Nitroso disulfonate ions

Preconcentration of trace nickel with the ion pair of disodium l-nitroso-2-naphthol-3,6-disulfonate and tetradecyldimethylbenzylammonium chloride on microcrystalline naphthalene (or by the column method) was applied prior to the determination of Ni in standard alloy, steel and biological samples by derivative spectrophotometry [1]. The detection limit of 10 ppb was repotted. 

Chromotropic acid (l,8-dihydroxynaphthalene-3,6-disulfonate) reacts with zirconium(IV) to form a 1 1 complex. The apparent equilibrium constant for this system at pH 2.0 and at a metal ion concentration of 5 X 10 M n 0. M KCl, was calculated to be logAzr = 3.63 (466). The initial report (98) of little or no reaction appears to be incorrect. A nitroso derivative of this ligand reacts with zirconium(IV) to give a red-violet precipitate in weak acid solution (535). 

C10H7O8NS Metal ion 2 Equilibrium 2-Nitroso-l -naphthol-4,7-disulfonic ac ... 

Nitroso-R salt is the disodium salt of a-nitroso-/ff-naphthol-disulfonic acid. This reagent reacts with Co in the same manner as a-nitroso-)5-naphthol, but it is water-soluble. A highly sensitive spot test is based on the formation of the red cobalt complex of this reagent on an ion-exchange resin. 

---