METHOD FOR TUBIDIMETRIC DETECTION OF IODIDE IONS Russian patent published in 2009 - IPC G01N31/02 G01N21/59 

FIELD: chemistry.

SUBSTANCE: invention relates to analytical chemistry, and enables determination of content of iodide ions in different objects, for example water (drinking, surface, artesian, packaged mineral water etc), in food products etc. The method is based on moving iodide ions into a partially soluble compound AgI (Conductance_AgI=1.1 10^-6). AgI is precipitated in the presence of a 25% ammonia solution (pH=9-11), which prevents precipitation of AgCl, which turns into a complex [Ag(NH₃)₂]⁺ ion. To stabilise the suspension, alcohol is added as a stabiliser. Optical density of the obtained suspension of silver iodide is then measured on a spectrometre. Measurements are taken at wavelength of 380 nm, which corresponds to maximum absorption of the given suspension. A calibration curve, obtained using standard KI solutions, is used to find content of iodide ions in the concentrate. Further, concentration of iodide ions in the analysed samples is then determined taking into account concentration level.

EFFECT: simple photometric method for determining concentration of iodide ions, cutting on the number of operations and time for determination, as well as non-use of toxic substances.

1 tbl, 1 ex