Development of calcium-selective potentiometric electrode using 10,19- Bis[(octadecylcarbamoyl)methoxyacetyl]-1,4,7,13,16-pentaoxa-10,19- diazacycloheneicosane compound as ionophore (original) (raw)
Related papers
Analytical Chemistry, 2004
An all-solid-state calcium-selective electrode was constructed with poly(pyrrole) solid-contact doped with calcium complexing ligand Tiron. The potentiometric response of this sensor can have a linear range down to 10-9 M with a slope close to Nernstian and detection limit equal to 10-9.6. The effects of pH and the activity of the interfering ion in the conditioning solution on the potentiometric behavior of the constructed sensors were examined. Potential stability, reproducibility, and impedance studies were performed. The selectivity of the constructed electrode is better than that of the conventional calcium-selective electrode with internal filling solution of 10-2 M CaCl 2 and comparable to that of the best liquid-contact electrodes.
A new calcium-sensor based on ion-selective conductometric microsensors - membranes and features
Analytical and Bioanalytical Chemistry, 2001
Based on the concept of ion-selective conductometric microsensors (ISCOM) a new calcium sensor was developed and characterized. ISCOM have a single probe, all-solid-state construction and do not need a reference electrode. These sensors are amenable to miniaturization and integration in the true sense of integrated circuit and microsystem technologies. The detection is accomplished by measurement of the bulk conductance G m of a thin polymeric membrane containing an ion-complexing agent, where the magnitude of G m can be related to the content of the primary ion in the analyzed solution. Thin-film platinum electrodes forming an interdigitated electrode are used as the transducer to detect the conductivity of the polymeric membrane. Optimization of the membrane composition was carried out by testing different types of calcium-ionophores, polymers, and plasticizers. The sensor characteristics have been investigated. The limit of detection is about 10-7 mol L-1. The dynamic range is 10-6-10-1 mol L-1 with a response time of less than 5 s. These parameters are comparable to those of corresponding potentiometric calcium selective electrodes (ISE). The Ca 2+-ISCOM demonstrates good practical relevant selectivities against typical interfering ions for biomedical and environmental applications.
The Water Uptake of Plasticized Poly(vinyl chloride) Solid-Contact Calcium-Selective Electrodes
Electroanalysis, 2011
A hyphenated method based on FTIR-ATR and electrochemical impedance spectroscopy has been applied to simultaneously measure the water uptake, changes in the bulk resistance and potential of plasticized poly(vinyl chloride) (PVC) based Ca 2 + -selective coated-wire (CaCWE) and solid-contact electrodes (CaSCISEs). Most of the water uptake of the ion-selective membranes (ISMs) used in both electrode types took place within the first 9 h in 10 À3 M CaCl 2 showing good correlation with the stabilization of the individual electrode potentials. The bulk resistance of the ISMs of the CaCWEs and the CaSCISEs with poly(3-octylthiophene) (POT) as the solid-contact (SC) increased most during the first 18 h in 10 À3 M CaCl 2 . The increase in the resistance was found to be related to the exchange of K + for Ca 2 + in the ISM and the formation of the Ca 2 + -ionophore (ETH 5234) complex having a lower diffusivity than the free K + ions. In contrary to previously published results on silicone rubber based SCISEs and poly(methyl methacrylate):poly(n-decyl methacrylate) membranes containing POT, the plasticized PVC-based CaS-CISEs with POT as the SC had a higher water uptake than the CaCWEs. The CaSCISEs had a detection limit of 2 10 À8 M Ca 2 + and a good potential reproducibility of 148.9 AE 1.0 mV in 10 À4 M CaCl 2 .
Development of a solid-state thick film calcium ion-selective electrode
Sensors and Actuators B: Chemical, 2003
A solid-state calcium ion-selective electrode was developed using thick film metallization process. Silicone rubber or photoresist was combined with ionophore (ETH 129) forming calcium ion-selective membrane which was coated onto different surfaces of electrode. Super-Nernstian equilibrium relationship between the phase boundary potentials and calcium ion concentrations was observed in the silicone rubber-based membrane that was doped with 10 −7 M CaCl 2 treated montmorillonite. This equilibrium relationship was eliminated when the membrane was doped with 0.1 M CaCl 2 treated montmorillonite. The use of photoresist simplified the manufacturing process for the membrane. The memory effect of the silicone rubber-based membrane could be eliminated when the membrane was conditioned with 0.1 M CaCl 2 . The response time of the electrode with silicone rubber and montmorillonite modified silicone rubber were less than 20 s and the one with photoresist was less than 3 min. The sensitivity of these calcium ion-selective electrodes were around 30 mV per decade, and the selectivity were in the rang from −2.9 to −3.8 for Na + , K + and Mg 2+ ions based on fixed primary ion method (FPIM).
Analytica Chimica Acta, 2001
A new Ca 2+ -selective polyaniline (PANI)-based membrane material suitable for all-solid-state sensor applications is presented. The membrane consists of electrically conducting PANI, bis[4-(1,1,3,3-tetramethylbutyl)phenyl]phosphoric acid (DTMBP-PO 4 H), dioctyl phenylphosphonate (DOPP) and cationic (tridodecylmethylammonium chloride, TDMACl) or anionic (potassium tetrakis(4-chlorophenyl)borate, KTpClPB) lipophilic additives. PANI transforms the ionic response to an electronic signal and functions at the same time as the membrane matrix. PANI is made soluble in dichloro methane (DCM) with the Ca 2+ -selective DTMBP-PO 4 H ligand and membranes can easily be prepared by drop-casting on glassy carbon (GC) substrates. PANI membranes with three different plasticizer (z) and additive (s) contents were studied (the molar ratios between the plasticizer or additive and DTMBP-PO 4 H are denoted as z and s, respectively). The best electrode performance, considering sensitivity and selectivity, was obtained for PANI membranes prepared with z = 0.90 and s = 0.10, containing KTpClPB as ionic additive. The Ca 2+ -sensitivity of this membrane was 27.8 ± 0.2 mV/log a Ca 2+ (10 −1 to 10 −4 M CaCl 2 , LOD = 8 × 10 −7 M) in 0.1 M NaCl, and the selectivity coefficients (log K pot Ca,j ) towards j = Na + , K + , Li + , NH 4 + and Mg 2+ , determined with the fixed interference method, were −3.9 ± 0.1, −4.0 ± 0.1, −3.5 ± 0.1, −3.5 ± 0.1 and −3.6 ± 0.1, respectively. On the other hand, practically no redox or pH sensitivity was observed when TDMACl was used as the ionic additive. The PANI membranes were characterized with potentiometry, electrochemical impedance spectroscopy (EIS) and UV-VIS. : S 0 0 0 3 -2 6 7 0 ( 0 1 ) 0 0 9 9 6 -5
Talanta, 2000
This paper shows the application of conducting polymers (CPs) for constructing potentiometric indicator electrodes. Two types of polypyrrole (PPy)-based calcium sensors are presented, one sensor with PPy-calcion film as the active part and the other sensor with PPy-calcion as a solid-state contact coated with a conventional membrane selective towards calcium ions. It is shown that the PPy-calcion film, due to the complexing properties of calcion ensuring high loading of the film with calcium, is sufficiently selective to be used as the active part or as a mediating layer of the indicator electrode. The electrode, with PPy-calcion film as the active part, was used as the indicator electrode in potentiometric titrations of calcium in mixed solvents, where conventional PVC-based electrode can not be used. For the first time, the practical applicability of PPy-based electrodes in titrations is demonstrated.
Physicochemical Problems of Mineral Processing, 2019
The potential creating properties of a group of acidic chelating compounds are presented. The studies have been carried out by the constructing of new ion-selective electrodes based on PVC membranes doped with the studied compounds, and determining the basic analytical parameters of the electrodes. The usefulness of eight out of nine investigated compounds in the preparation of the membrane phase electrodes selective for cobalt, zinc and cadmium has been shown. It has been also found that the acidic properties of ionophore have an essential influence on the analytical parameters of the constructed electrodes. The response mechanism of the obtained electrodes has been investigated by simultaneous spectrophotometric-potentiometric measurement of membranes used in electrodes. It has been found that during the conditioning of electrode, a complex of active substance with primary ion is formed in the membrane phase, then the membrane composition is established and remains unchanged in the next measurements.
The fabrication of potentiometric membrane sensors and their applications
2010
Abstract Ionophore-incorporated PVC-membrane sensors are well-established analytical tools routinely used for the selective and direct measurement of a wide variety of different ions in complex biological and environmental samples. The key ingredient of such plasticized PVC-members is the involved ionophore, defining the selectivity of the electrodes complex formation with the cation of interest. In the past few years, the development of new ion-selective electrodes for various ions has been reported in
Fresenius' Journal of Analytical Chemistry
A plasticized poly (vinyl chloride) (PVC) membrane electrode sensitive to dodecylbenzenesulfonate (DBS) ion is applied to the determination of anionic polyelectrolytes such as potassium poly (vinyl sulfate) (PVSK) by potentiometric titration, using a poly (diallyldimethylammonium chloride) (Cat-floc) solution as a titrant. The end-point of the titration is detected as the potential jump of the plasticized PVC membrane electrode caused by decrease in the concentration of DBS ion added to the sample solution as a marker ion, due to the ion association reaction between the DBS ion and Cat-floc. The effects of the concentration of DBS ion, coexisting surfactants and electrolytes in the sample solution and pH of the sample on the degree of the potential jump at the end-point were examined. A linear relationship between the concentration of anionic polyelectrolyte and the end-point volume of the titrant exists in the concentration range from 2 × 10-5 to 4 × 10-4 N for PVSK, alginate, and carrageenan.