioureido group ionophores having two sulfur groups on the both ends of ethane, propane and butane molecules. The ionophore containing propane moiety showed the best responsivity to lead ion. With the 1,3-bis(N,N′-benzoylthioureido)propane (BTP) ionophore, the best result was found when it included with the o-nitrophenyloctylether (o-NPOE) plasticizer with the highest permittivity and the oleic acid (OA) additive. The ratio of BTP: polyvinyl chloride: o-NPOE: potassium tetrakis(4-chlorophenyl)borate: OA was 2.5: 16.5: 30.5: 1.5: 0.5, the response range was 1.0 × 10−6.4–1.0 × 10−1.0 M, and the response slope was 30.4 mV/decade. Addition of OA led to an excellent result for the responsivity, cation interference effect, correlation coefficient, response time and reproducibility. The electrode represented constant characteristics irrelevant to variation of pH between 2–7, the stabilization time was 30 s, the response time was about 30 s, and the reproducibility represented ±0.81 and ±1.40 mV for 1.0 × 10−2.0 and 1.0 × 10−3.0 M lead, respectively.

Synthesis and characterisation of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) Zr(IV) monothiophosphate composite cation exchanger: analytical application as lead ion selective membrane electrode

A Pb2+ ion selective membrane electrode based on poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) Zr(IV) monothiophosphate composite cation exchange material was fabricated using solution casting method. The effect of membrane composition on the proton exchange capacity was investigated by using varying amounts of electroactive material. The membrane with 250 mg of electroactive material and 10 µL of plasticiser exhibited higher proton conductivity. The optimised membrane composition was used for the fabrication of ion selective membrane electrode which exhibited typical Nernstian response towards Pb2+ ions in the concentration range 20.70 gL−1–20.7 µgL−1 (1 × 10–1–1 × 10–7 mol L−1) with a sub-Nernstian slope of 27.429 mV per decade change in Pb2+ ion concentration. The response time of the electrode under study for Pb2+ ions was found to be 11 s and the electrode can be used for 120 days without any considerable divergence in response potential. It can also be successfully used in the pH range from 3.0 to 6.5. It was found selective for Pb2+ ions in the presence of various monovalent, divalent and trivalent interfering metal ions. It was also employed as an indicator electrode in the potentiometric titration of Pb2+ ions using ethylenediaminetetraacetic acid, disodium salt, as a titrant.

Optimization of Polyaniline Supported Ti(IV) Arsenophosphate Composite Cation Exchanger Based Ion-Selective Membrane Electrode for the Determination of Lead

Polyaniline supported Ti(IV) arsenophosphate [PANI Ti(IV) AsP] composite cation exchange material was synthesized by a simple chemical route. To explore the application of this composite material, a lead ion selective membrane electrode was fabricated. The composite membrane electrode demonstrated a Nernstian response of 29.3 mV per decade change in concentration of Pb2+ ions over a wide concentration range (1 × 10–1–1 × 10–6 M) with a detection limit of 1 × 10–6 M. Mixed solution method was used to determine the selectivity of Pb2+ ions in the presence of interfering cations. The practical utility of PANI Ti(IV) AsP membrane electrode has been fruitfully explored by using it as an indicator electrode for potentiometric determination of lead.

Tetramethylthiuram monosulfide를 ionophore로 이용한 납 이온 선택성 poly(aniline) 고체 접촉 전극

Tetramethylthiuram monosulfide를 ionophore로 이용한 납 이온 선택성 poly(aniline) 고체 접촉 전극

1-Hexyl-3-methylimidazolium hexafluorophosphate as new component of polymeric membrane of lead ion-selective electrode

abstract The ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate is used as a new lipophilic ionic additive in the polymeric membrane of a solid contact type lead ion-selective electrode. The membrane is deposited on an internal glassy carbon electrode with poly(3-octyl)thiophene as an intermediate layer. The sensor exhibits good analytical parameters: low detection limit of 3.5 × 10−9 mol L−1, Nernstian response slope of 29.8 mV/decade, a wide concentration range of 1 × 10−8−1 × 10−1 mol L−1, short response time of 7 s, and relatively long lifetime of 100 days. The proposed sensor has a working pH range of 4.0–6.9 and excellent selectivity for Pb(II) ions over a wide variety of other metal ions. The efficiency of the proposed sensor was demonstrated by its application for direct determination of Pb2+ ions in real water samples.

Lead (II) Ion-Selective Membrane Electrodes Based on Four Nitrogen-Containing Heterocyclic Thioethers

Lead (II) Ion-Selective Membrane Electrodes Based on Four Nitrogen-Containing Heterocyclic Thioethers