Determination of the concentration of silicon dioxide in crystal by potentiometric titration with a fluoride-selective electrode

1994 ◽  
Vol 51 (3-4) ◽  
pp. 149-153
Author(s):  
S. M. Chesnokova ◽  
E. P. Lashuk
2007 ◽  
Vol 52 (2) ◽  
pp. 169-184 ◽  
Author(s):  
Milos Rajkovic ◽  
Ivana Novakovic ◽  
Aleksandar Petrovic

The amount of titration acid in must is in the largest number of cases with in the range 5.0-8.0 g/dm3. Wines, as a rule, contain less acids than must, and according to Regulations, titratable acidity is in the range of 4.0-8.0 g/dm3 expressed in tartaric acid, because a part of tartaric acid is deposited in the form of salts (tartar or argol) during alcohol fermentation. For wines that contain less than 4 g/dm3 of titratable acids there arises a suspicion about their origin, that is, that during the preparation some illegal acts were done. Because of that, the aim of this paper is to determine titratable acidity in white wine, using standard methods of determination, which are compared with the results received by potentiometric titration using ion-selective electrode. According to the received results it can be seen that wine titration with indicator gives sufficient reliable values of wine titration acidity. However, as potentiometric titration at pH value 7.00 is more reliable and objective method, the values of titratable acids content in wine, expressed through tartaric acid, are given according to this result. The analysis of differential potentiometric curves shows that these curves can give us an answer to the question of the presence of a larger amount of other nonorganic substances, which have already existed in wine. However, none of the used methods gives absolutely reliable answer what substances are present in analysed samples.


2004 ◽  
Vol 59 (3) ◽  
pp. 291-295 ◽  
Author(s):  
L. F. Naumenko ◽  
N. M. Buneeva ◽  
R. N. Korneeva ◽  
V. F. Selemenev ◽  
D. V. Nemtsev

2008 ◽  
Vol 6 (4) ◽  
pp. 607-612 ◽  
Author(s):  
Cecylia Wardak

AbstractA new all plastic sensor for Co2+ ions based on 2-amino-5 (hydroxynaphtyloazo-1′)-1,3,4 thiadiazole (ATIDAN) as ionophore was prepared. The electrode exhibits a low detection limit of 1.5 × 10−6 mol L−1 and almost theoretical Nernstian slope in the activity range 4.0 × 10−6–1 × 10−1 mol L−1 of cobalt ions. The response time of the sensor is less than 10 s and it can be used over a period of 6 months without any measurable divergence in potential. The proposed sensor shows a fairly good selectivity for Co(II) over other metal ions. The electrode was successfully applied for determination of Co2+ in real samples and as an indicator electrode in potentiometric titration of Co2+ ions with EDTA.


1983 ◽  
Vol 48 (4) ◽  
pp. 1137-1143 ◽  
Author(s):  
Jaromír Kalous ◽  
Karel Vytřas ◽  
Alena Terberová

Some possibilities have been studied of application of the Crytur 20-15 Ca2+-selective electrode in volumetric analysis especially for determination of the compounds which react with calcium(II) salts to form precipitates or complexes. Titrations with standard calcium(II) nitrate solution have particularly proved useful for determination of aminocarboxylic acids, but sufficiently developed potentiometric titration curves have also been obtained in titrations of fluoride, oxalate and higher carboxylic acid anions (soaps). Also reliable results have been obtained in titrations of Ca2+ besides Mg2+ with standard EGTA solution.


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