Sodium ion sensors based on dibenzo-16-crown-5 compounds with amide side arms

Abstract

Lipophilic dibenzo-16-crown-5 compounds with amide-containing side arms attached to the central carbon atom of the three-carbon bridge in the polyether ring have been applied as neutral carriers for sodium ion-selective field-effect transistors (Na⁺-ISFET′s). ISFET′s based on these lariat ether amides exhibit excellent Na⁺/K⁺ selectivities (K_Na′K ^Pot = 7 × 10^?3) and Na⁺/H⁺ selectivities (K_Na′H ^Pot = 3 × 10^?3) with good selectivities for Na⁺ over other alkali metal cations and alkaline-earth metal cations. High sensor durability was obtained for these ISFET′s.     

Reference field effect transistors based on chemically modified ISFETs

Different hydrophobic polymers were used for chemical modification of ion-sensitive field effect transistors (ISFETs) in order to prepare a reference FET (REFET). Chemical attachment of the polymer to the ISFET gate results in a long lifetime of the device. Properties of polyacrylate (polyACE) REFETs are described in detail. The polyACE-REFET is superior to other polymer modified REFETs, showing an excellent pH insensitivity (?1 mV pH^?1), a long lifetime and an electrically identical behaviour as an unmodified pH ISFET or a cation-selective PVC-MEMFET (membrane FET). The cation permeselectivity of the polymer can be significantly reduced by addition of immobile cations. The applicability of a polyACE-REFET in differential measurements with a pH ISFET and a K⁺ MEMFET is demonstrated.     

Micro Ammonia Sensor

Abstract

A micro ammonia sensor, consisting of an ISFET covered with a dry membrane which is made from nonactin and substituted poly-γ-methyl-L-glutamate (PMG) is described. The gate output voltage of the micro ammonia sensor increased with NH₄OH addition. The response time of the sensor was 2 min at 30°C, and the sensor exhibited superior selectivity for NH₄ ⁺ compared to a pH sensitive ISFET.     

Ion-selective field effect transistors with polymeric membranes

The construction and operation of ion-selective field effect transistors (ISFET) with polymeric membranes are described, and their electrical and chemical performance are discussed. The H⁺, K⁺, and Ca²⁺ ISFET's all show responses similar to those of the corresponding ion-selective electrodes, with t_95% response times of approximately 40 ms and accurate ion activity measurements for periods up to one month.     

Borazon-gate pH-sensitive field effect transistor

A borazon-gate ISFET is used as a pH sensor. Boron nitride was deposited by the reactive-pulse plasma method and electron diffraction served for membrane identification. The borazon-gate sensors responded linearly to pH in the range 1.8–10; the slope was about 52 mV pH^?1. Selectivity for H⁺ ions over K⁺, Na⁺ or Ca²⁺ ions was better than that of silicon nitride-gate ISFETs.     

Detecting Both Physical and (Bio‐)Chemical Parameters by Means of ISFET Devices

A multi‐parameter sensor system for the detection of eight (bio‐)chemical and physical parameters (pH, potassium concentration, penicillin concentration, diffusion coefficient of H⁺‐ and OH ^–‐ions, temperature, flow velocity, flow direction and liquid level) is realized by using the same transducer principle. A Ta₂O₅‐gate ISFET (ion‐sensitive field‐effect transistor) is applied as basic transducer for all kinds of sensors. The multi‐parameter detection is achieved by means of sequentially or simultaneously scheduling of the hybride sensor modules consisting of four ISFET structures and an ion generator in different sensor arrangements and/or different operation modes. Thus, more parameters (eight) can be detected than the number of sensors (four) in the system.     

Alcohol-FET sensor based on a complex cell membrane enzyme system

An alcohol -FET sensor was developed by use of a complex enzyme system in a cell membrane and an ion-sensitive field effect transistor (ISFET). The cell membrane of Gluconobacter suboxydans IFO 12528, which converts ethanol to acetic acid, was immobilized on the gate of an ISFET with calcium alginate gel coated with nitrocellulose. This ISFET (1), a reference ISFET without the cell membrane (ISFET 2) and an Ag/AgCl reference electrode were placed in 5 mM Trismalate buffer (pH 5.5, 25°C), and the differential output between ISFETS 1 and 2 was measured. The output of the sensor was stabilized by adding pyrroloquinoline quinone. The response time was ca. 10 min., and there was a linear relationship between the differential output voltage and the ethanol concentration up to 20 mg l^?1. The output of the sensor was stable for 40 h below 30°C. The sensor responded to ethanol, propan- 1-ol and butan- 1-ol, but not to methanol, propan-2-ol and butan-2-ol. The sensor was used to determine blood ethanol.     

Development of microbiosensors

Semiconductor fabrication technology was used for development of ion sensitive field effect transistor (ISFET) and micro-electrodes which have been utilized as transducers of enzyme-based microbiosensors. A urea sensor consisted of two ISFETs; one ISFET is urease-coated ISFET and the other ISFET is reference ISFET. A linear relationship was obtained between the initial rate of voltage change and the logarithm of urea concentration over the range 1.3 to 16.7 mM. ATP and hypoxanthine sensors were also developed utilizing ISFET as a transducer. Furthermore, microelectrodes such as hydrogen peroxide and oxygen sensors were prepared by the silicone fabrication technology. A glucose sensor consisted of a hydrogen peroxide electrode and immobilized glucose oxidase membrane. A linear relationship was observed between the current increase and the concentration of glucose (1–100 mg dl⁻¹). A microoxygen electrode was constructed from Au electrodes, polymer matrix containing alkaline electrolyte and a photocross-linkable polymer membrane. This electrode was used as a transducer in microglucose sensor. A microglutamic acid sensor is also described.     

The Potentiometric Biosensor Acetylcholine Esterase as a Model System

 In a methodical investigation of pH-detection systems (glass and polymer membrane electrodes and ion selective field effect transistor (ISFET)), the possible use of the acetylcholine esterase biosensor as a model for all pH-based biosensors is shown. It revealed that the biomembrane properties are more important for the result than the technology itself. All techniques resulted in a ΔH⁺ detection limit of 6*10⁻⁷ mol/L. Received January 20, 2001; accepted December 18, 2001; published online July 15, 2002     

Preparation of Na+-selective electrodes by ion-implantation of lithium and silicon into single-crystal alumina wafer and its application to the production of ISFET

Summary Sodium ion-selective electrodes (Na⁺-ISE) were prepared by implanting Si⁺ and Li⁺ into alumina wafers and their characteristics were investigated. The alumina wafer had a thickness of 100 m and a diameter of 1.40 cm. The ionselective membrane was produced by ion-implanting of Li⁺ and Si⁺ on both sides of a single-crystal alumina wafer. The total doses of Li⁺ and Si⁺ were controlled to be the same, viz. 10¹³–10¹⁵ ions/cm². The ion-implanted alumina wafer with 10¹⁴ or 4×10¹⁴ ions/cm² of Li⁺ and Si⁺ showed better characteristics than the others.The response curves of the 10¹⁴ ions/cm² implanted alumina wafer had a slope of 42 mV/pNa in a concentration range from 1–10^–4mol/l. The full response achieved after about 1 min was reproducible. The proposed idea of producing Na⁺-ISE by ion-implantation technique was applied to functuate the gate surface of the field effect transitor to sodium ion. The sodium ion-sensitive FET (Na⁺-ISFET) prepared by implanting Li⁺ and Al⁺ at a dose of 5×10¹⁴ ions/cm² showed a slope of 30 mV/pNa in a concentration range from 1–10^–4mol/l.

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Herstellung Na⁺-ionenselektiver Elektroden durch Einbau von Lithium und Silicium in Einkristall-Alumniumoxidblättchen und Anwendung zur Erzeugung von ISFET

Zusammenfassung Na⁺-selektive Elektroden wurden durch Einbau von Si⁺ und Li⁺ in Aluminiumoxidblättchen hergestellt und ihre Charakteristiken untersucht. Die Blättchen hatten eine Dicke von 100 m und einen Durchmesser von 1,40 cm. Ebenso wurde die Membran für einen ISFET hergestellt. Die Gesamtmenge von Li⁺ und Si⁺ wurde auf 10¹³–10¹⁵ Ionen/cm² eingestellt, wobei sich bei 10¹⁴ oder 4×10¹⁴ Ionen/cm² die beste Charakteristik ergab.Die Responsekurven der mit 10¹⁴ Ionen/cm² versehenen Aluminiumoxidplättchen hatten eine Neigung von 42 mV/pNa in einem Konzentrationsbereich von 1–10^–4mol/l. Der nach 1 min erhaltene volle Response war reproduzierbar. Die vorgeschlagene Technik wurde zur Einstellung der Gate-Oberfläche des Feldeffekt-Transistors auf Natriumion benutzt. Der Na⁺-sensitive FET (Na⁺-ISFET), der durch Einbau von Li⁺ und Al⁺ mit 5×10¹⁴ Ionen/cm² hergestellt wurde, zeigte eine Neigung der Signalkurve von 30 mV/pNa in einem Bereich von 1–10^–4mol/l.

     

Detection of Explosives Using Field‐Effect Transistors

The gate surfaces of ion‐sensitive field‐effect transistor (ISFET) devices were functionalized with the π‐donor units, 6‐hydroxydopamine ( 1 ) or 4‐aminothiophenol ( 2 ). Concentration of trinitrotoluene, TNT, on the gate via π‐donor‐acceptor interactions yields charge‐transfer complexes that alter the gate potential. This enables the label‐free analysis of TNT with a detection limit corresponding to 1×10^?7 M.     

A new Na+ and K+ carrier from chemically modified monensin studied in human erythrocytes by 23Na nuclear magnetic resonance,K+ atomic absorption and H+ potentiometry

The transporting ability of a new monensin derivative 26-(1,2-diphenyl-1-ethoxy) monensin, highly active against Gram-positive bacteria, was explored with the human erythrocyte model using three technical approaches: ²³Na nuclear magnetic resonance (internal Na⁺), K⁺ atomic absorption (external K⁺) and H⁺ potentiometry (external H⁺) and compared with monensin 1 and 26-(4-chlorophenylurethane) monensin 3 of known transport selectivities for sodium and potassium respectively. Compound 2 proved to be a good carrier for both Na⁺ and K⁺ under our experimental conditions, thus constituting a new type of monensin derivative. The introduction of Li⁺, Rb⁺ or Cs⁺ in the external buffer as a replacement for Na⁺ led us to propose the transport sequence K⁺, Na⁺ ⪢ Rb⁺ > Li⁺ > Cs⁺ for 2.     

Radiosynthesis and biodistribution of <Superscript>99m</Superscript>Tc-tricarbonyl complex of temafloxacin dithiocarbamate: a potential <Emphasis Type="Italic">Streptococci pneumoniae</Emphasis> infection radiotracer

Extraction of microamounts of cesium by nitrobenzene solutions of sodium dicarbollylcobaltate (Na⁺B⁻), potassium dicarbollylcobaltate (K⁺B⁻) and rubidium dicarbollylcobaltate (Rb⁺B⁻) in the presence of polypropylene glycol PPG 425 (L) has been investigated. The equilibrium data have been explained assuming that the complex species ML⁺ (M⁺ = Na⁺, K⁺, Rb⁺, Cs⁺; L = PPG 425) are present in the organic phase. The stability constants of the cationic complex species ML⁺ (M⁺ = Na⁺, K⁺, Rb⁺) in nitrobenzene saturated with water have been determined; they were found to increase in the series of Rb⁺ < K⁺ < Na⁺.     

Characteristics of the hydrogen ion-sensitive field effect transistors with sol-gel-derived lead titanate gate

The sol-gel-derived lead titanate (PbTiO₃) membrane has been successfully applied as a pH sensitive layer to form the PbTiO₃ gate ion-sensitive field-effect transistor (ISFET). There exhibit the excellent quasi-Nernstian response of 56-59 mV pH⁻¹, good surface adsorption and anticorrosion characteristics via the C-V measurement of the EIS structure. At a specific pH concentration, the output and transfer characteristics are very similar to the behaviours of MOSFETs, and the ISFET model can be derived by the modified MOSFET model. As it operated in the nonsaturation region, there exhibits a linear pH response of about 56-59 mV pH⁻¹. On the other hand, as it operated in the saturation region, the pH response and linearity can be controlled by adjusting the V_GS values, e.g. the pH responses of −4.2, −24.8 and −31.3 μA pH⁻¹ and the correlation coefficients of 0.9491, 0.9995 and 0.9996 at V_GS=1, 3 and 5 V can be obtained, respectively. Besides, in order to get the best pH response and the minimized leakage current, the heat treatment temperature of the PbTiO₃ membrane must be limited between 350 and 450 °C.     

Ab-initio calculations of excited rare gas alkali ions

The excimer-like ions formed by combining a rare gas ion with an alkali atom were investigated by an ab initio HF-CI calculation. The resulting four bound excited states¹Σ⁺,¹Π,³Σ⁺ and³Π were subjected to a semiempirical spin orbit (SO)-coupling yielding eight fine structure levels with angular momenta Ω=2, 1(3) and 0(4). For (NeLi)⁺, (NeNa)⁺, (ArLi)⁺, (ArNa)⁺, (ArK)⁺ and (KrLi)⁺ the wavelengths for the five allowed transitions to the ground state were calculated. The results are in close agreement with the experimental results. Also other spectroscopic properties as binding energies, transition moments and vibrational quanta are given.     

Generation and dissociation of oxygen‐ and chloride‐bridged iron(III) and manganese(III) tetraphenylporphyrin dimer ions in the gas phase

Electrospray ionization mass spectrometry (ESI/MS) has allowed the discovery of novel dimer ions emerging from solutions of metalloporphyrin salts and their investigation by collision‐induced dissociation (CID) with N₂ molecules. ESI mass spectra have been recorded for the formation of the oxygen or chloride‐bridged dimer ions [(FeTPP)₂OH]⁺, [(MnTPP)₂OH]⁺, [(FeTPP)₂Cl]⁺ and [(MnTPP)₂Cl]⁺ derived from various solutions of FeTPPCl and MnTPPCl salts. The CID of [(FeTPP)₂OH]⁺ proceeds mainly by neutral loss of (FeTPP)OH to form [FeTPP]⁺ and, to a minor extent, to form the charge‐reversed products. The CID of [(MnTPP)₂OH]⁺ exhibits exclusively the product ion [MnTPP]⁺ by loss of neutral (MnTPP)OH. [(FeTPP)₂Cl]⁺ and [(MnTPP)₂Cl]⁺ dissociate by loss of (Fe/MnTPP)Cl to give rise to [Fe/MnTPP]⁺. [(FeTPP)₂O]⁺ and [(FeTPP)₂OH]⁺ were generated from a solution of the dimer, (FeTPP)₂O. Dissociation of [(FeTPP)₂O]⁺ yields two product ions, [FeTPP]⁺ and [(FeTPP)O]⁺, with higher onsets compared to the equivalent fragments formed from [(FeTPP)₂OH]⁺. Copyright © 2009 John Wiley & Sons, Ltd.     

Thermal activation of methane and ethene by bare MO·+ (M=Ge, Sn, and Pb): a combined theoretical/experimental study

The thermal ion/molecule reactions (IMRs) of the Group 14 metal oxide radical cations MO ^{. +} (M=Ge, Sn, Pb) with methane and ethene were investigated. For the MO ^{. +}/CH₄ couples abstraction of a hydrogen atom to form MOH⁺ and a methyl radical constitutes the sole channel. The nearly barrier‐free process, combined with a large exothermicity as revealed by density functional theory (DFT) calculations, suggests a fast and efficient reaction in agreement with the experiment. For the IMR of MO ^{. +} with ethene, two competitive channels exist: hydrogen‐atom abstraction (HAA) from and oxygen‐atom transfer (OAT) to the organic substrate. The HAA channel, yielding C₂H₃ ^. and MOH⁺ predominates for the GeO ^{. +}/ethene system, while for SnO ^{. +} and PbO ^{. +} the major reaction observed corresponds to the OAT producing M⁺ and C₂H₄O. The DFT‐derived potential‐energy surfaces are consistent with the experimental findings. The behavior of the metal oxide cations towards ethene can be explained in terms of the bond dissociation energies (BDEs) of MO⁺? H and M⁺? O, which define the hydrogen‐atom affinity of MO⁺ and the oxophilicity of M⁺, respectively. Since the differences among the BDEs(MO⁺? H) are rather small and the hydrogen‐atom affinities of the three radical cations MO ^{. +} exceed the BDE(CH₃? H) and BDE(C₂H₃? H), hydrogen‐atom abstraction is possible thermochemically. In contrast, the BDEs(M⁺? O) vary quite substantially; consequently, the OAT channel becomes energetically less favorable for GeO ^{. +} which exhibits the highest oxophilicity among these three group 14 metal ions.     

CAS SCF/CI calculations of potential energy surfaces of He3+ and He2+

Complete active space MC SCF (CAS SCF) calculations followed by second-order configuration interaction (SOCI) calculations are carried out on the potential energy surfaces (bending surface, linear surfaces) of the ²Σ_g⁺ ground state of He₃⁺. The potential minimum for the ²Σ_g⁺ state occurs at a linear geometry with HeHe bond length of 1.248 Å. The binding energy of He₃⁺ with respect to He + He⁺ + He was calculated to be 2.47 eV at the SOCI level. The energy required to dissociate He₃⁺ (²Σ_g⁺) into He₂⁺ (²Σ_u⁺) and He(¹S) is calculated to be 0.14 eV. The same level of SOCI calculations of He₂⁺ yield a D_e value of 2.36 eV.     

An ESR Study of the Radical Cations of Tetrathiafulvalene (TTF) and Electron Donors Containing the TTF Moiety

Hyperfine data and g factors are reported for the radical cations of tetrathiafulvalene (TTF; 1 ) and of its derivatives 2–13 . From the intense satellite spectra of 1 ⁺– 13 ⁺ not only the coupling constants of the ³³S isotopes in the TTF moiety could be determined, but also, in favourable cases, those of the ¹³C isotopes in the central double bond. The former values range from 0.370 ( 8 ⁺) to 0.470 mT ( 4 ⁺) and the latter from 0.255 ( 8 ⁺) to 0.360 mT ( 4 ⁺) in the radical cations of bis(ethylenedithio)-TTF ( 8 ⁺) and tetracyano-TTF ( 4 ⁺). The radical cation of TTF ( 1 ⁺) exhibits intermediate values, 0.425 for the ³³S and 0.285 mT for the ¹³C isotopes. The spin population in 1 ⁺– 13 ⁺ resides, to a large extent, in the central S₂C ? CS₂ part of the π-system. It tends to increase (decrease) by substitution with electron-accepting (donating) groups in the 2,3,6,7-positions of TTF.