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.     

Chromium(III) Ion Selective Electrode Based on Oxalic Acid Bis(Cyclohexylidene Hydrazide)

A poly(vinyl chloride) membrane sensor based on oxalic acid bis (cyclohexylidene hydrazide) as membrane carrier was prepared and investigated as a Cr(III)‐selective electrode. The electrode reveals a Nernstian behavior (slope 19.8±0.4 mV decade^?1) over a wide Cr(III) ion concentration range 1.0×10^?7–1.0×10^?2 mol dm^?3 with a very low limit of detection (i.e., down to 6.3×10^?8 mol dm^?3). The potentiometric response of the sensor is independent of the pH of the test solution in the pH range 1.7–6.5. The electrode possesses advantage of very fast response, relatively long lifetime and especially good selectivity to wide variety of other cations. The sensor was used as an indicator electrode, in the potentiometric titration of chromium ion and in the determination of Cr(III) in waste water and alloy samples.     

Development of Pr(III) Selective Electrode Using 1,6,7,12‐Tetramine‐2,5,8,11‐tetraoxo‐1(12),6(7)‐di(biphenyl)‐dodecane (TATODBDD) as a Neutral Carrier

A polyvinyl chloride (PVC) membrane based Pr(III) selective electrode was constructed using 1,6,7,12‐tetramine‐2,5,8,11‐tetraoxo‐1(12),6(7)‐di(biphenyl)dodecane (TATODBDD) as a neutral carrier. The sensor exhibits a Nernstian response for Pr(III) ions, a wide concentration range of 3.9×10^?7?1.0×10^?1 mol/L with a detection limit of 5.0×10^?8 mol/L and slope of 19.5 mV/decade. The developed sensor revealed relatively good selectivity and high sensitivity for Pr(III) ions over the other lanthanide ions. The potentiometric response of the sensor is independent in the pH range 2.9–9.5. The advantages of sensor are low resistance, very fast response time (<10 s) with good selectivity. This sensor can be used up to 6 weeks without any divergences in potential response.     

Ionic Organic Film Sensor for Determination of Phenolic Compounds

This paper describes the development of a new sensor based on an ionic organic film. The amphiphilic molecule, 4‐[(4‐decyloxyphenyl)‐ethynyl]‐1‐methylpyridinium iodide (10PyI), which has liquid‐crystalline properties, was synthesized and applied in the construction of a GCE/10PyI sensor. Analytical parameters for caffeic acid, repeatability (4.8 %), reproducibility (2.8 %), linearity (two ranges: 9.9×10^?7 to 3.8×10^?5 mol L^?1 and 4.7×10^?5 to 9.9×10^?5 mol L^?1) and detection limits (9.0×10^?7 mol L^?1 and 8.7×10^?6 mol L^?1), were determined. The method was successfully applied in the determination of total phenolic compounds (TPC) in mate herb extracts.     

Flow‐Through Potentiometric Sensors for Alizarin Red S Dye and Their Application for Aluminum Determination

Novel selective and sensitive poly (vinyl chloride) membrane sensors are developed for measuring alizarin red S (AR) based on the use of aliquate 336, Mg^IIphthalocyanine (MgPc), Cu^IIphthalocyanine (CuPc) and Fe^II phthalocyanine (FePc) plasticized poly (vinyl chloride) membrane. The sensors display Nernestian response with slopes of ‐50.6 ± 0.6 , ‐37.4 ± 0.5 , ‐37.7 ± 0.8 and ‐35.0 ± 0.7 mV decade^?1 over the range of 5.2 × 10^?6 to 1 × 10^?2 mol L^?1 for all of them and detection limits of 5.9 × 10^?7, 1.9 × 10‐^?6 2.3 × 10^?6 and 1.9 × 10^?6 mol L^?1 for aliquate, MgPc, CuPc and FePc membrane based sensor, respectively. The sensors exhibit long life span, long term potential stability, high reproducibility, fast response and good discrimination ability towards alizarinate ion in comparison with many other anions. A tubular detector based on aliquate, MgPc, CuPc and FePc was further developed and coupled to a flow‐injection system for alizarin (AR) determination. Under optimized conditions, the linearity range is 1.0 × 10^?5‐ 1.0 × 10^?1 mol L^?1, with a slope of ‐52.1 ± 0.8, 20.9 ± 0.7, 23.6 ± 0.4 and 25 ± 1.1 mV decade^?1 and a reproducibility of ± 0.8 mV (n = 6) for aliquate, MgPc, CuPc and FePc membrane based sensors, respectively. The sensor based on aliquate is further utilized for a potentiodynamic quantification of aluminum in sludge samples and deodorants. The buffered solution of alizarin was allowed to react in a flow system with aluminum. The calibration curve of Al was found to be linear over a concentration range of 0.1 to 1.8 and 1.0 ‐ 40 μg mL^?1 with a slope = 16.9 (r² = 0.993) and 1.76 (r² = 0.994) mV (μg/mL)^?1 and a detection limit of 0.08 and 0.5 μg mL^?1 for 10^?4 and 10^?3 mol L^?1 AR^? as a carrier, respectively. The method was successfully used for determining aluminum in sludge samples and deodorants. The data agree fairly well the nominal values and with results obtain by continuous flow hydride generation inductively coupled plasma (ICP) method.     

Novel Polymeric Membrane Sensors Based on Mn(III) Porphyrin and Co(II) Phthalocyanine Ionophores for Batch and Flow Injection Determination of Azide

Two novel potentiometric azide membrane sensors based on the use of manganese(III)porphyrin [Mn(III)P] and cobalt(II)phthalocyanine [Co(II)Pc] ionophores dispersed in plasticized poly(vinyl chloride) PVC matrix membranes are described. Under batch mode of operation, [Mn(III)P] and [Co(II)Pc] based membrane sensors display near‐ and sub‐Nernstian responses of ?56.3 and ?48.5 mV decade^?1 over the concentration ranges 1.0×10^?2?2.2×10^?5 and 1.0×10^?2?5.1×10^?5 mol L^?1 azide and detection limits of 1.5×10^?5 and 2.5×10^?5 mol L^?1, respectively. Incorporation of both membrane sensors in flow‐through tubular cell offers sensitive detectors for flow injection (FIA) determination of azide. The intrinsic characteristics of the [Mn(III)P] and [Co(II)Pc] based detectors in a low dispersion manifold show calibration slopes of ?51.2 and ?33.5 mV decade^?1 for the concentration ranges of 1.0×10^?5?1.0×10^?2 and 1.0×10^?4?1.0×10^?2 mol L^?1 azide and the detection limits are1.0×10^?5 and 3.1×10^?5 mol L^?1, respectively. The detectors are used for determining azide at an input rate of 40–60 samples per hour. The responses of the sensors are stable within ±0.9 mV for at least 8 weeks and are pH independent in the range of 3.9?6.5. No interferences are caused by most common anions normally associated with azide ion.     

Flow‐Through Assay of Quinine Using Solid Contact Potentiometric Sensors Based on Molecularly Imprinted Polymers

Miniaturized potentiometric membrane sensors for quinine incorporated with molecular imprinted polymer (MIP) were synthesized and implemented. Planar PVC based polymeric membrane sensors containing quinine‐methacrylic and/or acrylic acid‐ethylene glycol methacrylate were dispensed into anisotropically etched wells on polyimide wafers. The determination of quinine was carried out in acidic solution at pH 6, where positively charged species predominated prevalently. The suggested miniaturized planner sensors exhibited marked selectivity, sensitivity, long‐term stability and reproducibility. At their optimum conditions, the sensors displayed wide concentration ranges of 4.0×10^?6–1.0×10^?2mol L^?1 and 1.0×10^?5–1.0×10^?2 mol L^?1 with slopes of about 61.3–55.7 mV decade^?1; respectively. Sensors exhibit detection limits of 1.2×10^?6 and 8.2×10^?6 mol L^?1 upon the use of methacrylic and acrylic acid monomers in the imprinted polymer, respectively. Validation of the assay method according to the quality assurance standards (range, within‐day repeatability, between‐day variability, standard deviation, accuracy, and good performance characteristics) which could assure good reliable novel sensors for quinine estimation was justified. Application of the proposed flow‐through assay method for routine determination of quinine in soft drinks was assayed and the results compared favorably with data obtained by the standard fluorimetric method.     

Catalytic Adsorptive Stripping Voltammetry of Cobalt in the Presence of Nitrite at an In Situ Plated Bismuth Film Electrode

For the first time an in situ plated bismuth film electrode has been applied to catalytic adsorptive stripping voltammetry of cobalt in the presence of nitrite. At optimised conditions bismuth film was plated before each measurement for 30 s at ?1.0 V from a sample solution with the added supporting electrolyte and Bi(III) in the form of its complex with tartrate. The calibration graph for Co(II) for an accumulation time of 120 s was linear from 5×10^?10 to 1×10^?8 mol L^?1. The detection limit was 1.1×10^?10 mol L^?1. The proposed procedure was applied for Co(II) determination in certified water reference material.     

Novel Ytterbium(III) Selective Membrane Sensor Based on N‐(2‐Pyridyl)‐N′‐(2‐Methoxyphenyl)‐Thiourea as an Excellent Carrier and Its Application to Determination of Fluoride in Mouth Wash Preparation Samples

The construction, performance, and applications of a novel ytterbium(III) sensor based on N‐(2‐pyridyl)‐N′‐(2‐methoxyphenyl)‐thiourea (PMT), as an excellent carrier, in plasticized poly(vinyl chloride) PVC matrix, is described. The influences of membrane composition and pH on the potentiometric response of the sensor were investigated. The sensor exhibits a nice Nernstian response for Yb(III) ion over a wide concentration range of 4 decades of concentration (1.0×10^?6–1.0×10^?2 M), and a detection limit of 5.0×10^?7 M. The response time of the electrodes is between 8 and 10 s, depending on the concentration of ytterbium(III) ions. The proposed sensor can be used for about 8 weeks without any considerable divergence in potential. The sensor revealed very good selectivity for Yb(III) in the presence of several metal ions. The best performance was observed for the membrane containing; 30% PVC, 59% o‐nitrophenyloctyl ether (NPOE) as solvent mediator, 7% PMT, and 4% sodium tetraphenyl borate (NaTPB). It was successfully applied as indicator electrodes in the potentiometric titration of Yb(III) with EDTA and for the determination of fluoride ion in two mouth wash formulations. The proposed La(III) sensor was found to work well under laboratory conditions. It was also used as an indicator electrode in titration of a 1.0×10^?4 M of Yb(III) with a standard EDTA solution (1.0×10^?2 M). It was also used for determination of Yb(III) ion in Xenotime .     

Electrochemical Determination of Neurotransmitters at Crown Ether Modified Carbon Nanotube Composite: Application for Sub‐nano‐sensing of Serotonin in Human Serum

We propose an electrochemical sensor based on applying two successive thin layers from a mixture of multiwalled carbon nanotubes‐ionic liquid crystal and crown ether at glassy carbon electrode surface (GC/(CNTs‐ILC)/Crown). The sensor was used for sensitive determination of neurotransmitters based on effective synergism between its components. The compact conducting surface of (CNTs ‐ ILC) with large surface area allowed the assembling of stable host‐guest inclusion complexes between crown ethers and neurotransmitters. The GC/(CNTs‐ILC)/Crown exhibited excellent electro‐catalytic activity toward the determination of serotonin (ST) in a wide linear dynamic range: 0.005 μmol L^?1 to 100 μmol L^?1. In the concentration range 0.005 μmol L^?1 to 1 μmol L^?1, the detection limit is 2.03×10^?10 mol L^?1 and quantification limit is 6.78×10^?10 mol L^?1 with correlation coefficient 0.999. The sensor was successfully applied for ST detection in human serum samples with satisfied recovery results. The sensor showed excellent analytical performance for the determination of ST in terms of low detection limit, good sensitivity and reproducibility. Furthermore excellent anti‐interference ability and simultaneous determination of ST in presence of other compounds as ascorbic acid, dopamine and antidepressant drug were achieved.     

Development of All‐solid‐state Antidiabetic Drug Metformin‐selective Microsensor and its Electrochemical Applications

In this study, all‐solid‐state type potentiometric PVC membrane selective microsensor was developed for Metformin (MET) which is an antidiabetic drug active substance. Metformin‐tetraphenylborate (MET‐TPB) ion‐pair was used as an ionophore in the structure of the sensor membrane. It was determined that the sensor membrane at the ratio of 69 % o‐nitrophenyl octyl ether, 27 % polyvinyl chloride and 4 % MET‐TPB performed the best potentiometric performance. In a wide concentration range (1×10^?5–1×10^?1 mol/L), the slope, detection limit, response time, pH range, and life‐time of the sensor were determined as 55.9±1.6 mV (R²=0.996), 3.35×10^?6 mol/L, 8–10 s, pH: 3–8, and ～10 weeks, respectively. The voltammetric performances of the sensor were also investigated. The prepared microsensor was successfully utilized for the determination of Metformin in a pharmaceutical drug sample by potentiometry and voltammetry. It was observed that the obtained results were in agreement with the results obtained by the UV spectroscopy method at 95 % confidence level.     

Voltammetric Determination of 3‐Nitrofluoranthene and 3‐Aminofluoranthene at Boron Doped Diamond Thin‐Film Electrode

The voltammetric behavior of 3‐nitrofluoranthene and 3‐aminofluoranthene was investigated in mixed methanol‐water solutions by differential pulse voltammetry (DPV) at boron doped diamond thin‐film electrode (BDDE). Optimum conditions have been found for determination of 3‐nitrofluoranthene in the concentration range of 2×10^?8–1×10^?6 mol L^?1, and for determination 3‐aminofluorathnene in the concentration range of 2×10^?7–1×10^?5 mol L^?1, respectively. Limits of determination were 3×10^?8 mol L^?1 (3‐nitrofluoranthene) and 2×10^?7 mol L^?1 (3‐aminofluoranthene).     

Construction and Validation of New Electrochemical Carbon Nanotubes Sensors for Determination of Acebutolol Hydrochloride in Pharmaceuticals and Biological Fluids

A simple, rapid and a highly selective method for direct electrochemical determination of acebutolol hydrochloride (AC) was developed. The developed method was based on the construction of three types of sensors conventional polymer (I), carbon paste (II) and modified carbon nanotubes (MCNTs) carbon paste (III). The fabricated sensors depend mainly on the incorporation of acebutolol hydrochloride with phosphotungstic acid (PTA) forming ion exchange acebutolol‐phosphotungstate (AC‐PT). The performance characteristics of the proposed sensors were studied. The sensors exhibited Nernstian responses (55.6 ± 0.5, 57.14 ± 0.2 and 58.6 ± 0.4 mV mol L^?1) at 25 °C over drug concentration ranges (1.0 × 10^?6‐1.0 × 10^?2, 1.0 × 10^?7‐1.0 × 10^?2 and 5.0 × 10^?8‐1.0 × 10^?2 mol L^?1 with lower detection limits of (5.0 × 10^?7, 5.0 × 10^?8 and 2.5 × 10^?8 mol L^?1 for sensors (I), (II) and (III), respectively. The influence of common and possible interfering species, pharmaceutical additives and some related pharmacological action drugs was investigated using separate solution method and no interference was found. The stability indicating using forced degradation of acebutolol hydrochloride was studied. The standard addition method was used for determination of the investigated drug in its pharmaceutical dosage forms and biological fluids. The results were validated and statistically analysed and compared with those from previously reported methods.     

Efficient Synthesis of a New Podand and Application as a Suitable Carrier for Silver Ion‐Selective Electrode

A new podand of 1,1′‐thia‐bis‐[1‐(chloroethan‐2‐acetamid‐α‐oxy)] naphtol was synthesized and used as a suitable carrier for Ag⁺ PVC membrane electrode. The electrode exhibited linear response with a Nernstian slope of (59.5±0.8 mV/decade) within a wide concentration range of 1.0×10^?7 to 1.5×10^?2 mol L^?1 silver ions. The electrode had a fast response time of <10 s and detection limit of 8.6×10^?8 mol L^?1 with a working pH range from 3.7 to 9.0. The electrode was highly selective for Ag(I) ions over a large number of cations such as alkali, alkaline earth, and heavy metal ions. The proposed sensor has been applied as an indicator electrode for indirect determination of vitamin B₁ in tablets by determination of Cl^? ions in this compound with a standard solution of Ag(NO₃).     

Quantitative Analysis of Holmium Ion by a Ho3+ Ion‐Selective Sensor Based on a Symmetric Thio‐Schiff's Base

A poly(vinyl chloride) (PVC) membrane sensor for holmium ions was fabricated based on N‐[(Z)‐1‐(2‐thienyl)‐ methylidene]‐N‐[4‐(4‐{[(Z)‐1‐(2‐thienyl)methylidene]amino} phenoxy)phenyl] amine (TPA) as a new ion carrier, acetophenon (AP) as plasticizing solvent mediator and sodium tetraphenyl borate (NaTPB) as an anion excluder. The electrode shows a good selectivity towards Ho³⁺ ions respect to other inorganic cations, including alkali, alkaline earth, transition and heavy metal ions. The constructed sensor displays a Nernstian behavior (19.5±0.3 mV/decade) over the concentration range of 1.0×10⁻⁶ to 1.0×10⁻² mol·L⁻¹ with the detection limit of the electrode being 4.6×10⁻⁷ mol·L⁻¹ and very short response time (ca. 5 s). It has a useful working pH range of 3.2–9.8 for at least 8 weeks. The electrode was successfully applied as an indicator electrode for the potentiometric titration of a Ho³⁺ solution with EDTA and holmium determination in some alloys. The proposed sensor accuracy was studied by the determination of Ho³⁺ in mixtures of three different ions.     

Fe(III) Ion‐Selective Membrane Electrode Based on 4‐Amino‐6‐methyl‐3‐methylmercapto‐1,2,4‐triazin‐5‐one

Abstract

An original highly selective and sensitive PVC membrane sensor, working as a Fe(III) ion selective electrode and using 4‐amino‐6‐methyl‐3‐methylmercapto‐1,2,4‐triazin‐5‐one (AMMTO) as an ionophore, has been developed. This cetain sensor demonstrated the following performance; a linear dynamic range between 1.0×10^?6 and 1.0×10^?1 M with a near Nernstian slope of 19.4±0.5 mV per decade; a detection limit of 6.8×10^?7 M; characteristically, the best performance was obtained with a membrane composition of 30% poly(vinyl chloride), 65.5% nitrophenyl octyl ether, 2% sodium tetraphenyl borate and 2.5% AMMTO. Furthermore, the potentiometric response of the developed electrode is independent of the solution pH in the range of 2.2–4.8. The sensor possesses the advantages of short conditioning time, fast response time (<15 s) and, especially, great selectivity towards transition and heavy metal ions and some mono, di‐ and trivalent cations. The electrode can be used for at least 9 weeks without any considerable potential divergence. It was effectively used as an indicator electrode in the potentiometric titration of Fe(III) ions with EDTA and the direct determination of Fe³⁺ in different water samples.     

Nanostructured Hexacyanoferrate Intercalated Ni/Al Layered Double Hydroxide Modified Electrode as a Sensitive Electrochemical Sensor for Paracetamol Determination

An electrochemical sensor for paracetamol (PC) based on the hexacyanoferate(III) intercalated Ni−Al layered double hydroxide (Ni−Al−HCF) was presented. The as‐prepared LDH structurally and morphologically was characterized by scanning electron microscopy, X‐ray diffraction, and Fourier transform IR. Electrochemical studies revealed that Ni−Al−HCF film modified glassy carbon (GC) electrode exhibited remarkable electrocatalytic activity toward the oxidation of paracetamol. The electrochemical behavior of PC on the Ni−Al−HCF film was investigated in detail. Under optimum experimental conditions, the electrocatalytic response of the modified GC electrode was linear in the PC concentration range 3×10⁻⁶⁻–1.5×10⁻³ mol L⁻¹, with a detection limit of 8×10⁻⁷ mol L⁻¹ (S/N=3), using hydrodynamic amperometry. In addition, the modified electrode exhibited good reproducibility, long‐term stability and anti‐interference property. The fabricated sensor was successfully applied to determination of PC in various pharmaceutical preparations such as tablets, oral solution, and oral drops. Finally, the method was validated by the analysis of paracetamol spiked human serum samples, and good recoveries were obtained in the range of 99.2–103 %.     

Direct Determination of Paracetamol in Environmental Samples Using Screen‐printed Carbon/Carbon Nanofibers Sensor – Experimental and Theoretical Studies

The paper describes the first electrochemical method (differential pulse adsorptive stripping voltammetry, DPAdSV) using a screen‐printed sensor with a carbon/carbon nanofibers working electrode (SPCE/CNFs) for the direct determination of low (real) concentrations of paracetamol (PA) in environmental water samples. By applying this sensor together with DPAdSV, two linear PA concentration ranges from 2.0×10^?9 to 5.0×10^?8 mol L^?1 (r=0.9991) and 1.0×10^?7–2.0×10^?6 mol L^?1 ( r=0.9994) were obtained. For the accumulation time of 90 s, the limit of detection was 5.4×10^?10 mol L^?1. Moreover, the SPCE/CNFs sensor and the DPADSV procedure for PA determination are potentially applicable in field analysis. The process of PA adsorption at the SPCE/CNFs surface was investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and theoretical studies. In the theoretical study of the interaction of CNF and PA, the first species was modelled by graphene‐like clusters containing up to 37 rings. It was found that the preferable orientation of PA is parallel to the carbon surface with the binding energy of about ?68 kJ/mol calculated by symmetry‐adapted perturbation theory (SAPT). Both the selectivity and the accuracy of the developed sensor for real sample analysis were also investigated using Polish river and sea samples.     

Ruthenium(III) Schiff's Base Complex as Novel Chloride Selective Membrane Sensor

A novel chloride PVC‐based membrane sensor based on a ruthenium(III) Schiff's base complex, as an excellent neutral carrier, has been developed. The ruthenium complex, in combination with a ketonic plasticizer and a cationic additive led to ISEs with fundamental characteristics, such as slope sensitivity, short response times and selectivity coefficients, which were sufficient for practical applications. The sensor with composition of 30% PVC, 62% benzyl acetate, 5% ruthenium(III) Schiff's base complex and 3% hexadecyltrimethyl ammonium bromide displays near‐Nernstian behavior in a wide concentration range (1.0×10^?1–3.0×10^?6 M with slope of ?54.5±0.5) with a detection limit of 2.0×10^?6 M (71.0 ng per mL). The response of the electrode is independent on pH in the range of 4.0–10.0 and can it be used for at least ten weeks. The proposed electrode shows a very short response time (<20 s) in whole concentration range. The sensor displays high selectivity toward chloride ions over several organic and inorganic anions. It was successfully applied for the determination of chloride in serum samples. It was also used as an indicator electrode in the potentiometric titration of chloride ions with silver nitrate solution.     

Voltammetric Ion‐Selective Nanocomposite Carbon Paste Electrode for Determination of Erbium at the Interface Between two Immiscible Electrolyte Solutions

In this study for the first time a novel erbium(III) voltammetric ion‐selective nanocomposite carbon‐paste electrode was introduced based on the concept of ion transfer at the interface between two immiscible electrolyte solutions. N′‐(2‐hydroxy‐1,2‐diphenylethylidene) benzohydrazide (HDB) was used as a selective ionophore in the composition of the carbon paste. The ionophore facilitates transfer of Er(III) from the aqueous solution to the room temperature ionic liquid (RTIL) phase after reduction of the redox probe to maintain charge neutrality. The plot of the peak potential versus the logarithm of the concentration exhibits a Nernstian response (19.9±0.2 mV decade^?1) toward Er(III) in the range of 7.5×10^?7–1.0×10^?1 mol L^?1 with detection limit of 5.0×10^?7 mol L^?1. The proposed sensor shows a fast response time of about 5 s.