Turbidimetric method of determination of sulfates’ microquantity to ascertain a falsification of Borjomi mineral water

Author: Nino Takaishvili
Co-authors: Guram Supatashvili
Keywords: Sulfates, Turbidimetric method, Borjomi mineral water
Annotation:

Turbidimetric method of determination of sulfates microquantity can be successfully used in order to ascertain a falsification of Borjomi mineral water. The most common method of Borjomi falsification is the insertion of some components (NaHCO3, NaCl, CO2 etc.) into ordinary drinking water. There are several options for identification of falsified Borjomi water (determination of microcomponents, complete analysis) that is labor-consuming and long-time process. For this purposes we can use sulfate-ion as controlling component. This selection is justified by the fact that artificial control of SO42- content is virtually impossible. For determination of SO42- in mineral waters of carbonate class 100,0 ml of sample were preliminary neutralized with 1:1 HCl, were heated up to boiling for CO2 removal, then were cooled, filled up to 100,0 ml and afterwards SO42- was determined turbidimetrically in the aliquot (5,0ml). It is possible to insert surface active substance (synthanol DC-10) into a composition of precipitating agent, which increases by 30-50% optical density of BaSO4 suspension. According to Borjomi water standards a concentration of SO42- should be < 10 mg/l (usually it equals to 2-4 mg/l), while in falsified samples, if they are prepared from drinking water (Natakhtari or other), concentration of SO42- is more than 20-30 mg/l.

Lecture files:

Turbidimetric method of determination of sulfates’ microquantity to ascertain a falsification of Borjomi mineral water [en]
მიკრორაოდენობა სულფატების განსაზღვრის ტურბიდიმეტრული მეთოდი ბორჯომის მინერალური წყლის ფალსიფიცირების დასადგენად [ka]