Poly Vinyl Chloride Membrane Research Articles

Potentiometric chemical sensors for the detection of paralytic shellfish toxins

Potentiometric chemical sensors for the detection of paralytic shellfish toxins have been developed. Four toxins typically encountered in Portuguese waters, namely saxitoxin, decarbamoyl saxitoxin, gonyautoxin GTX5 and C1&C2, were selected for the study. A series of miniaturized sensors with solid inner contact and plasticized polyvinylchloride membranes containing ionophores, nine compositions in total, were prepared and their characteristics evaluated. Sensors displayed cross-sensitivity to four studied toxins, i.e. response to several toxins together with low selectivity. High selectivity towards paralytic shellfish toxins was observed in the presence of inorganic cations with selectivity coefficients ranging from 0.04 to 0.001 for Na+ and K+ and 3.6*10−4 to 3.4*10−5 for Ca2+. Detection limits were in the range from 0.25 to 0.9 μmolL−1 for saxitoxin and decarbamoyl saxitoxin, and from 0.08 to 1.8 μmolL−1 for GTX5 and C1&C2, which allows toxin detection at the concentration levels corresponding to the legal limits. Characteristics of the developed sensors allow their use in the electronic tongue multisensor system for simultaneous quantification of paralytic shellfish toxins.

New Simple Ion-Selective Membrane Electrode for Serious Environmental Pollutant, Mercury (II), Analysis in Aqueous Solution, Fluorescent Mercury Lamp White Dust, Mercurochrome and Dental Alloy

Background: Mercury in various forms constitute a serious environmental pollutant. Its exposure is still considered a world related risk for individuals in numerous manufacturers. The Context and Purpose of the Study: Because of it serious hazardous effects to human health, there is strong need to develop new tools for mercury ion determination in clinical analysis and environmental monitoring. This investigation describes for the first time the construction of a polyvinyl chloride (PVC) membrane electrode which is exceedingly specific to divalent mercury was formed by utilizing Hg[dimethylglyoxime (phene)]2+ as a suitable carrier. Results: The sensor exhibits a Nernestian response for mercury ions over a wide concentration range (5x10-7-5x10-2 molL-1) with a slope of 29±0.5 mV per decade. It has a reaction time of 30s and can be utilized for 2 months with no quantifiable divergence in potential. The electrode can be used in the pH range from 1.8-4.5.The average recovery obtained is 91.0% with standard deviation of 1.5% (n=8). Conclusion: The proposed sensor demonstrates genuinely great segregating capacity towards mercuric ions in correlation with some heavy metals. This sensor was utilized for the quantitative analysis of mercuric ions in its aqueous solution. Also, was applied in potentiometric titration as an indicator electrodefor Hg2+ in various real samples (e.g.; fluorescent mercury lamp white dust, mercurechrome and dental alloy). Keywords: Mercury(II) ion-selective electrode, PVC membrane, potentiometry, coated graphite rod, mercurochrome, dental alloy.

Studying the Effect of Membrane Thickness on the Performance of Green ISE-Potentiometric Sensors: Application to Ritodrine HCl and Its Active Impurity, Tyramine

Factors affecting the performance of polyvinyl chloride (PVC) based ISE were recently the scope of study by several researchers; however, no enough data has related to the thickness of the PVC membrane to performance characteristics and sensitivity of sensors. The current work introduces an ecofriendly experimental approach to evaluate the effect of membrane composition including ion exchanger and plasticizer along with thickness on the performance of a PVC sensor for determination of a tocolytic selective ß2-agonist; ritodrine HCl (RTH), in presence of its active impurity, tyramine. Thirteen different PVC membranes were prepared by varying the content of ion exchanger types and amounts constructing different thickness to address their effect on their performance characteristics. A comparative study was held among the fabricated sensors for determination of RTH in pharmaceutical dosage form, and biological fluids including human plasma and urine. It was found that the thickness of liquid membrane electrodes had a remarkable effect on the sensitivity of PVC based ion-selective electrode. The proposed sensors proved acceptable selectivity for RTH against tyramine and common inorganic species. The proposed technique presents a green alternative to reported ones by saving cost, time and effort, and yielding of the minimum amount of wastes.

All-Solid-State Screen-Printed Sensors for Potentiometric Calcium(II) Determinations in Environmental Samples

This paper describes preparation, characterization and electrochemical performance of novel planar miniaturized all-solid-state (ASS) screen-printed potentiometric sensors for the detection of Ca2+ ions in environmental samples. Screen-printed graphite-based ion-selective electrodes (ISEs) and screen-printed reference electrodes based on silver-containing pastes have been applied in a space saving manner on common ceramic substrates with small dimensions. Applications to environmental samples are shown by direct potentiometry and potentiometric titrations in real water samples. Conducting polymers (CPs) have been used as solid-contact materials and as intermediate layer between the polyvinyl chloride (PVC)-containing ion-selective membrane and the graphite-containing substrate. Different diamides have been incorporated into the PVC membrane. In the range from 10-4 mol/L to 10-1 mol/L, the ISEs show linear slopes of 27 mV/decade, which is close to the Nernstian response. Moreover, the ISEs have response times of 6 months. The novel potentiometric ASS sensors enable simple and exact Ca2+ determinations in real samples.

A New Highly Selective Neodymium(III) Polyvinylchloride Membrane Electrode Based on 4-Hydroxypyrrolidine-2-Carboxylic Acid as an Active Material

The present paper describes the fabrication of a new polyvinylchloride (PVC) membrane electrode for the determination of Nd(III) ion based on 4-hydroxypyrrolidine-2-carboxylic acid (LHP) as an active material along with sodium tetraphenyl borate (NaTPB) as an anionic additive and acetophenone (AP) as solvent mediator. The optimum composition (%, w/w) of the best performing membrane contained 66 AP, 30 PVC, 2 NaTPB and 3 LHP. The basic analytical parameters of this electrode such as slope characteristics, detection limit, response time, selectivity and pH effect were assessed. The electrode displayed a Nernstian response in terms of slope (20.5 ± 0.4 mV per decade) and response time (~8 ± 1 s) over a wide neodymium ion concentration range of 10–6 to 10–2 M with a detection limit of 7.5 × 10−7 M. The potentiometric response of the electrode was constant in the pH range of 3.2‒8.9. According to the selectivity coefficients determined by the matched potential method, the interference of many common alkaline, alkaline earth, transition, heavy metals and specially lanthanide ions in determination of Nd(III) ion was very low. The proposed electrode has been successfully used as an indicator electrode in the potentiometric titration of Nd(III) ion with EDTA and applied for determination of Nd(III) ion in mixtures of different ions.

Ionophore Properties of Schiff Base Compounds as Ion Sensing Molecules for Fabricating Cu(II) Ion-Selective Electrodes

Bis(2-hydroxybenzaldehyde)-1,2-diaminoethane (LI), bis(2-hydroxybenzaldehyde)-1,3-diaminopropane (LII) and bis(2-hydroxybenzaldehyde)-4,4'-methylendianiline (LIII) were examined as ionophores for fabrication of polyvinylchloride (PVC) membrane Cu(II) ion-selective potentiometric sensors. The optimum composition (%) for the sensors was: 5 LI, 30 PVC, 6 sodium tetraphenylborate (NaTPB), 59 ortho-nitrophenyloctyl ether (NPOE); 4 LII, 30 PVC, 5 NaTPB, 61 dibutyl phthalate; 6 LIII, 30 PVC, 5 NaTPB, 59 NPOE. The linear response range of the electrodes was 5 × 10–4–0.05 (LI), 5 × 10–4–0.1 (LII) and 1 × 10–6–0.01 M (LIII), and the corresponding detection limits were 4 × 10–4, 4 × 10–4 and 2 × 10–7 M, respectively. The sensors were showed rapid response time (≈10 s). Their responses were independent on pH in the range 2.5–5.0 (LI), 3.2–4.7 (LII) and 4.0–5.0 (LIII). The selectivity of the prepared electrodes towards copper ions over some mono-, di- and trivalent metal ions was evaluated. The sensors were used as indicator electrode in potentiometric titration of copper ions in aqueous solutions.

Kajian Pemanfaatan Silika dari Sekam Padi dalam Pengolahan Limbah Tekstil

Abstract – Textile industry is one of the waste contamination industries that can pollute the environment, so that the rapid development of textile industry must be followed by the improvement of its sewage treatment system. Along with the global issue of Green Manufacturing, the textile industry waste treatment can promote environmentally friendly waste treatment process and derived from renewable substances. Therefore, it is necessary to study the utilization of rice husk silica in the processing of textile waste. The results of the study provide information that textile wastes come from all processes in the textile industry, from pretreatment to finishing. Rice husk ash silica is a material utilized adsorption of textile waste or mixture of PolyVinylChloride (PVC) membrane material to filter textile waste. The characteristics of rice husk silica are influenced by the extraction method. The initial washing process using acid and then combustion at 600 ° C - 750 ° C produces a relatively high purity of silica with a maintained silica amorphous level.Keywords: Rice Husk Silica, Textile Waste, Textile Waste Processing, Silica Characteristic

Development and Validation of Potentiometric ZnO Nanorods Modified Ion Selective Electrode for Determination of Gemifloxacin in Pharmaceutical Formulation

Potentiometric method for determination of Gemifloxacin (GEMI) by ion selective electrode based on ZnO nanorods incorporation with HPβ-CD as sensing ionophore and (KTFPB) potassium tetrakis- (3,5(Triflouromethyl) Phenyl Borate) ion as anionic site (additive) in Polyvinyl Chloride (PVC) membrane, without inner reference solution was developed. The sensor shows 'nearly Nernstian response over a concentration range (0.5-10000 μM) with a slope of 33.65 mv decade-1 of concentration with a Limit of Detection (LOD) 0.1500 μM.

Performance evaluation of polyvinylchloride/polyacrylonitrile ultrafiltration blend membrane

Polyvinylchloride (PVC) membranes were modified by blending with polyacrylonitrile (PAN) as a second polymer. The miscibility of PVC/PAN blend was examined using an incompressible regular solution (CRS) model in no need to make a membrane. The results showed that the PVC/PAN blend was immiscible for all compositions at a temperature range of −25 to 225 °C. Furthermore, the prediction of the phase behavior of a PVC/PAN/DMF ternary system showed that the blend of two polymers was highly incompatible even in their common DMF solvent. However, this incompatibility led to a remarkable increase in the porosity of the blend membrane and pure water flux compared to those for pure PVC membrane. The pure water flux of the PVC membrane (37.9 ± 1.5 L/m2 h) increased about 41 and 76% by adding 10 and 20 wt% PAN, respectively. The blend membranes also showed an enhanced flux recovery ratio (FRR) compared to a pure PVC membrane, although the PVC membrane rejection for Bovine serum albumin (BSA) was decreased after blending with PAN. The PVC/PAN (90/10) blend membrane was subjected to hydrolysis with NaOH alkaline solution at three different concentrations and contact times to further enhance its performance. The membrane, which was hydrolyzed with a 0.5 mol/L NaOH solution for 0.5 h, showed a highest pure water flux of 75.6 ± 7.2 L/m2 h due to its increased hydrophilicity. This membrane also revealed an improved FRR and better thermal and mechanical properties compared to an unmodified membrane.

A new Co(III) complex of Schiff base derivative for electrochemical recognition of nitrite anion

The synthesis and characterization of a new Co(III) complex of a salphen-type Schiff base ligand, (E)-2-{[(2-aminopyridin-3-yl)imino]methyl}-4,6-di-tert-butylphenol (HL), are reported. The characterization has been carried out using X-ray single crystallographic, thermogravimetric, and spectroscopic techniques. The complex has been combined with polyvinyl chloride (PVC) membrane of various compositions and tested as an electrochemical electrode towards recognition of several anions. The electrode exhibits exceptional electrochemical recognition for the nitrite $$(\hbox {NO}_{2}^{-})$$ anion in aqueous media. The electrode exhibited a linear response to $$\hbox {NO}_{2}^{-}$$ with a detection limit of $$5.76\,{\upmu }\hbox {M}$$ and displayed a linear Nernstian slope over the nitrite concentration range of $$1.0 \times 10^{-5}$$ – $$1.0\times 10^{-1}\,\hbox {M}$$ in the pH range of 3–7 and a fast response time of less than 10 seconds. Theoretical calculations showed that the sensing could be via anion exchange in the Co(III) complex. SYNOPSIS An octahedral Co(III) complex of the salphen-type Schiff base, (E)-2-{[(2-aminopyridin-3-yl)imino]methyl}-4,6-di-tert-butylphenol, was synthesized, characterized and analyzed for its electrochemical anion recognition property through reversible anion exchange mechanism.

All-Solid-State, PVC Membrane, and Carbon Paste Ion-Selective Electrodes for Determination of Donepezil Hydrochloride in Pharmaceutical Formulation.

All-solid-state, polyvinyl chloride (PVC) membrane, and carbon paste potentiometric ion-selective electrodes (ISEs) were proposed for the determination of donepezil hydrochloride (DON) in the drug substance and a pharmaceutical formulation. The potentiometric response toward DON was based on the existence of donepezil-tetraphenyl borate (DON-TPB) in a PVC membrane or a carbon paste in the presence of dioctylphthalate. In contrast, the solid-state electrode was prepared by direct incorporation of DON-TPB into a commercial nail varnish without external additives. The electrodes exhibited Nernstian slopes of 55.0, 57.0, and 53.0 mV/decade over the concentration ranges of 1 × 10-5 to 1 × 10-3, 1 × 10-4 to 10-2, and 1 × 10-4 to 5 × 10-3 for the solid-state, PVC membrane, and carbon paste electrodes, respectively. The response of the electrodes is independent of pH in the range of 2-≤8. The electrodes showed good selectivity for DON with respect to a number of inorganic cations and amino acids. The electrodes were used for the determination of DON in pure solution and in pharmaceutical tablets with high accuracy (±2%) and precision (RSD ≤2%). The solid-state electrode is simple, economical, and rapid when compared to the PVC membrane and carbon paste electrodes.

A novel Ce(IV) ion-selective polyvinyl chloride membrane electrode based on HDEHP and HEH/EHP

A novel Ce(IV) ion-selective polyvinyl chloride (PVC) membrane electrode based on HDEHP and HEH/EHP as ionophore was successfully prepared. The factors affecting the response of Ce(IV) ion were investigated, such as membrane composition, internal solution, concentration of SO42−, and acidity in test solution. The best performance was obtained using the membrane with PVC:DBP:HDEHP:HEH/EHP:OA mass ratio of 75:175:5:5:5. The proposed electrode exhibited a Nernstian slope of 30.44 mV/decade for Ce(IV) ion over a linear concentration range of 1×10−5–1×10−1 mol/L with the detection limit of 9.0×10−6 mol/L. The electrode showed stable response within the SO42– concentration range of 0.1–1 mol/L and the acidity range of 0.25–1.2 mol/L H+. The proposed electrode showed high selectivity for Ce(IV) over a wide variety of interfering ions and a fast response time. It was used as an indicator in the potentiometric titration of Ce(IV) solution with H2O2 solution, and could also be used for the determination of Ce(IV) in real Ce(IV)-containing aqueous samples.

New polyvinyl chloride/thermoplastic polyurethane membranes with potential application in nanofiltration

Due to favorable interactions between Polyvinyl chloride (PVC) and Thermoplastic Polyurethane (TPU) chain segments as revealed by viscosity measurement and differential scanning calorimetry (DSC), the ternary phase diagram of the PVC/TPU blend (for all compositions) was almost close to that of neat PVC. According to a simple diffusion model used for studying the kinetics of membrane formation, the PVC/TPU membrane structure was expected to be almost similar to that of PVC membrane which was supported by scanning electron microscope (SEM) micrographs. PVC membranes were impermeable to water up to a transmembrane pressure of 8bar. Interestingly, adding TPU to PVC lowered the pressure at which the membrane showed permeability. Addition of 25wt% TPU to PVC led to a substantial increase of pure water flux from 3.4 to 111.4L/m2h along with no change in the separation performance (100% Coomassie Brilliant Blue (CBB) dye rejection). However, further increase of TPU content beyond 25wt%, caused a remarkable loss in membrane performance where under a specific threshold pressure the pure water flux increased steadily with time. This phenomenon being reversible below and above the threshold pressure was ascribed to the high elasticity of TPU, justified by mechanical evaluation of membranes and their glass transition temperature.

Electrochemical Determination of Cadmium, Lead, and Nickel Using a Polyphenol–Polyvinyl Chloride—Boron-Doped Diamond Electrode

ABSTRACTBoron-doped diamond electrode surfaces were modified by a polyphenol—polyvinyl chloride membrane. The polyphenols were extracted from the skin of acorns, the fruit of the oak tree. The polymer film was applied on the boron-doped diamond electrode surface by solvent evaporation. The resulting polyphenol–polyvinyl chloride–boron-doped diamond electrode was used as a sensor for cadmium, lead, and nickel. The synergy between the chemically modified surfaces and electrochemical performances of the boron-doped diamond microcell electrode was examined by differential pulse anodic stripping voltammetry at nanomolar concentrations of the three metal ions. The modified electrode provided a stable, sensitive, and selective response to cadmium, lead(II), and nickel(II) ions. The resulting detection limits were 0.0221, 0.25, and 0.00424 nmole L−1, respectively.

A new PVC matrix membrane sensor for determination of praseodymium(III) ion based on bis(salicylaldehyde)thiocarbohydrazone as an ion carrier

The sufficient amounts of bis(salicylaldehyde) thiocarbohydrazone (STCH) as a lipophilic selective element (3%, w/w), sodium nitrobenzene (NB) as a plasticizer (64%, w/w), tetraphenyl borate (NaTPB) as an anionic additive (3%, w/w), and poly vinyl chloride (PVC) as a polymeric matrix (30%, w/w) was employed to form a PVC membrane of a new Pr3+ ions selective sensor to apply as an indicator electrode in analytical applications. The best electrode response was observed in the slope (19.5 ± 0.7 mV per decade) over a wide concentrations from lower (1.0 × 10−6 mol L–1) to higher (1.0 × 10−2 mol L–1) of Pr3+ ion solution with a detection limit of 8.5 × 10–7 mol L–1. This electrode showed the fast response time about 10 second for praseodymium ion concentration range of 1.0 × 10–6 to 1.0 × 10–2 mol L–1, in the pH range of 2.3–7.9. The matched potential method was applied to study the selectivity of electrode toward Pr3+ ions in comparison with many common cations. The results showed the negligible disturbance of all other cations on the proposed praseodymium(III) electrode. The making sensor has been employed successfully as an indicator electrode in the potentiometric titration of praseodymium(III) solution with EDTA at pH 6.0. Moreover the applicability of the sensor was studied in determination of Pr3+ ion in mixtures of different ions.

Electrochemical methods for the determination of heparin

A review of studies on the determination of heparin in various samples (pharmaceuticals, biological fluids) by electrochemical methods of analysis in 1976–2014 is presented. Heparin is most often determined in pharmaceuticals by polarography using cationic dyes, and in biological samples, by differential pulse methods on non-stationary mercury electrodes. Works on the creation of heparin-selective electrodes coated with a polyvinylchloride membrane with quarternary ammonium salts are most promising; they can, probably, be used for the creation of portable devices for the determination of heparin.

Towards stabilization of the potential response of Mn(III) tetraphenylporphyrin-based solid-state electrodes with selectivity for salicylate ions

We report a new type of solid-state electrode (type I) of a simple design with polyvinyl chloride membranes based on Mn(III) tetraphenylporphyrin and with graphite as the electronically conducting substrate. Enlargement of the membrane/graphite contact area by soaking graphite in the plasticizer with subsequent conditioning of the electrode at 30 °C allowed us to shorten the time required to achieve steady potential values of the sensors to just 3 days. These electrodes do not require a specially added RedOx system in the transducer layer. Stabilization of the EMF response of type I electrodes is compared to type II electrodes which contain a Cu0/Cu2+ RedOx couple in the transducer layer. Type I sensors are suitable for measuring the salicylate ion concentration in the clinically important concentration range down to 2.5 × 10−4 M with a sensitivity to salicylate ion of −59.0 mV decade−1 in solutions with a high constant background of chloride ions of 0.12 M at pH = 5.3, making this a promising technique for an effective design of solid-contact ion-selective electrodes with polymeric sensing membranes.

Preparation, characterization and application of GO-TiO2/PVC mixed matrix membranes for improvement in performance

Abstract Poly vinyl chloride (PVC) membranes are known for their low cost as well as good mechanical, thermal and chemical stability. However, the inherent hydrophobicity of the PVC material leads to fouling of membrane. Thus, in this paper, we have attempted to use GO-TiO2 nanosheets-blended PVC membranes. GO-TiO2 nanosheets are blended in the casting solution containing PVC and polyvinylpyrrolidone (PVP). Filtration experiments show that blending of GO-TiO2 sheets enhanced the permeate flux while keeping the rejection of humic acid almost same. The results are supported by characterizations like SEM, EDX, TEM, AFM, XRD and contact angle measurements.

Fabrication of a Developed Potentiometric Ibuprofen Electrode Based on New Functionalized $\beta$ -Cyclodextrins for Pharmaceuticals Determination

New polyvinyl chloride membrane electrodes based on the functionalised $\beta $ -cyclodextrin: heptakis (2, 3, and 6-tri-O-benzoyl)- $\beta $ -cyclodextrin and 2-hydroxy-3-N, N, N-trimethyl-amino) propyl- $\beta $ -cyclodextrin chloride for ibuprofen have been prepared. The optimum membranes with methyltrioctyl ammonium chloride as positive charge additive are characterised by a Nernstian response slope of 59.46 mV decade−1 over the linear range of $5\times 10^{-5}$ – $1\times 10^{-2}$ mol L−1 and the detection limit $2.5\times 10^{-5}$ mol L−1, as well as the response time of 7 (seven) s. It can be used within the pH range 5.1–9.1 for 15 months without any considerable deterioration. Incorporation of $\beta $ -cyclodextrins improved the electrode selectivity towards ibuprofen ions from several inorganic and organic interferents and some common drug excipients due to non-covalent interactions (host molecule-guest molecule). The notable advantages of the ibuprofen selective electrode include its high reversibility of potential, cost-effectiveness, as well as accurate and comfortable application. The sensor was applied for the determination of ibuprofen in pharmaceutical preparations, and in real water samples (tap, bottled, and river water) by the study of the recovery of ibuprofen, using standard addition methods.

An aluminum selective electrode via modification of PVC membrane by modified clinoptilolite nanoparticles with hexadecyltrimethyl ammonium bromide (HDTMA-Br) surfactant containing Arsenazo III

A modified PVC (polyvinyl chloride) membrane with clinoptilolite nanoparticles/hexadecyltrimethyl ammonium bromide surfactant (HDTMABr)/Arsenazo III: (NSMZ-ARS), was used for construction of Al(III) –selective electrode. The raw and modified samples were characterized by XRD, FTIR, SEM and TEM methods. Among the different tested membranes constructed by raw and modified samples, only, the membrane electrode containing NSMZ-ARS showed a suitable Nernstian response to aluminum in the concentration range of 2.04×10−5 to 1.99×10−1M (r=0.9987), with a detection limit of 1.0×10−5molL−1 and a Nernstian slope of 19.6±0.5mV per decade of aluminum concentration. The electrode response to aluminum remained constant in the pH range of 2–4. The sensor was selective for aluminum over a wide variety of other ions and exhibited. The electrode had a rapid response time and its response reached to steady potential at 5s. The electrode had also satisfactory long term stability and held its activity at least 3months.