Potentiometric Titration of Triazolethiols and Tetrazolethiols with Iodine in Alkaline Medium

2002 ◽  
Vol 67 (8) ◽  
pp. 1193-1199 ◽  
Author(s):  
Witold Ciesielski ◽  
Anna Krenc
Keyword(s):  
Potentiometric Titration ◽  
Alkaline Medium ◽  
Potential Drop ◽  
Potentiometric Titration Curve ◽  
Indicator Electrode ◽  
Nernst Equation ◽  
Relative Standard ◽  
End Point Detection ◽  
Point Detection

The iodimetric determination of triazolethiols and tetrazolethiols in alkaline medium is presented. The volumetric titration with potentiometric end-point detection was applied. The range of determination, in which the error is lower than 1%, is 20-2 000 μmol for 1H-1,2,4-triazole-3-thiol (1), 25-1 000 μmol for 3-phenyl-1H-1,2,4-triazole-5-thiol (2), 25-500 μmol for 4-methyl-5-(trifluoromethyl)-4H-1,2,4-triazole-3-thiol (3), 50-500 μmol for 3-amino-1H-1,2,4-triazole-5-thiol (4), 10-1 000 μmol for sodium (5-mercapto-1H-tetrazol-1-yl)acetate (5), 125-500 μmol for 1-phenyl-1H-tetrazole-5-thiol (6) and 50-1 000 μmol for 1-(4-hydroxyphenyl)-1H-tetrazole-5-thiol (7). The relative standard deviation for all determinations was below 1%. The shape of potentiometric titration curve of 6 and 7 is noteworthy at higher concentrations of sodium hydroxide and depends on the type of the indicator electrode (platinum, gold). An introduction of iodine results in a strong potential drop. Some systems do not follow the Nernst equation.

scholarly journals Coulometric titrations of bases in propylene carbonate and γ-butyrolactone using hydroquinone as the depolarizer and a quinhydrone indicator electrode

2000 ◽  
Vol 65 (8) ◽  
pp. 587-593 ◽  
Author(s):  
Lj.N. Jaksic ◽  
R.M. Dzudovic ◽  
R.P. Mihajlovic ◽  
Z.D. Stanic
Keyword(s):  
Propylene Carbonate ◽  
Platinum Electrode ◽  
Indicator Electrode ◽  
Hydrogen Ions ◽  
Organic Bases ◽  
Oxidation Potentials ◽  
End Point Detection ◽  
Point Detection ◽  
Current Potential

The application of hydroquinone for the coulometric generation of hydrogen ions in propylene carbonate (PC) and ?-butyrolactone (GBL) is described. The current-potential curves recorded for this depolarizer, titrated bases, indicator and the solvents used showed that the investigated depolarizer is oxidized at lower potentials than the oxidation potentials of other components in the solution. The hydrogen ions generated by the oxidation of hydroquinone were used for the titration of organic bases (triethylamine, n-butylamine, pyridine, quinoline, aniline, N,N'-diphenylguanidine, piperidine, and 2,2?-bi?pyridine) in PC and GBL with with visual (Crystal Violet as indicator) and potentiometric end-point detection using a quinhydrone electrode as the indicator electrode. The quinhydrone added to the to be analyzed solution served both as a source of hydrogen ions and, together with the immersed platinum electrode, as a quinhydrone electrode. The relative error of the determination of the bases was about 1%.

scholarly journals A quick method to determine the content of sulfates in silicic and aluminosilicate fillers

2007 ◽  
Vol 9 (1) ◽  
pp. 33-35
Author(s):  
Barbara Sołtysik
Keyword(s):  
Potentiometric Titration ◽  
Statistical Interpretation ◽  
Selective Electrode ◽  
Quick Method ◽  
Analytical Technique ◽  
End Point ◽  
End Point Detection ◽  
Parameter Ranges ◽  
Point Detection

A quick method to determine the content of sulfates in silicic and aluminosilicate fillers The paper presents the possibility of using barium-selective electrode to a potentiometric determination of sulfates in silicic and aluminosilicate fillers. The results of sulfates potentiometric titration in silicic and aluminosilicate fillers are described. A statistical interpretation of the results was carried out. The recommended method is based on the end-point detection of sulfates potentiometric titration in hydro-alcoholic medium by means of barium chlorate(VII) titrant. The potentiometric titration, which uses an ion-selective electrode as the indicator for the end-point was applied as the analytical technique. The parameter ranges for accurate sulfates determination in model solutions and the method of samples' preparation for analysis were investigated.

The determination of phosphorus in organic compounds with potentiometric end-point detection

1970 ◽  
Vol 58 (1) ◽  
pp. 52-57 ◽  
Author(s):  
J. Slanina ◽  
P. C. M. Frintrop ◽  
J. F. Mansveld ◽  
B. Griepink
Keyword(s):  
Organic Compounds ◽  
End Point ◽  
End Point Detection ◽  
Point Detection

Fluorometric and Spectrophotometric Determination of Pirbuterol Hydrochloride in Authentic and Dosage Forms

1985 ◽  
Vol 68 (6) ◽  
pp. 1222-1225
Author(s):  
Mohamed E Mohamed ◽  
Hassan Y Aboul-Enein
Keyword(s):  
Potentiometric Titration ◽  
Alkaline Medium ◽  
Spectrophotometric Determination ◽  
Fluorescence Intensity ◽  
Perchloric Acid ◽  
Authentic Sample ◽  
Dosage Forms ◽  
Fluorometric Method ◽  
The Mean

Abstract Pirbuterol hydrochloride has been assayed in alkaline medium by using a fluorometric method to measure fluorescence intensity at 372 nm with excitation at 310 nm and by the ▵A method at 242 nm.The linearity ranges are 0.5-4 μg/mL and 10-50 μg/mL, respectively. An authentic pirbuterol HC1 sample was analyzed by nonaqueous potentiometric titration using 0.1N perchloric acid, and the results were compared with those for fluorometric and AA methods. The mean percent recoveries for the authentic sample were 98.72 ± 1.13 and 99.24 ± 0.85, respectively. When applied to commercial capsules containing 10 mg and 15 mg each, the fluorometric method gave mean percent recoveries of 101.11 ± 1.05 and 98.12 ± 0.93; the ▵A method gave mean percent recoveries of 100.57 ± 0.83 and 97.80 ± 0.75, respectively.

scholarly journals Spectrophotometric Method for Determination of Paraquat in Food and Biological Samples

1997 ◽  
Vol 80 (2) ◽  
pp. 388-391 ◽  
Author(s):  
Ritu Kesari ◽  
Manish Rai ◽  
Vinay Kumar Gupta
Keyword(s):  
Standard Deviation ◽  
Metal Ions ◽  
Relative Standard Deviation ◽  
Alkaline Medium ◽  
Spectrophotometric Method ◽  
Biological Samples ◽  
Molar Absorptivity ◽  
Relative Standard ◽  
Sensitive Spectrophotometric Method

Abstract A sensitive spectrophotometric method was developed for determination of paraquat, a widely used herbicide. Paraquat was reduced with glucose in an alkaline medium, and the blue radical ion obtained was measured at 600 nm. Beer’s law was obeyed at 0.1–1.2 ppm paraquat. The molar absorptivity was 1.26 × 105 L mol-1 cm-1. The standard deviation and relative standard deviation were ± 0.007 and 2.0%, respectively, for 5 μg paraquat/10 mL analyzed over 7 days. The method was free from interference by other commonly used pesticides and metal ions. The method may be used to the determine paraquat in plants, fruits, grains, water, blood, and urine.

Determination of titratable acidity of wines and total acidity of vinegars by discontinuous flow analysis using photometric end-point detection

The Analyst ◽  
1991 ◽  
Vol 116 (10) ◽  
pp. 1051 ◽  
Author(s):  
Terence J. Cardwell ◽  
Robert W. Cattrall ◽  
Graeme J. Cross ◽  
Gregory R. O'Connell ◽  
John D. Petty ◽  
...  
Keyword(s):  
Flow Analysis ◽  
Titratable Acidity ◽  
Total Acidity ◽  
Discontinuous Flow ◽  
End Point ◽  
End Point Detection ◽  
Point Detection

scholarly journals Microtitrimetric determination of a drug content of pharmaceuticals containing olanzapine in non-aqueous medium

2009 ◽  
Vol 15 (2) ◽  
pp. 77-81 ◽  
Author(s):  
Kanakapura Basavaiah ◽  
Nagaraju Rajendraprasad ◽  
Basavaiah Vinay
Keyword(s):  
Standard Deviation ◽  
Aqueous Medium ◽  
Reference Method ◽  
Standard Addition ◽  
Cost Effective ◽  
Pharmaceutical Products ◽  
Relative Standard ◽  
Bulk Drug ◽  
Point Detection

Two simple, rapid, reliable and cost-effective methods based on titrimetry in non-aqueous medium are described for the determination of olanzapine in pharmaceuticals. In these methods, the drug dissolved in the glacial acetic acid was titrated with the acetous perchloric acid with visual and potentiometric end point detection, crystal violet being used as the indicator for visual titration. The methods are applicable over 1-15 mg range of olanzapine. The procedures were applied to determine olanzapine in pharmaceutical products and the results were found to be in a good agreement with those obtained by the reference method. Associated pharmaceutical materials did not interfere. The precision results, expressed by inter-day and intra-day relative standard deviation values, were satisfactory, higher than 2%. The accuracy was satisfactory as well. The methods proved to be suitable for the analysis of olanzapine in bulk drug and in tablets. The accuracy and reliability of the methods were further ascertained by recovery studies via a standard addition technique with percent recoveries in the range 97.51-103.7% with a standard deviation of less than 2%.

Sign in / Sign up

Export Citation Format

Share Document