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ABSTRACT: A series of novel cationic fullerene (C60) derivatives, bearing substituted s-triazine moiety as a side arm, synthesized by using the 1,3 dipolar cycloaddition reaction of C60 with azomethine ylides generated from the corresponding Schiff bases of substituted s-triazine is reported. All the synthesized compounds were characterized by elemental analysis, FT-IR, 1H NMR, 13C NMR and ESI-MS. The compounds 7a, 7d, 7e and 7f cleaved the supercoiled pBR322 DNA into nicked form efficiently upon visible light irradiation in the presence of NADH. The photoinduced superoxide radical and hydroxyl radical generated may act as molecular species causing the DNA scission. Further, the interaction of synthesized molecules with pBR322 plasmid DNA was investigated using computational approaches.
RSC Advances 05/2013;
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ABSTRACT: The present work reports a series of novel cationic fullerene derivatives bearing a substituted-quinazolinone moiety as a side arm. Fullerene-quinazolinone conjugates synthesized using the 1,3-dipolar cycloaddition reaction of C60 with azomethine ylides generated from the corresponding Schiff bases of substituted quinazolinone were characterized by elemental analysis, FT-IR, (1)H NMR, (13)C NMR and ESI-MS and screened for their antibacterial activity against Mycobacterium tuberculosis (H 37 Rv strain). All the compounds exhibited significant activity with the most effective having MIC in the range of 1.562-3.125 μg/mL. Compound 9f exhibited good biological activity compared to standard drugs. We developed a computational strategy based on the modeled M. tuberculosis hypoxanthine-guanine phosphoribosyltransferase (HGPRT) using homology modeling techniques and studied its binding pattern with synthesized fullerene derivatives. We then explored the surface geometry of the protein to place the cage adjacent to the active site while optimizing its quinazolinone side arm to establish H bonding with active site residues.
Journal of Molecular Modeling 04/2013; · 1.80 Impact Factor
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ABSTRACT: We developed a new, advanced, simple and non enzymatic approach for the colorimetric detection of glucose based on calix[4]arene/phenyl boronic acid (CX-PBA)functionalized gold nanoparticles (AuNPs). This molecular receptor proficiently and selectively recognizes glucose due to its ability to reversibly bind diol-containing compounds. The assembly was characterized by transmission electron micrograph (TEM), dynamic light scattering (DLS), UV-Vis, FT-IR, ESI-MS and 1H NMR spectrometry, which demonstrates the binding affinity for glucose via a boronic acid-diol interaction. The linear range for glucose was found to be 5-100 nM with phosphate buffer pH 10, with a lower detection limit of 4.3 nM. Interference by other saccharides was negligible. The biosensor has been successfully applied to estimate the glucose in human blood serum samples and the results compared well to an automatic analyzer. With the advantages of high sensitivity, selectivity and low sample volume, this method is potentially suitable for the on-site monitoring of glucose.
The Analyst 03/2013; · 4.23 Impact Factor
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ABSTRACT: A novel PET with ICT based substituted calix[4]arene fluroionophore was synthesized and used for detection of Cu2+ and F- by emission spectra. The detection limit of the synthesized receptor was found to be 4.16 nM for Cu2+ and 2.15 nM for F-. Moreover, this probe has been applied for recognition of Cu2+ in blood serum and F- from waste water.
The Analyst 03/2013; · 4.23 Impact Factor
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ABSTRACT: A novel PET (photoinduced electron transfer) based substituted calix[4]arene fluoroionophore has been synthesized and used for the selective recognition of Cd2+ and Sr2+ by emission spectra. The detection limit of the synthesized receptor was found to be 0.94 pM for Cd2+ and 1.04 pM for Sr2+. Moreover, this probe has been applied to the recognition of Cd2+ and Sr2+ in waste water.
The Analyst 03/2013; · 4.23 Impact Factor
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ABSTRACT: A series of novel cationic fullerene derivatives bearing a substituted-quinazolin-4(3H)-one moiety as a side arm were synthesized using the 1,3-dipolar cycloaddition reaction of C(60) with azomethine ylides generated from the corresponding Schiff bases of substituted quinazolinones. The synthesized compounds 5a-f were characterized by elemental analysis, FT-IR, (1) H NMR, (13) C NMR, and ESI-MS and screened for their antibacterial activity against Mycobacterium tuberculosis (H(37) RV) and antimicrobial activity against selected Gram-positive (Staphylococcus aureus and S. pyogenes) and Gram-negative (Pseudomonas aeruginosa, Klebsiella pneumonia and Escherichia coli) bacterial and fungal strains (Candida albicans, Aspergillus clavatus, and A. niger), respectively. All the compounds exhibited significant activity, with the most effective compounds having MIC values and zones of inhibition comparable to those of standard drugs.
Archiv der Pharmazie 01/2013; · 1.71 Impact Factor
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ABSTRACT: Novel basket-shaped molecules having calix[4]arene as central rigid core possessing azomaterial in outer space unit in the lengthening arm were synthesised and characterised by elemental analysis and different spectroscopic methods such as Fourier Transform Infrared (FT-IR), electron spin ionization (ESI)-MASS, 1H nuclear magnetic resonance (NMR) and 13C NMR. Mesomorphism behaviour of novel materials was studied using optical polarising microscopy, differential scanning calorimetry and higher-temperature powder X-ray diffraction method to confirm smectic C phase. In most of the compounds, we found rod-like mosaic texture and focal conic textures of smectic C phases. Nematic phases were also quite often found in materials during cooling and heating stage from isotropic phases. The dielectric measurements have been carried out for the determination of real and imaginary parts of the permittivity of the newly designed scaffolds. These studies will give adequate prospects in the field of supramolecular sys
Liquid Crystals 12/2012; · 1.86 Impact Factor
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ABSTRACT: A novel structurally simple calix[4]arene appended 8-amidoquinoline linked conjugate was synthesized and has been used as a turn-on fluorescence probe for Zn(2+) and turn off fluorescence probe for F(-). Moreover, this probe has been applied for Zn(2+) detection in blood serum upto 8.7 μM and fluoride detection upto 22 nM in waste water samples, using emission spectra.
The Analyst 10/2012; · 4.23 Impact Factor
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ABSTRACT: In this communication we report a p-sulfonatocalix[4]arene coated ZnS quantum dots "cup type" highly stable optical probe for the detection and determination of menadione (VK(3)) with high sensitivity and selectivity. The detection of VK(3) depends on supramolecular host-guest chemistry.
The Analyst 08/2012; 137(20):4647-50. · 4.23 Impact Factor
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ABSTRACT: A novel dithio derivatized macrotricyclic compound (cryptand) has been synthesized using high dilution technique by condensation
of diaminodibenzo18-crown-6 with 2, 2′dithiobenzoyl chloride. The compound was characterized by elemental analysis, 1H NMR, 13C NMR and FAB-MS. PVC membrane electrode based on this macrotricyclic compound showed good selectivity for Hg2+ ion with a wide linear range of 1.0×10−6 to 1.0×10−1M and a lower detection limit of 5.0×10−6M with a calibration slope of 30.2mVdecade−1. The electrode response was stable in pH range 3–6. Electrode showed good selectivity for Hg2+ over other interfering metal ions. The electrode was then applied to direct determination of Hg2+ in water samples.
Journal of Inclusion Phenomena 04/2012; 64(1):101-108. · 1.89 Impact Factor
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ABSTRACT: As a part of our investigations to unfold the chemistry of calixresorcinarene, we have focused on the formation of inclusion
complex of a poorly soluble (43μgml−1 at pH 7) drug mycophenolate mofetil (MMF) an immunosuppressive agent and an inosine monophosphate dehydrogenase (IMPDH) inhibitor
with para sulphonatocalix[4]resorcinarene (PSC4R). The complete complexation of the drug was achieved after 48h of stirring
with para sulphonatocalix[4]resorcinarene(PSC[4]R) in water and evaporation of water yield the solid complex. The interaction
between para sulphonatocalix[4]resorcinarene(PSC[4]R) and MMF in solid state inclusion complexes was accomplished by aqueous
phase solubility studies, Thermal Analysis, HPLC, PXRD, FT-IR, and UV–Vis spectroscopy. The results of the phase solubility
experiments are in good conformity to signify the formation of 2:1 PSC4R: MMF complexes. The purpose of this study was to
enhance solubility and resulting in high dissolution rate and bioavailability of this essentially water insoluble drug. The
results of the in vivo study shows that there is a remarkable change in the toxicity of the pure drug MMF and complex did
not produce any mortality up to 2200mgkg−1.
KeywordsPara sulphonatocalix[4]resorcinarene–MMF–Phase solubility study–Invitro release–Acute toxicity–Inclusion complex
Journal of Inclusion Phenomena 04/2012; 70(1):121-128. · 1.89 Impact Factor
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ABSTRACT: A highly selective PVC membrane electrode was prepared for thiocyanate (SCN−) determination, based on macrotricyclic binuclear Cu(II)–Schiff base complex as an ionophore. The novel macrotricyclic compound
(cryptand) was synthesized by condensation of 4,4′-diamino-dibenzo-18-crown-6 with bis(4-formyl phenyl)terephthalate under
high-dilution condition and the structure was confirmed by FT-IR, 1H NMR,13C NMR and MS studies. The Cu(II) complex of the compound was prepared and was examined for use as anion-selective electrode
as a carrier which displays an anti-Hofmeister selectivity sequence in following order: SCN−>ClO4
−>NO3
−>CN−>I−>CO3
2−>NO2
−>Br−>Cl−>SO4
2− with a preference for thiocyanate ion over many common anions. The electrode has a linear dynamic range between 1.0×10−7 and 1.0×10−1M, with a Nernstian slope of −58.9mV decade−1 and detection limit of 3.1×10−8M. The working pH range of the sensor was found be in the range of 3.0–8.0. It exhibits a fast response time of 20s and
has a lifetime of about 2months. Application of the electrode for determination of thiocyanate in waste water samples and
in human urine samples have also been demonstrated.
Journal of Inclusion Phenomena 04/2012; 64(3):239-247. · 1.89 Impact Factor
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ABSTRACT: A simple, rapid, cost effective and extractive UV spectrophotometric method was developed for the determination of Gemcitabine HCl (GMCT) in bulk drug and pharmaceutical formulation. It was based on UV spectrophotometric measurements in which the drug reacts with gold nanoparticles (AuNP) and changes the original colour of AuNP and forms a dark blue coloured solution which exhibits absorption maximum at 688nm. The apparent molar absorptivity and Sandell's sensitivity coefficient were found to be 3.95×10(-5)lmol(-1)cm(-1) and 0.060μgcm(-2) respectively. Beer's law was obeyed in the concentration range of 2.0-40μgml(-1). This method was tested and validated for various parameters according to ICH guidelines. The proposed method was successfully applied for the determination of GMCT in pharmaceutical formulation (parental formulation). The results demonstrated that the procedure is accurate, precise and reproducible (relative standard deviation <2%). As it is simple, cheap and less time consuming, it can be suitably applied for the estimation of GMCT in dosage forms.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 03/2012; 94:235-42. · 2.10 Impact Factor
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ABSTRACT: In the present investigation, we describe some novel calixarene based heterocyclic compounds (5a-5i) in which 1,3,4-oxadiazole and 1,3,4-thiadiazole derivatives have been coupled with 5,11,17,23-tetra-tert-butyl-25,27-bis(chlorocarbonyl-methoxy)-26,28-dihydroxy calix[4]arene. All the newly synthesized calixarene based heterocyclic compounds have been characterized by elemental analysis and various spectroscopic methods like FTIR, (1)H NMR, (13)C NMR, and FAB-MS. All the final scaffolds have been subjected to antioxidant activity, in vitro antimicrobial screening against two gram (+ve) bacteria (S. aureus, S. pyogenes), two gram (-ve) bacteria (E. coli, P. aeruginosa) and two fungal strains (C. albicans, A. clavatus) and also have been screened for their antitubercular activity against Mycobacterium tuberculosis H(37)Rv.
Organic & Biomolecular Chemistry 02/2012; 10(9):1785-94. · 3.70 Impact Factor
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ABSTRACT: A high concern for human health and safety has motivated dynamic research on the potential impact of transition metal ions and their toxic effects, thus it is very challenging to design transition-metal ion detection devices that are cost-effective, rapid and applicable to the biological milieus. Driven by the need to detect trace amounts of Fe 3+ from blood samples, we report a highly selective and ultrasensitive calix[4]arene modified silver nanoprobe for Fe 3+ recognition at the 9.4 nM level from aqueous solution with excellent discrimination against other heavy metals and biomolecules. The assembly was characterized by TEM (transmission electron microscopy), DLS (dynamic light scattering), UV-Vis, FT-IR, ESI-MS and 1 H NMR spectrometry, which demonstrate the higher binding affinity for Fe 3+ . The biosensor has been successfully applied to estimate the ferric ion in human blood serum as well as in human hemoglobin.
Nanoscale 01/2012; · 5.91 Impact Factor
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ABSTRACT: In this communication we report a p-sulfonatocalix[4]arene coated ZnS quantum dots ''cup type'' highly stable optical probe for the detection and determination of menadione (VK 3) with high sensi-tivity and selectivity. The detection of VK 3 depends on supramo-lecular host–guest chemistry. Vitamin K 3 (VK 3) is a synthetic fat soluble vitamin and is used for blood coagulation and in the bone mineralization process. 1 In recent years, it has drawn huge attention due to its remarkable anticancer properties. 2 VK 3 contains a naphthoquinone ring, and its basic structure is 2-methyl-1,4-naphthoquinone. These vitamins are named according to their side chains by forming new derivatives. VK 3 is obtained synthetically without a side chain and is named menadione. The physiological activity of VK 3 is the strongest among the K group vitamins. It shows antitumor and anti-inflammatory activity because of the quinone group in its structure. In a series of in vitro and in vivo animal studies, VK 3 showed significant antineoplastic activities against both malignant cell lines and a variety of human tumor cells. 2 There are several methods reported for the detection and deter-mination of VK 3 such as spectrophotometric, electrochemical, colorimetric reaction, etc. 3 which are frequently used although these approaches are time consuming, laborious, expensive and less sensi-tive. It is crucial to develop sensitive and rapid analytical methods for the estimation of VK 3 due to its wide use in chemical, biological and pharmaceutical areas. Herein we report for the first time the trace level detection of VK 3 using a nanosensor. Supramolecular based nanosensors are an upcoming research area for recognition of biomolecules, organic molecules and metals. Crown and b-cyclodextrin coated nanoparticles (NPs) have already been reported as optical sensors for metal and polycyclic aromatic hydrocarbons (PAHs). 4 Calixarenes are the third generation of host molecules and effective sensing probes for the detection of ions and neutral molecules due to their low toxicity and have excellent complexation ability. 5 Our research group has reported earlier sensitive sensors for ions such as K + and sulphide as well as biomolecules like amino acids. 6 Recently, many calixarenes coated semiconductor NPs were reported as fluorescent sensors of metals, pesticides, amino acids, organic molecules and neurotransmitters. 7 Calixarene-quantum dot systems have been developed as stable fluorescent chemosensors for biomolecules recognition. Quantum dots (QDs) have an exclusive size dependent optical property. This property has made them a powerful molecular recognition tool compared to the traditional organic dyes. There are many biological and metal sensors developed based on fluorescence changes of QDs, induced by chemical modification. 8 ZnSQDs have a wide band gap at room temperature, high index of refraction and high transmittance in the visible range. 9 Due to these properties ZnSQDs have been used widely as an important phosphor for photo-luminescence, electroluminescence and cathodoluminescence. ZnSQDs can be synthesized in an aqueous medium, and they are less expensive and least toxic than any other semiconductor QDs with good photocatalytic properties and hence were found suitable for biological and medical applications. Recently, some reports have been published in which ZnSQDs are used as chemical and biosensors. 10 In this communication we synthesized ZnSQDs by a soft chemical method as reported by M. Chatterjee et al. 11 with some modifications (ESI). The resulting ZnSQDs were capped with poly vinyl-pyrrolidone (PVP) molecules by a co-ordinate bond between the nitrogen of PVP and Zn 2+ . The optical property of NPs increased and was secured for a long time by the coating of p-sulfonatocalix[n] arene. 12 Herein, we used p-sulfonatocalix[4]arene (pSC[4]A) as the surface-coating agent for the PVP capped ZnSQDs to enhance and preserve its optical properties. pSC[4]A was prepared according to a method reported earlier. 13 pSC[4]A coated ZnSQDs were prepared by mixing ZnSQDs with pSC[4]A in tetrahydrofuran at room temperature (ESI). FT-IR spectra of pure pSC[4]A reveal the characteristic peak of the calix moiety at 1430 cm À1 (benzene ring stretching); 2840, 2910 cm À1 (CH 2); 690, 810 cm À1 (aromatic ring); 3422 cm À1 (OH) which are also observed in pSC[4]A–ZnSQDs with minor changes (Fig. S1, ESI). Comparing both spectra, a significant variation has been observed; the peak intensity of –OH found in pure pSC[4]A reduces in pSC[4]A–ZnSQDs. This result clearly indicates that the –OH group of the lower edge of pSC[4]A interacts with PVP capped ZnSQDs and forms a hydrogen bond (O/H/O) during the coating process and a ''cup like'' assembly. 14 Fig. 1(A) shows the fluorescence (FL) spectra of ZnSQDs and p-SC[4]A coated ZnSQDs. It reveals that emission properties of ZnSQDs increased with a small shift towards longer wavelength (red shift, 2 nm: 480 / 482 nm) in the presence of pSC[4]A. Under the
The Analyst 01/2012; 137:4647. · 4.23 Impact Factor
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ABSTRACT: A novel structurally simple calix[4]arene appended 8-amidoquino-line linked conjugate was synthesized and has been used as a turn-on fluorescence probe for Zn 2+ and turn off fluorescence probe for F À . Moreover, this probe has been applied for Zn 2+ detection in blood serum upto 8.7 mM and fluoride detection upto 22 nM in waste water samples, using emission spectra. Zinc ions have received a great deal of attention due to their critical role in the control of gene transcription, metallo enzyme function among all of the biologically important metals and it is the second most abundant transition metal ion in the human body after iron. 1 Zn 2+ is obligatory for human growth and development as human serum contains around 19 mM. Deficiency of Zn 2+ may lead to many diseases ranging from Alzheimer's disease to prostate cancer and diabetes. 2 It is a challenging issue for chemists to develop a chemo-sensor that can distinguish Zn 2+ from Cd 2+ because of the fact that cadmium and zinc are in the same group of the periodic table and have similar properties. Thus, it is essential to design a sensitive chemosensor which can selectively and sensitively detect Zn 2+ in the presence of other cations which also has become a target research area for chemists. Fluoride ions have caused intense concern owing to their imper-ative clinical role as well as their role in the treatment of osteoporosis. Excess fluoride leads to dental and skeletal fluorosis, bone diseases, mottling of teeth, lesions of the thyroid, liver and other organs. 3 There are 15 states in India which are affected by fluorosis and among them Gujarat is the most severely affected state due to high fluoride content in drinking water. 4 And hence, there is an urgent necessity to develop a sensor for fluoride ions having low detection limit as well as high selectivity. The development of fluorescence sensors for detection of cations and anions is a well-established area in modern chemistry because of their immense analytical application in many areas including biology and chemistry. This technique is widely used for recognition of cations and anions due to its distinct advantages in terms of sensi-tivity, selectivity, response time and in situ monitoring. 5 This route of detection embroils an ion recognition unit (ionophore) which is linked to a fluorophore whose photophysical properties are inter-rupted during the recognition process, producing luminescent emis-sion. The design of the fluoroionophore is crucial to this technique and requires a high number of aromatic fluorophores in close proximity to create van der Waals contact and p–p stacking. Under these conditions, electronic excitation of one ring can cause an enhanced interaction with its neighbour, leading to what is termed as an excited-state dimer or an excimer for a fluoroionophore. 6 There have been so many reports on highly p-delocalized planar systems such as pyrene, quinoline, coumarine, antharcene and dansyl chloride which have been used for this purpose. 7 Quinoline 8 and its deriva-tives, particularly 8-hydroxyquinoline and 8-aminoquinoline, are conventional fluorogenic chelators for Zn 2+ . Extensive research has been done on quinoline analogues for fluorescence sensing of tran-sition metal ions. During the last decade we have witnessed the immense involvement of calix[4]arene in innumerable fields. Calix[4] arene based chemosensors have attracted a great deal of attention due to their ability to visually sense analytes with high sensitivity as well as fast response time. 9 Calix[4]arene conjugates linked to an amide group have been used as crucial tools for the detection of a highly electronegative halogen F À , via hydrogen bonding, as well as ketone group and nitrogen atom for Zn 2+ detection by the fluorescence technique. 10 The mechanism of fluorescence involved in the calix[4] arene system is mainly PET, 11 FRET, 12 PCT 13 and ICT 14 used for molecular recognition. Few research articles on quinoline based conjugation with calix[4]arene for emission studies have been repor-ted. 10e Earlier our group has reported cooperative anion recognition by a novel heteroditopic receptor based on dibenzo[18]crown-6 fullero-bis(pyrrolidine) by fluorimetry and a novel nano-aggregation detection technique of TNT using selective and ultrasensitive nano-curcumin as a probe. 15 The outcome of these research works moti-vated us to develop a fluorescence sensor based on lower rim substituted calix[4]arene for the detection of ions. Herein, we propose an easy, sensitive and selective method, with a low detection limit and fast response time, to synthesize fluorescence
The Analyst 01/2012; 137:5491. · 4.23 Impact Factor
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ABSTRACT: a b s t r a c t An advanced and proficient colorimetric sulfide sensor based on gold nanoparticles (AuNP) modified calix[n]arene assembly has been designed and synthesized by generation of strongly binding dithiocar-bamate(DTC). This molecular receptor competently and selectively recognizes sulfide ion via H-bonds. The assembly was characterized by TEM, DLS, UV–vis, FT-IR and 1 H NMR spectrometry which demon-strates the higher binding affinity for sulfide via hydrogen bonding. The optimum range for determination of sulfide is from pH 7 to 10. The lower detection limit is found to be 10 nM. This method is simple and rel-atively free from interference of closely associated ions and is successfully applied to the determination of sulfide in real samples of spiked water and leather waste water.
Sensors and Actuators 01/2012; 168:54-61.
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ABSTRACT: We report ultrasensitive ligand to metal charge transfer (LMCT) based thioctic acid modified gold nanoparticles for the detection of lanthanum ion with excellent sensitivity (50 nM) and selectivity over other cations.
Analytical methods 01/2012; 4(10):3102-3106. · 1.55 Impact Factor
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ABSTRACT: A highly selective and sensitive PVC membrane, containing phenylurea substituted calix[4]arene was found to be a suitable ionophore for monohydrogen phosphate (HPO(4)(2-)) ions that exhibited a Nernstian response (with a slope of -29.4 ± 0.3 mV decade(-1)). The working concentration range of the electrode was 6.0 × 10(-8)-1.0 × 10(-1) mol L(-1) with a detection limit of 2.0 × 10(-8) mol L(-1). The response time of the sensor in the whole concentration range is very short (<8s), with a considerable lifetime of at least 15 weeks. The sensor possesses the advantages of short response time, low detection limit and a high selectivity towards a large number of inorganic anions. The developed sensor was used as an indicator electrode in potentiometric titration of monohydrogen phosphate ion with barium chloride. The proposed sensor was successfully applied for the direct determination of monohydrogen phosphate in real life samples.
Talanta 10/2011; 86:121-7. · 3.79 Impact Factor
