Iodide Ion Sensor for Indirect Determination of As (III) in Water

2010 ◽  
Vol 117 ◽  
pp. 93-98
Author(s):  
A. Nyachhyon ◽  
A.P. Yadav ◽  
Krishna Manandhar ◽  
Raja Ram Pradhananga
Keyword(s):  
Polycrystalline Material ◽  
Low Cost ◽  
Direct Determination ◽  
Selectivity Coefficient ◽  
Indirect Determination ◽  
Iodide Ion ◽  
Silver Sulphide ◽  
Nernstian Slope ◽  
Co Precipitation

A simple, low cost and portable iodide sensor for the indirect determination of As(III) has been developed from the polycrystalline material obtained by co-precipitation of silver sulphide and silver iodide from aqueous solution. The Ag2S-AgI sensor was found to behave well up to the iodide concentration of 1×10-6 M with a Nernstian slope 57.5 mV per decade change in concentration. The selectivity coefficient of sensor containing iodide ion in the presence of Br- and Cl- ions was found to be 1.77 × 10-2 and 7.94 × 10-3, respectively indicating that these ions do not interfere in the response of iodide sensor to iodide ion. The electrode was successfully used for the direct determination of iodide and indirect determination of As(III) by titrating with cerric ammonium sulphate at pH 2. The results obtained from this method are comparable to the existing methods for the estimation of As(III).

scholarly journals Low Cost Electrochemical Sensors for Silver, Chloride, Bromide and Iodide Ions

1970 ◽  
Vol 6 (6) ◽  
pp. 33-36 ◽  
Author(s):  
Raja Ram Pradhananga ◽  
Armila Rajbhandari Nyachhyon
Keyword(s):  
Electrochemical Sensors ◽  
Silver Chloride ◽  
Low Cost ◽  
Selectivity Coefficient ◽  
Chloride Ions ◽  
Equimolar Mixture ◽  
Potentiometric Selectivity ◽  
Iodide Ion ◽  
Silver Sulphide ◽  
Potentiometric Selectivity Coefficient

Low cost all solid state pressed pellet Ag+, halides and sulphide sensitive electrodes based on silver sulphide were fabricated. The electrodes have been tested and results compare favorably with commercial electrodes. Pure Ag2S electrode with internal silver metal contact was found to follow Nernstian equation from 1 x 10-1 to 1 x 10-5 M of silver ion with slope equal to 59.8 mV per decade change in concentration of Ag+ - ion. Electrodes fabricated from equimolar mixture of Ag2S and Ag - halide was found to be sensitive to the respective halide and silver ions. Iodide ion selective electrode prepared from a equimolar mixture of Ag2S and AgI was found to be selective to iodide ion with negligible interference from bromide and chloride ions. The potentiometric selectivity coefficient Kpot I,Br, Kpot I,Cl were found to be 1.77x10-2 and 7.94x10-3 respectively. All these electrodes were found to be selective to Ag+ ion with negligible interference with Kpot Ag, Hg equal to 1 x 10-5 Hg++ ion with selectivity coefficient. Keywords: Ion selective electrodes; Potentiometric selectivity coefficient; Silver sulphide.   DOI: 10.3126/sw.v6i6.2631 Scientific World, Vol. 6, No. 6, July 2008 33-36

scholarly journals Preparation of halide sensors by means of co-precipitation of silver sulphide and silver halide

2013 ◽  
Vol 30 ◽  
pp. 168-173 ◽  
Author(s):  
Armila Rajbhandari ◽  
Krishna Manandhar ◽  
Raja Ram Pradhananga
Keyword(s):  
Response Time ◽  
Linear Response ◽  
Silver Halide ◽  
Chemical Society ◽  
Selectivity Coefficient ◽  
Chloride Ions ◽  
Iodide Ions ◽  
Silver Sulphide ◽  
Co Precipitation

Halide sensors have been prepared in the laboratory by means of co-precipitation of silver sulphide and silver halide and is used for the determination of iodide, bromide and chlorides ions. The iodide sensors show a Nernstian response in the concentration range of 10-1 to 10-6M iodide ions, bromide sensors show a linear response in the concentration range of 10-1 to 10-5M bromide ions while chloride sensors show linear response upto the concentration range of 10-4M chloride ions. The response time of all the electrodes, is < 1minute. The iodide sensors were found to be selective towards iodide ions in the presence of Cl- and Br- ions while bromide and chloride sensors interferred by iodide ions as indicated by selectivity coefficient values of 3.98 and 48.9 respectively. These sensors have been successfully applied for potentiometric titrations.DOI: http://dx.doi.org/10.3126/jncs.v30i0.9390Journal of Nepal Chemical Society Vol. 30, 2012 Page:  168-173 Uploaded date: 12/20/2013   

scholarly journals Efficiency of portable chlorophyll meters in assessing the nutritional status of wheat plants

2015 ◽  
Vol 19 (12) ◽  
pp. 1148-1151 ◽  
Author(s):  
Alessana F. Schlichting ◽  
Edna M. Bonfim-Silva ◽  
Matheus de C. Silva ◽  
William Pietro-Souza ◽  
Tonny J. A. da Silva ◽  
...  
Keyword(s):  
Nutritional Status ◽  
Chlorophyll Content ◽  
Direct Determination ◽  
Probability Level ◽  
Indirect Determination ◽  
N Concentration ◽  
Randomized Design ◽  
Chlorophyll Index ◽  
Completely Randomized Design

ABSTRACT The objective of this study was to verify the efficiency of two portable chlorophyll meters (Minolta SPAD® 502 and Falker ClorofiLOG® 1030) in assessing the nutritional status of wheat plants, correlating the indices from the devices and the direct determination of chlorophyll content with the concentration of nitrogen (N) in the plant. The experiment was conducted in a greenhouse, in pots with 5 dm3 of Oxisol, in a completely randomized design, with six N doses (0, 80, 160, 240, 320 and 400 mg dm-3) and five replicates. At 47 days after emergence, the readings of SPAD and Falker indices and the quantification of chlorophyll content and N concentration in wheat plants were performed, as well as analysis of variance and correlation test, both at 0.05 probability level. The chlorophyll meters Minolta SPAD® 502 and Falker ClorofiLOG® 1030 do not differ with respect to the indirect determination of chlorophyll in wheat plants. The Falker chlorophyll index was statistically equal to the chlorophyll content. Indirect chlorophyll indices and chlorophyll content showed a high correlation with the N concentration in the plant.

scholarly journals Utility of Nickel for Atomic Absorption Spectrophotometric Determination of Selected Acidic Drugs

2001 ◽  
Vol 69 (2) ◽  
pp. 189-201 ◽  
Author(s):  
Hesham Salem ◽  
Khadiga Kelani ◽  
Abdalla Shalaby
Keyword(s):  
Atomic Absorption ◽  
Diclofenac Sodium ◽  
Direct Determination ◽  
Pharmaceutical Preparations ◽  
Accurate Method ◽  
Flufenamic Acid ◽  
Indirect Determination ◽  
Acidic Drugs ◽  
Precision And Accuracy

A simple and accurate method is described for the quantitative determination of flufenamic acid, mefenamic acid, tranexamic acid, furosemide, diclofenac sodium and thiaprofenic acid by precipitation reactions with nickel(II) followed by direct determination of the ions in the precipitate or indirect determination of the ions in the filtrate by atomic absorption spectroscopy. Statistical analysis of the results compared to assays used in pharmacopeas and the Amax. methods revealed equal precision and accuracy. Furthermore the assays were also applied for the determination of these drugs in pharmaceutical preparations.

scholarly journals Spectrophotometric determination of iron (III) catalyst in organic compound chlorinations

2021 ◽  
Vol 3 (8) ◽  
pp. 13-21
Author(s):  
Fotis Rigas ◽  
Danae Doulia
Keyword(s):  
Organic Compound ◽  
Methyl Ethyl Ketone ◽  
Spectrophotometric Determination ◽  
Low Cost ◽  
Direct Determination ◽  
Molar Absorptivity ◽  
Methyl Ethyl ◽  
Easy Method ◽  
Color Development

In the science or industrial practice of chemical processes, iron (III) is sometimes used as a catalyst in organic compound chlorinations due to its effectiveness and low cost. Thus, a fast and easy method of determination in the system is useful especially when metallic iron is used as a precursor which is readily converted into iron (III) chloride by the gaseous chlorine used in the chlorination reactor. In the latter case, the determination of the produced catalytically effective iron (III) is a prerequisite for controlling the kinetic progress of chlorination. In this work, a method for the spectrophotometric determination of iron (III) chloride in organic media after complexation with methyl ethyl ketone is investigated. The formation of a strong o-complex of iron (III) with methyl ethyl ketone allows direct determination of iron at 360 nm.Beer’s law is valid up to absorbance 2.42, where the iron (III) concentration is 20.7 mg·L-1, with molar absorptivity (e) equal to 6.532×103 L·mol-1·cm-1 and Sandell’s sensitivity 8.5×10-3 ug·cm- 2. Standing time for color development is of the order of a few seconds and stability of color measurements exceeds 12 months. The method may be used among other applications in organic compounds chlorinations catalyzed by iron. These systems are complicated due to the coexistence of various complexes. Nevertheless, the method proposed being simple, fast, and not depending on the composition of the chlorination mixture and the amount of methyl ethyl ketone added was found to be suitable.

scholarly journals Atomic Absorption Spectrometry of Acidic Pharmaceutical Constituents by Precipitation Using Co (II), Cd (II) and Mn (II)

2000 ◽  
Vol 68 (4) ◽  
pp. 343-355 ◽  
Author(s):  
Hesham Salem ◽  
Magda El-Maamli ◽  
Abdalla Shalaby
Keyword(s):  
Tranexamic Acid ◽  
Atomic Absorption ◽  
Mefenamic Acid ◽  
Direct Determination ◽  
Absorption Spectrometry ◽  
Flufenamic Acid ◽  
Molar Ratio ◽  
Cadmium Nitrate ◽  
Indirect Determination

Simple and accurate methods are described for the quantitative determination of flufenamic acid, mefenamic acid and tranexamic acid utilizing precipitation reactions with cobalt, cadmium and manganese. The acidic drugs were precipitated from their neutral alcoholic solutions with cobalt sulphate, cadmium nitrate or manganese chloride standard solutions followed by direct determination of the ions in the precipitate or indirect determination of the ions in the filtrate by atomic absorption spectroscopy. The optimum conditions for precipitation were carefully studied. The molar ratio of the reactants was ascertained. Statistical analysis of the results compared to the results of the official methods revealed equal precision and accuracy. The suggested procedures were applied for determining flufenamic acid, mefenamic acid and tranexamic acid in pharmaceutical preperations as well and proved validity.

Voltammetric method for determination of glutathione on a gold-carbon-containing electrode

2019 ◽  
Vol 85 (1(I)) ◽  
pp. 28-34
Author(s):  
A. S. Gashevskaya ◽  
E. V. Dorozhko ◽  
E. I. Korotkova ◽  
E. A. Pashkovskaya ◽  
O. A. Voronova ◽  
...  
Keyword(s):  
High Performance ◽  
Biological Fluids ◽  
Low Cost ◽  
Pharmaceutical Preparations ◽  
Electrochemical Methods ◽  
Voltammetric Method ◽  
Indirect Determination ◽  
Biochemical Processes ◽  
Glutathione Determination

Glutathione (GSH) is one of the most important thiol-containing antioxidants involved into various biochemical processes in the human body. Glutathione determination in biological fluids (saliva, urine, serum) and pharmaceutical preparations is rather important for clinical practice. Various analytical methods — spectrophotometry, fluorimetry, high-performance liquid chromatography, NMR spectroscopy, capillary electrophoresis and electrochemical methods — are widely used for this purpose. Electrochemical methods are characterized by easy implementation, low cost and possibility of miniaturization. The electrochemical behavior of reduced (GSH) and oxidized (GSSG) glutathione on a gold-carbon-containing electrode (AuCE) was studied using cathodic voltammetry with different methods of removing oxygen from an electrochemical cell: nitrogen sparging and addition of sodium sulfite (4 mol/dm3). It has been shown that traces of H2O2 that remain in the near-electrode layer on the AuCE even after oxygen removal influence the electrochemical properties of GSH at a cathode sweep of the potential from 0 to –1.8 V: GSH is oxidized by H2O2 to GSSG, the most important product of this reaction is O2. An indirect determination of GSH by the current of oxygen reduction in the Na2SO3 medium in the concentration range from 0.5 × 10–8 to 4.2 × 10–8 mol/dm3 with a detection limit of 2.5 × 10–9 mol/dm3 is proposed. The developed voltammetric method is approved for the determination of GSH in certain pharmaceutical preparations.

scholarly journals Electrochemical Characterization of Laboratory Fabricated Bromide Ion Selective Electrode

2016 ◽  
Vol 21 (1) ◽  
pp. 76-81 ◽  
Author(s):  
Armila Rajbhandari Nyachhyon ◽  
Krishna Manandhar ◽  
Raja Ram Pradhananga
Keyword(s):  
Electrochemical Impedance ◽  
Selectivity Coefficient ◽  
Electrode System ◽  
Ion Selective Electrode ◽  
Ion Concentration ◽  
Selective Electrode ◽  
Potentiometric Response ◽  
Bromide Ion ◽  
Silver Sulphide ◽  
Co Precipitation

Bromide ion selective electrode (Br-ISE) have been successfully fabricated in the laboratory. The polycrystalline Ag2S-AgBr membrane material of Br-ISE was prepared by co-precipitation of silver sulphide and silver bromide from aqueous solution and was characterized by X-ray diffractometry (XRD). XRD results showed that material is in mixed phase state having Ag3SBr, Ag2S and AgBr. Scanning electron microscopy (SEM) has been used to study the texture of the surface. The potentiometric response has been investigated by 2 electrode system whereas 3 electrode systems have been used for electrochemical impedance spectroscopy (EIS). The electrode was found to behave well up to the bromide concentration of 1x10-5M with a Nernstian slope of 58 mV per decade change in bromide ion concentration. The selectivity coefficient of electrode containing bromide ion in the presence of I- and Cl- ions was found to be 3.98 and 8x10-2, respectively indicating that I- and Cl- ions interfere in the response of bromide electrode to bromide ion. The EIS studies shows that the charge transfer process is the key mechanism that is going on at the electrode/ electrolyte interface and electrode/ back contact interface.Journal of Institute of Science and TechnologyVol. 21, No. 1, 2016, page: 76-81

Development of a low cost microfluidic sensor for the direct determination of nitrate using chromotropic acid in natural waters

2015 ◽  
Vol 7 (13) ◽  
pp. 5396-5405 ◽  
Author(s):  
Deirdre Cogan ◽  
Cormac Fay ◽  
David Boyle ◽  
Conor Osborne ◽  
Nigel Kent ◽  
...  
Keyword(s):  
Natural Waters ◽  
Simple Procedure ◽  
Low Cost ◽  
Direct Determination ◽  
Chromotropic Acid ◽  
First Time

This study has demonstrated, for the first time, a microfluidic autonomous analyser for the direct determination of nitrate, incorporating a modified version of the chromotropic method resulting in a direct, quick, inexpensive and simple procedure to measure nitrate in situ.

scholarly journals Novel Potentiometric 2,6-Dichlorophenolindo-phenolate (DCPIP) Membrane-Based Sensors: Assessment of Their Input in the Determination of Total Phenolics and Ascorbic Acid in Beverages

Sensors ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 2058 ◽  
Author(s):  
Nada H. A. Elbehery ◽  
Abd El-Galil E. Amr ◽  
Ayman H. Kamel ◽  
Elsayed A. Elsayed ◽  
Saad S. M. Hassan
Keyword(s):  
Direct Determination ◽  
Inorganic Ions ◽  
Ion Association ◽  
Fast Response ◽  
Plasticized Pvc ◽  
Promising Tool ◽  
Total Antioxidant ◽  
Nernstian Slope ◽  
High Potential Stability

In this work, we demonstrated proof-of-concept for the use of ion-selective electrodes (ISEs) as a promising tool for the assessment of total antioxidant capacity (TAC). Novel membrane sensors for 2,6-dichlorophenolindophenolate (DCPIP) ions were prepared and characterized. The sensors membranes were based on the use of either CuII-neocuproin/2,6-dichlorophenolindo-phenolate ([Cu(Neocup)2][DCPIP]2) (sensor I), or methylene blue/2,6-dichlorophenolindophenolate (MB/DCPIP) (sensor II) ion association complexes in a plasticized PVC matrix. The sensors revealed significantly enhanced response towards DCPIP ions over the concentration range 5.13 × 10−5–1.0 × 10−2 and 5.15 × 10−5–1.0 × 10−2 M at pH 7 with detection limits of 6.3 and 9.2 µg/mL with near-Nernstian slope of −56.2 ± 1.7 and −51.6 ± 2 mV/decade for sensors I and II, respectively. The effects of plasticizers and various foreign common ions were also tested. The sensors showed enhanced selectivity towards DCPIP over many other phenolic and inorganic ions. Long life span, high potential stability, high reproducibility, and fast response were also observed. Method validation was also verified by measuring the detection limit, linearity range, accuracy, precision, repeatability and between-day-variability. The sensors were introduced for direct determination of TAC in fresh and canned juice samples collected from local markets. The obtained results agreed fairly well with the data obtained by the standard method.

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