scholarly journals Solvent Extraction of Thorium Using 5,11,17,23-Tetra[(2-ethyl acetoethoxyphenyl)(azo)phenyl]calix[4]arene

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Quang Hieu Tran ◽  
Van Tan Le ◽  
Van Cuong Nguyen
Keyword(s):  
Aqueous Solution ◽  
Solvent Extraction ◽  
Molar Absorptivity ◽  
Tolerance Limits ◽  
Acidic Aqueous Solution ◽  
Selective Method ◽  
Chloroform Layer ◽  
Effects Of Ph ◽  
Synthetic Solution

A rapid, sensitive, and selective method for determination of thorium based on the complex withortho-ester tetra-azophenylcalix[4]arene (TEAC) was described. In the presence of pH of 4–6, TEAC-Th(IV) complex is extracted from an acidic aqueous solution into chloroform layer. The absorbance intensity of complex was measured by UV-Vis spectrometer at 525 nm and the molar absorptivity was found to be 2.4 × 104. Beer’s law was obeyed in the range of 1.0 to 25 × 10−5 M thorium(IV). The effects of pH, TEAC concentration, and shaking time were also studied. The tolerance limits for several metal ions were calculated. The proposed method was applied to the determination of thorium in synthetic solution and in the monazite sand samples with good results.

scholarly journals Solvent Extraction And Spectrophotomteric Determination Of Cu(Ii) With Dicyclohexyl - 18- Crown-6

2013 ◽  
Vol 10 (3) ◽  
pp. 997-1004
Author(s):  
Baghdad Science Journal
Keyword(s):  
Aqueous Solution ◽  
Solvent Extraction ◽  
Correlation Coefficient ◽  
Extraction Efficiency ◽  
Molar Absorptivity ◽  
Liquid Extraction ◽  
Liquid Liquid Extraction ◽  
Coloured Complex

Liquid-Liquid Extraction of Cu(II) ion in aqueous solution by dicyclohexyl-18-crown-6 as extractant in dichloroethane was studied .The extraction efficiency was investigated by a spectrophometric method. The reagent form a coloured complex which has been a quantitatively extracted at pH 6.3. The method obeys Beer`s law over range from (2.5-22.5) ppm with the correlation coefficient of 0.9989. The molar absorptivity the stoichiometry of extracted complex is found to be 1:2. the proposed method is very sensitive and selective.

scholarly journals Spectrophotometric determination of phosphorus in coal and coal ash using bismuth-phosphomobybdate complex

2003 ◽  
Vol 68 (1) ◽  
pp. 65-73 ◽  
Author(s):  
Randjel Mihajlovic ◽  
Natasa Ignjatovic ◽  
Marija Todorovic ◽  
Ivanka Holclajtner-Antunovic ◽  
Vesna Kaljevic
Keyword(s):  
Aqueous Solution ◽  
Ascorbic Acid ◽  
Acid Medium ◽  
Spectrophotometric Method ◽  
Methyl Ketone ◽  
Coal Ash ◽  
Molar Absorptivity ◽  
Stable Complex ◽  
Tolerance Limits

A modified spectrophotometric method using the bismuth phosphomolybdate complex for the determination of phosphorus in coal and coal ash is suggested. Bismuth together with phosphate and molybdate forms a very stable complex in acid medium which turns blue ("molibdenum blue") by reduction with ascorbic acid. The apparent molar absorptivity of PBiMo is 1.66x104 dm3 mol-1cm-1 at 720 nm and 2.10x104 dm3 mol-1cm-1 at 670 nm isobutyl methyl ketone (MIBK). Interference caused by the ions present are within the tolerance limits (?2 %). Beer?s law is obeyed in the for concentration range to 0.6 ?g/mL (aqueous solution) and to 1.2 ?g/mL P (MIBK). The sensitivity of the proposed method is 0.0078 ?g/mL (aqueous solution) and 0.0066 ?g/mL (MIBK).

scholarly journals Simple spectrofluorometric determination of p-aminobenzoic and p-aminosalicylic acids in biological fluids by use of terbium-sensitized luminescence

1996 ◽  
Vol 42 (10) ◽  
pp. 1659-1665 ◽  
Author(s):  
E S Lianidou ◽  
P C Ioannou
Keyword(s):  
Aqueous Solution ◽  
Biological Fluids ◽  
Optimum Conditions ◽  
Serum Samples ◽  
Solution Ph ◽  
Acidic Aqueous Solution ◽  
Selective Method ◽  
Spectrofluorometric Determination ◽  
Aminosalicylic Acids

Abstract A novel, sensitive, and selective method has been developed for determination of p-aminobenzoic (PABA) and p-aminosalicylic (PAS) acids in the N-benzoyl-L-tyrosyl-PABA/ PAS test. PAS is measured as a ternary complex with terbium and EDTA (lambda(ex) = 324 nm, lambda(em) = 546 nm) in alkaline aqueous solution (pH approximately 12.6), whereas both compounds (PABA and PAS) are measured as ternary complexes with terbium and tri-n-octylphosphine oxide (lambda(ex) = 292 nm, lambda(em) = 546 nm) in weakly acidic aqueous solution (pH approximately 5.5). We inve stigated and implemented optimum conditions for formation of these complexes, yielding respective detection limits for PABA and PAS of 0.07 and 0.02 micromol/L and ranges of application of 0-10 and 0-40 micromol/L (final concentration). The method has been successfully applied to determinations of PABA and PAS in urine and, after alkaline hydrolysis, to determinations of PABA in serum that has been deproteinized with acetonitrile. Within-run imprecision of the PABA determination ranges from 0.8% to 4.2 % for urine samples and from 3.9% to 8.2% for serum samples; day-to-day imprecision varies from 3.2% to 10% for serum samples.

scholarly journals Nitroso-R-salt as a sensitive spectrophotometric reagent for the determination of paracetamol in pharmaceutical preparations

2009 ◽  
Vol 6 (3) ◽  
pp. 570-577
Author(s):  
Baghdad Science Journal
Keyword(s):  
Aqueous Solution ◽  
Statistical Difference ◽  
Pharmaceutical Preparations ◽  
Molar Absorptivity ◽  
Calibration Graph ◽  
Subsequent Reaction ◽  
Experimental Conditions ◽  
Colored Complex ◽  
British Pharmacopoeia

Nitroso-R-salt is proposed as a sensitive spectrophotometric reagent for the determination of paracetamol in aqueous solution. The method is based on the reaction of paracetamol with iron(III) and subsequent reaction with nitroso-R-salt to yield a green colored complex with maximum absorption at 720 nm. Optimization of the experimental conditions was described. The calibration graph was linear in the concentration range of 0.1 – 2.0 ?g mL-1 paracetamol with a molar absorptivity of 6.9 × 104 L mol-1 cm-1. The method was successfully applied to the determination of paracetamol in pharmaceutical preparations without any interference from common excipients. The method has been statistically evaluated with British Pharmacopoeia method and no statistical difference between methods was found at the 95% confidence level.

scholarly journals Spectrophotometric method for the determination of Captopril in pharmaceutical formulations

2013 ◽  
Vol 10 (3) ◽  
pp. 965-970
Author(s):  
Baghdad Science Journal
Keyword(s):  
Aqueous Solution ◽  
Spectrophotometric Method ◽  
Pharmaceutical Formulations ◽  
Molar Absorptivity ◽  
Maximum Absorption ◽  
Neutral Medium ◽  
Pharmaceutical Tablets ◽  
Colored Product ◽  
Sensitive Spectrophotometric Method

A simple, rapid and sensitive spectrophotometric method has been developed for the determination of captopril in aqueous solution. The method is based on reaction of captopril with 2,3-dichloro 1,4- naphthoquinon(Dichlone) in neutral medium to form a stable yellow colored product which shows maximum absorption at 347 nm with molar absorptivity of 5.6 ×103 L.mole-1. cm-1. The proposed method is applied successfully for determination of captopril in commercial pharmaceutical tablets.

A highly selective and sensitive fluorescent chemosensor for Hg2+ based on a pyridine-appended π-conjugated ligand

RSC Advances ◽  
2014 ◽  
Vol 4 (87) ◽  
pp. 47000-47004 ◽  
Author(s):  
Yaping Yang ◽  
Xin-Long Ni ◽  
Tao Sun ◽  
Hang Cong ◽  
Gang Wei
Keyword(s):  
Aqueous Solution ◽  
Organic Synthesis ◽  
Fluorescence Enhancement ◽  
Fluorescent Chemosensor ◽  
Selective Method ◽  
Pure Aqueous Solution

A sensitive and selective method for the determination of Hg2+ cations by fluorescence enhancement in pure aqueous solution was developed and obtained by simple organic synthesis.

scholarly journals Changes in the Surface Area of Silica-supported 12-Molybdophosphoric Acid in Relation to the Degree of Loading and the Calcination Temperature

1994 ◽  
Vol 11 (2) ◽  
pp. 83-93 ◽  
Author(s):  
L.B. Khalil ◽  
W.E. Mourad ◽  
B.S. Girgis
Keyword(s):  
Aqueous Solution ◽  
Surface Area ◽  
Silica Gel ◽  
Heteropoly Acid ◽  
Surface Acidity ◽  
Molybdophosphoric Acid ◽  
Surface Species ◽  
Considerable Decrease ◽  
Acidic Aqueous Solution

A technical silica gel (Grace-113) was impregnated with 12-molybdophosphoric solution to attain loadings of 0.72–13.4 wt.%. The air-dried solids were then calcined for 3 h at 400, 600 and 800°C, respectively, followed by determination of their N2 adsorption isotherms. The silica gel was thermally stable and suffered about 15% loss in area at 800°C. The impregnated silicas showed considerable decrease in surface area as a function of their heteropoly acid content. Two processes are suggested as taking part in the modification of pore structure: (1) diffusion of the aqueous heteropoly acid solution and its subsequent deposition; and (2) dissolution of silica gel in the acidic aqueous solution followed by interaction with HPMo to form either molybdosilicate or P–Si exchange products. Correlation with the previously studied catalytic conversion of isopropanol indicated that the activity was independent of the surface area. Catalytic dehydration on the 600°C and 800°C products seems to be associated with silicate, molybdate or MoO3 surface species rather than being due to surface acidity or the extent of the surface area.

Rapid Separation of Technetium from Fission Products

1966 ◽  
Vol 5 (1) ◽  
Author(s):  
Gerald Goldstein ◽  
John A. Dean
Keyword(s):  
Solvent Extraction ◽  
Fission Products ◽  
Rapid Separation ◽  
Selective Method ◽  
Short Irradiation

SummaryThe solvent extraction of technetium, as pertechnetate ion, with cyclohexanone was studied and proved to be an unusually rapid, efficient, and selective method of separation. This separation was applied in the determination of the number of fissions occurring in a short irradiation of uranium by measurement of

Gas Chromatographic Determination of Diethylstilbestrol Dimethyl Ether in Diethylstilbestrol

1972 ◽  
Vol 55 (1) ◽  
pp. 185-186
Author(s):  
F E Gainer ◽  
W J Chiasson
Keyword(s):  
Aqueous Solution ◽  
Dimethyl Ether ◽  
Chloroform Solution ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Detector Response ◽  
Chloroform Layer ◽  
Internal Standard Peak ◽  
Linear Plot

Abstract A GLC method is described for the determination of the dimethyl ether of diethylstilbestrol (DME) in diethylstilbestrol (DES). A 1 g sample of DES is dissolved in an aqueous solution of 0.5N NaOH and then extracted with a chloroform solution containing benefin, the internal standard. An aliquot of the chloroform layer is chromatographed and the DME peak is measured relative to the internal standard peak. The method was tested for accuracy within the 11–110 ppm range and a linear plot of detector response vs. concentration was obtained.

Spectrophotometric Determination of Cyclamate in Foods: NMKL Collaborative Study

1987 ◽  
Vol 70 (3) ◽  
pp. 588-590
Author(s):  
Anna-Maija K Sjoberg ◽  
Timo A Alanko
Keyword(s):  
Aqueous Solution ◽  
Ethyl Acetate ◽  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Collaborative Study ◽  
Soft Drinks ◽  
Uv Absorption ◽  
Acidic Aqueous Solution ◽  
Coefficients Of Variation

Abstract A spectrophotometric method for the determination of cyclamate was collaboratively studied in 9 laboratories. Ethyl acetate is added to extract cyclamate from acidic aqueous solution into water, and the cyclamate is then quantitatively converted to /V,./V-dichlorocyclohexylamine by adding excess hypochlorite. A',A'-Dichlorocyclohexylamine is determined by measuring its UV absorption at 314 nm. Six samples, 3 soft drinks with cyclamate levels of 0.36-0.47 g/kg and 3 jams with levels of 1.23-1.50 g/kg, were included in the study. Average recoveries of cyclamate were 99.7% in the soft drinks and 103.8% in the jams. Reproducibility coefficients of variation were 6.7% for the soft drinks and 4.4% for the jams.

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