Polarographic and voltammetric determination of 4,4′-bis[(4-diethanolamino-6-(2,5-disulfophenylamino)-1,3,5-triazin-2-yl) amino]stilbene-2,2′-disulfonic acid

The polarographic and voltammetric behaviour was studied for 4,4′-bis[(4-diethanolamino-6-(2,5-disulfophenylamino)-1,3,5-triazin-2-yl) amino]stilbene-2,2′-disulfonic acid, which is the basis of many commercial optical whitening agents. The optimum conditions were found for quantitation of this substance in tetraethylammonium bromide solutions in dimethylformamide containing 5% (v/v) water using TAST polarography, differential pulse polarography, linear sweep voltammetry at a hanging mercury drop electrode, and differential pulse voltammetry at a hanging mercury drop electrode over the concentration regions of 100-500, 10-500, 10-500, and 1-100 μmol 1^-1, respectively. The practical applicability of the new analytical methods to the determination of the substance in technical products was verified.