Comparison of different methods for determination of sodium chloride in cheese
The content of NaCl (weight fraction of Cl-ions, in %) was analysed in different cheeses, which were bought in supermarkets, and made by domestic manufacturers. Sodium chloride in cheese samples was analysed after the extraction of chloride by nitric acid solution. Concentration of chloride ions was...
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Veröffentlicht in: | Journal of agricultural sciences (Belgrade, Serbia) Serbia), 2010, Vol.55 (1), p.65-77 |
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Zusammenfassung: | The content of NaCl (weight fraction of Cl-ions, in %) was analysed in
different cheeses, which were bought in supermarkets, and made by domestic
manufacturers. Sodium chloride in cheese samples was analysed after the
extraction of chloride by nitric acid solution. Concentration of chloride
ions was potentiometricly determined, with the chloride selective electrode
and titrimetricly by Volhard method. According to the results in the analysis
of the content of NaCl in %, by different methods it was determined that the
share of NaCl in % ranged from 0.66 to 4.43% (determined by potentiometric
route) that is from 0.97 to 4.72% (determined by titrimetric route by Volhard
method). The difference in received results in different methods is less if
the share of NaCl, in % is higher than 3%. If the share is less than 3%, the
difference in results rapidly increases, and the biggest difference is when
the share is less than 1%. This analysis was done according to the results
received by Volhard method, which is accepted as a standard method. As
Volhard method is in connection with cheese resolving by intense oxidation
means, azotic acid and potassium permanganate, obligatory in fume board
(hood), it is not a practical method. On the other hand, the potentiometric
method with usage of the chloride-selective electrode is very simple and
gives reliable and reproductive results. In case of a small content of NaCl,
in %, higher precision and accuracy of determination by chloride-selective
electrode can be obtained by indirect measurement of chloride-ions (by
standard addition method).
Sadrzaj NaCl (udeo Cl-jona, u %) analiziran je u sirevima domacih
proizvodjaca. Natrijum-hlorid u uzorcima sireva odredjivan je nakon ekstrakcije
hlorida rastvorom azotne kiseline. Koncentracija hlorid-jona je odredjivana
potenciometrijski, pomocu hlorid-selektivne elektrode i titrimetrijski
klasicnom Folhardovom metodom. Prema rezultatima odredjivanju sadrzaja NaCl, u
%, razlicitim metodama utvrdjeno je da se udeo NaCl, u %, krece u oblasti od
0,66 do 4,43% (odredjeno potenciometrijskim putem) odnosno od 0,97 do 4,72%
(odredjeno titrimetrijskim putem Folhardovom metodom). Odstupanja u dobijenim
rezultatima razlicitim metodama su utoliko manja ukoliko je udeo NaCl, u %,
veci od 3%. Ukoliko je udeo ispod 3%, razlika u rezultatima se rapidno
povecava, dok je najveca razlika ukoliko je udeo manji od 1%. Ova analiza
sprovedena je na osnovu rezultata koji su dobijeni Folhardovom metodom, koja
je |
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ISSN: | 1450-8109 2406-0968 |
DOI: | 10.2298/JAS1001065R |