Luminescence titration method

Electrophoretic and isotachoelectrophoretic techniques are gaining in popularity in soil analysis with applications to polyaromatic hydrocarbons, polychlorobiphenyls, tetrahydrothiophene and triazine herbicides, Paraquat and Diquat and growth regulators. Other lesser-used techniques include spectrophotometric methods (five determinants), spectrofluorimetric methods (two determinants), luminescence methods (one determinant), titration methods (one determinant), thin-layer chromatography (five applications), NHR spectroscopy (two applications) and enzymic immunoassays (one determinant). 

Titrimetric luminescence methods record changes in the indicator emission of radiation during titration. This change is noted visually or by instruments normally used in luminescence analysis. Most luminescence indicators are complex organic compounds which are classified into fluorescent and chemiluminescent, compounds according to the type of emission of radiation. As in titrimetry with adsorption of colored indicators, luminescence titration makes use of acid-base, precipitation, redox, and complexation reactions. Unlike color reactions, luminescence indicators enable the determination of ions in turbid or colored media and permit the detection limit to be lowered by a factor of nearly one thousand. In comparison with direct luminescence determination, the luminescence titrimetric method is more precise. 

In order to study the mobility of elements of crosslinked structure of CP, it is suitable to use their microdisperse forms [30-35]. On the one hand, in potentiome-tric titration the equilibrium is quickly attained for these forms and on the other hand the effect of light scattering in spectral methods of investigation (e.g., polarized luminescence) can be greatly decreased. 

Fig. 3. Luminescence methods of determining elements developed in the recent decade. Fluorescence of complexes with organic ligands - native luminescence of complexes with inorganic and organic ligands (proceeding of determination are developed - , possibility of determination are mentioned - LI) chemiluminescence - titration with luminescence indicators - S...

Complexes of Cr and Cr are produced in the photoprocess leading to the hardening of chromated poly(vinyl alcohol). Methods have also been reported for the determination of chromium by a luminescence method and by a photochemical titration procedure. ... 

---