共查询到20条相似文献,搜索用时 15 毫秒
1.
Dimethyl-4,4-dimethoxy-5,6,5′,6′-dimethylene dioxy biphenyl-2,2-dicarboxylate (DDB) liver drug is used as a novel ionophore in plasticized poly (vinyl chloride) (PVC) matrix membrane sensors for barium ions. Optimum performance characteristics are displayed by membrane sensor incorporating DDB ionophore, potassium tetrakis(4-chlorophenyl)borate as lipophilic salt, and o-nitrophenyloctyl ether as plasticizer. The sensor exhibits a linear response over the concentration range 10−1-10−5 mol l−1 BaCl2 with a Nernstian slope of 30 mV per decade and high selectivity towards Ba2+ with respect to Li+, Na+, K+, Rb+, NH4+, Mg2+, Ca2+, Sr2+, Mn2+, Co2+, Ni2+, Cd2+, Al3+, La3+, and Ce3+ ions. The sensor response is stable over a wide pH range (4-9) and the lifetime is about 2 months. The proposed sensor is successfully applied to the determination of Ba2+contents of some rocks. 相似文献
2.
Acetylacetone, ethylacetoacetate and salicyldehyde, are reported to form chelates with copper of high stability as compared to other metals. Therefore, PVC based membranes of bis[acetylacetonato] Cu(II) (A), bis[ethylacetoacetate] Cu(II) (B) and bis[salicyldehyde] Cu(II) (C) have been investigated as copper(II) selective sensors. The addition of sodium tetraphenylborate and various plasticizers, viz., DOS, TEHP, DOP, DBP and TBP have been found to substantially improve the performance of the sensors. The membranes of various compositions of the three chelates were investigated and it was found that the best performance was obtained for the membrane of composition A (1%): PVC (33%): TBP (65%): NaTPB (1%). The sensor shows a linear potential response to Cu(II) over wide concentration range 2.0 × 10−6 to 1.0 × 10−1 M (detection limit 0.1 ppm) with Nernstian compliance (29.3 mV decade−1 of activity) between pH 2.6 and 6.0 with a fast response time of 9 s. The potentiometric selectivity coefficient values as determined by match potential method (MPM) indicate excellent selectivity for Cu2+ ions over interfering cations. The sensor exhibits adequate shelf life (3 months) with good reproducibility (S.D. ±0.2 mV). The sensor has been used in the potentiometric titration of Cu2+ with EDTA. The utility of the sensor has been tested by determining copper in vegetable foliar and multivitamin capsule successfully. 相似文献
3.
Chromogenic calix[4]arene derivative was synthesized and tested as an ionophore for potentiometric and optical sensors. Distinct sodium selectivity was observed with this ionophore based, plasticized PVC membranes in potentiometric measurements suggesting their utility for biological applications. Optode membranes exhibited sodium sensitivity in the 5 x 10(-2) -10(-4)M concentration range. The optical sensitivity was improved by the use of an internal, lipophilic base (TDDA). The operation of the optical sensor is in accordance with the ion-exchange theory. 相似文献
4.
Saleh MB 《Fresenius' Journal of Analytical Chemistry》2000,367(6):530-534
Bis(diarylphosphine oxide) naphthalene compounds are used as novel ionophores in plasticized poly(vinyl chloride) matrix membrane sensors for barium ions. The most favorable sensor was 1,2-bis(diethylphenylphosphine oxide)naphthalene containing potassium tetrakis(4-chlorophenyl)borate as lipophilic salt and o-nitrophenyloctyl ether as plasticizer for ion-selective electrode membrane construction. The electrode showed excellent properties. It gave a linear response with a Nernstian slope of 30 mV per decade within the concentration range 10(-1)-10(-5) mol L(-1) BaCl2. The electrode exhibits a high selectivity towards Ba2+ with respect to Li+, Na+, K+, Rb+, Cs+, NH4+, Ag+, Mg2+, Ca2+, Sr2+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Pb2+, Al3+, La3+, and Ce3+ ions. The electrode response was stable over a wide pH range (3-11). The lifetime of the electrode was about 2 months. It was successfully applied to the determination of Ba2+ contents in some rocks. 相似文献
5.
Yasoo Itoh Yoshihisa Ueda Masao Sugawara Masamitsu Kataoka Hitoshi Sato Yoshio Umezawa 《Analytical sciences》2006,22(2):219-223
The effects of nitrogenous synergists on the potentiometric responses to divalent transition metal ions were investigated concerning polymeric liquid membranes containing thenoyltrifluoroacetone (Htta) as an ionophore. The tested synergists were pyridine (py) and 4,4'-dioctyl-2,2'-bipyridyl (C8bpy). The potentiometric responses to metal ions, such as Cd2+, Co2+, Ni2+ and Zn2+, were induced by adding the synergists into the liquid membrane systems. The coexistence of Htta and a synergist was necessary for generating the membrane potential. The tta- anion adsorbed at the liquid membrane/solution interface and the complex formation between the synergist and a given metal ion appeared to participate in preferential uptake of metal ions. 相似文献
6.
A novel series of transition metal complexes have been synthesized from the reaction of 5-((3-(methylthio)-5-(pyridin-4-yl)-4H- 1,2,4-triazol-4-ylamino)melhyl)quinolm-8-ol with transition metal salts.The structures of these compounds have been elucidated by elemental and spectral analysis.Furthermore,compounds were screened for in vitro antimicrobial activity against the representative panel of two Gram-positive and two Gram-negative bacteria and two strains of fungus.The various compounds show potent inhibitory action against test organisms. 相似文献
7.
A novel solid-contact potentiometric sensor for ascorbic acid based on cobalt phthalocyanine nanoparticles (NanoCoPc) as ionophore was fabricated without any need of auxiliary materials (such as membrane matrix, plasticizer, and other additives). The electrode was prepared by simple drop-coating NanoCoPc colloid on the surface of a glassy carbon electrode. A smooth, bright and blue thin film was strongly attached on the surface of the glassy carbon electrode. The electrode showed high selectivity for ascorbic acid, as compared with many common anions. The influences of the amount of NanoCoPc at the electrode surface and pH on the response characteristics of the electrode were investigated. To overcome the instability of the formal potential of the coated wire electrode, a novel electrochemical pretreatment method was proposed for the potentiometric sensor based on redox mechanism. This resulting sensor demonstrates potentiometric response over a wide linear range of ascorbic acid concentration (5.5 × 10−7 to 5.5 × 10−2 M) with a fast response (<15 s), lower detection limit (ca. 1.0 × 10−7 M), and a long-term stability. Furthermore, microsensors based on different conductors (carbon fiber and Cu wire) were also successfully fabricated for the determination of practical samples. 相似文献
8.
Yin Li Zsolt Csók Péter Szuroczki László Kollár László Kiss Sándor Kunsági-Máté 《Analytica chimica acta》2013
A novel ‘three-level’ deepened cavitand featuring a significantly sizable portal has been synthesized and its interaction with some transition metal ions has been investigated in THF/H2O binary solvent using fluorescence quenching technique. The results suggest that among the used transition metal ions including Ag+, Cd2+, Cu2+, Fe3+, Cr3+, Hg2+, La3+, Mn2+, Ni2+, Zn2+ and Co2+, only Fe3+ and Cu2+ show good quenching ability. In order to interpret the quenching mechanism, the Stern–Volmer kinetics, and the presence of both the dynamic and static quenching have been discussed. It was found that the simultaneous presence of the sphere-of-action static quenching and dynamic quenching model agrees very well with the experimental results. The limits of detection for Fe3+ and Cu2+ were found to be 2.1 × 10−6 mol L−1 (3σ) and 3.6 × 10−6 mol L−1 (3σ), respectively. Cations with potential interference, such as K+, Na+, Mg2+, Ca2+, Co2+, La3+ and Mn2+ do not have significant effects on the determinations of Fe3+ and Cu2+. This cavitand can be potentially applied as optical sensor for the detection of Fe3+ and Cu2+. 相似文献
9.
Two novel uranyl PVC matrix membrane sensors responsive to uranyl ion are described. The first sensor incorporates tris(2-ethylhexyl)phosphate (TEHP) as both electroactive material and plasticizer and sodium tetraphenylborate (NaTPB) as an ion discriminator. The sensor displays a rapid and linear response for UO22+ ions over the concentration range 1×10−1–2×10−5 mol l−1 UO22+ with a cationic slope of 25.0±0.2 mV decade−1. The working pH range is 2.8–3.6 and the life span is 4 weeks. The second sensor contains O-(1,2-dihydro-2-oxo-1-pyridyl)-N,N,N′,N′-bis(tetra-methylene)uronium hexafluorophosphate (TPTU) as a sensing material, sodium tetraphenylborate as an ion discriminator and dioctyl phenylphosphonate (DOPP) as a plasticizer. Linear and stable response for 1×10−1–5×10−5 mol l−1 UO22+ with near-Nernstian slope of 27.5±0.2 mV decade−1 are obtained. The working pH range is 2.5–3.5 and the life span of the sensor is 6 weeks. Interference from many inorganic cations is negligible for both sensors. However, interference caused by some ions (e.g. Th4+, Cu2+, Fe3+) is eliminated by a prior ion exchange or solvent extraction step. Direct potentiometric determination of as little as 5 μg ml−1 uranium in aqueous solutions shows an average recovery of 97.2±1.3%. Application for the determination of uranium at levels of 0.01–1 wt.% in naturally occurring and certified ores gives results with good correlation with data obtained by X-ray fluorescence. 相似文献
10.
11.
12.
Gupta VK Arunima N Singhal B Agarwal S 《Combinatorial chemistry & high throughput screening》2011,14(4):284-302
Prime concerns with modern developments are attributed to high level undetected but important biological substances or even toxicants cycled often among individual and populations; which in turn agonizes environmental monitoring, trace-gas detection, water treatment facilities, in vivo detection in biological fluids and other accomplishments. For the detection of such analytes, several analytical devices combined with biological component have been designed with a physiochemical detector component. Here, we essentially focus on drug-based potentiometric membrane sensors known as ion selective electrodes (ISEs). The functionality of ion-selective membrane is quite intricate, challenging, and our understanding is yet to be thrived with more interventions. ISEs have applied explications to enormous variety of analytical inquires as well as informative tools for probing host-guest chemistry. However, expansion of ISEs based applications is aimed to improve the system performance, acquiring enhanced understanding of their response mechanism, and finding new chemical or physical configurations mainly for human welfare. The major strength of ISEs is the precised analytical information, assured by using the ion-selective membrane electrodes used successfully for both in vitro and in vivo assays of pharmaceutical products as well as in clinical analyses. In this review, we attempt to provide a brief prologue to the applicability and advantages of potentiometric sensors in the analysis of pharmaceutically active compounds emphasizing their employment at molecular level for in situ selection of biologically important analytes. 相似文献
13.
E. Doniga 《Fresenius' Journal of Analytical Chemistry》1999,363(1):108-110
An unconventional structure was obtained by extraction of K+ ions with nitrobenzene solution of thiamine metatungstate. This shows that K+ penetration into the organic phase is not an exchange process. The solution of thiamine metatungstate in nitrobenzene acts
as a spacial structure that entraps K+ ions in a molar ratio of 1 : 2. The absence of a chemical reaction between K+ and the metatungstic anion (proved experimentally) and the specificity of the interaction with K+, suggests that the formation of the structure potassium – thiamine metatungstate (KTM) could be controlled by dimensional
criteria. The nitrobenzene solution of KTM shows a remarkable potentiometric selectivity for K+ compared with any other alkaline and alkaline earth cations. The potentiometric K+-selective electrode, based on KTM as ionophore, responds linearly in the range 3.8 × 10–5–1.0 × 10–1 mol/L, with a slope of 56 mV/ decade and a detection limit of 1.2 × 10–5 mol/L. The electrode maintained these response characteristics over a period of more than two months.
Received: 12 May 1998 / Revised: 28 July 1998 / Accepted: 30 July 1998 相似文献
14.
E. Doniga 《Analytical and bioanalytical chemistry》1999,363(1):108-110
An unconventional structure was obtained by extraction of K+ ions with nitrobenzene solution of thiamine metatungstate. This shows that K+ penetration into the organic phase is not an exchange process. The solution of thiamine metatungstate in nitrobenzene acts
as a spacial structure that entraps K+ ions in a molar ratio of 1 : 2. The absence of a chemical reaction between K+ and the metatungstic anion (proved experimentally) and the specificity of the interaction with K+, suggests that the formation of the structure potassium – thiamine metatungstate (KTM) could be controlled by dimensional
criteria. The nitrobenzene solution of KTM shows a remarkable potentiometric selectivity for K+ compared with any other alkaline and alkaline earth cations. The potentiometric K+-selective electrode, based on KTM as ionophore, responds linearly in the range 3.8 × 10–5–1.0 × 10–1 mol/L, with a slope of 56 mV/ decade and a detection limit of 1.2 × 10–5 mol/L. The electrode maintained these response characteristics over a period of more than two months.
Received: 12 May 1998 / Revised: 28 July 1998 / Accepted: 30 July 1998 相似文献
15.
Measurements of dimerization constants (K(d,HR)) and distribution constants (K(D,HR)) of bis(2-ethylhexyl)phosphinic acid (PIA-8) in three kinds of organic diluents were carried out by a potentiometric two-phase titration technique at 298 +/- 0.1 K. Extraction of iron(III), zinc(II), copper(II), manganese(II), cadmium(II), cobalt(II) and nickel(II) by PIA-8 from 1.0 mol dm(-3) ammonium sulfate solution into heptane was investigated as a function of pH and extractant concentration. The data have been analyzed both graphically and numerically to determine the stoichiometry of extracted species and their extraction constants. The extracted metal species were found to be FeR(3) . 2HR for iron(III), ZnR(2) and ZnR(2) . 3HR for zinc(II), CuR(2) . HR and CuR(2) . 5HR for copper(II), MnR(2) . 2HR and MnR(2) . 3HR for manganese(II), CdR(2) . 3HR for cadmium(II), CoR(2) . HR and CoR(2) . 4HR for cobalt(II) and NiR(2) . 3HR and NiR(2) . 6HR for nickel(II), respectively. 相似文献
16.
17.
Summary Nicotinoyl hydrazide, L, complexes of the MLCl2 · n EtOH type [M = manganese(II), iron(ll), cobalt(II), nickel(II) and copper(II); n = 0 or 1], WL2) (NO3)2 [M = cobalt(II) and nickel(II)] and mixed metal complexes such as HgCo2 L2 Cl6 and (NiL2)HgI4 have been prepared and their nature and structure studied by molar conductance, magnetic susceptibility, electronic, e.s.r. and i.r. spectral measurements. Octahedral structures have been proposed for all the complexes except MnLCl2, CoLCl2 and HgCo2 L2 C16 for which tetrahedral geometry is suggested. 相似文献
18.
In this research, new electrodes were prepared by incorporating a new calix[4]arene derivative into a plasticized poly(vinyl chloride) matrix. Calibration plots with Nernstian slopes (29.9 ± 1.1 mV/decade) for vanadyl ion were observed over a linear range of about four decades of concentration (1.0 × 10−5 to 1.0 × 10−1 mol dm−3, at 25 °C). This electrode revealed a lower limit of detection of 3.9 × 10−6 mol dm−3. Conductometric data showed the relatively strong interaction between calix[4]arene and vanadyl ions. The results show that this electrode can be used in acetonitril and methanol media until 10% (v/v) concentration without interference. It has a short response time and can be used for more than two months without any considerable divergence in the potentials. The influence of membrane composition, the pH of the test solution, and the interfering ions on the electrode performance was investigated. The effect of temperature on the electrode response showed that the temperature higher than 50 °C deteriorates the electrode performance. The isothermal temperature coefficient of this electrode amounted to 0.0015 V °C−1. The results of application show that the electrode can be used successfully in present Cr3+ and Fe3+. 相似文献
19.
The thermal behaviour of some heteropolytungstates of the 2:11 series was studied by means of T.G. and D.T.A. measurements, I.R. spectrometry and X-ray powder analysis (DEBYE -SCHERRER method). 相似文献
20.
Maria Demetriou Theodora Krasia‐Christoforou 《Journal of polymer science. Part A, Polymer chemistry》2012,50(1):52-60
The amino‐ and metal‐ion sensing capability of a novel type of well‐defined block copolymers based on 9‐anthrylmethyl methacrylate (AnMMA; hydrophobic, fluorescent) and 2‐(acetoacetoxy)ethyl methacrylate (AEMA; hydrophobic, metal chelating) has been investigated in organic media. AEMAx‐b‐AnMMAy diblock copolymers were prepared for the first time using reversible addition‐fragmentation chain transfer (RAFT) polymerization. All polymers were characterized in terms of molecular weights, polydispersity indices and compositions by size exclusion chromatography and 1H NMR spectroscopy, respectively. The glass transition (Tg) temperatures of the AEMAx and AnMMAx homopolymers and the AEMAx‐b‐AnMMAy diblock copolymers were determined using differential scanning calorimetry. These systems were evaluated toward their ability to act as effective dual chemosensors (i.e., amino‐ and metal‐ion sensors) in an organic solvent (chloroform). More precisely, the fluorescence intensity of both the AnMMAx homopolymers and the AnMMAx‐b‐AEMAy diblock copolymers in solution exhibited a significant decrease in the presence of triethylamine. Moreover, the presence of iron (III) cations were also found to significantly affect the fluorescence signal of the anthracene moieties when those were combined in a block copolymer structure with the AEMA units, due to complex formation occurring between the β‐ketoester groups of the AEMAx segment and the cations. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献