ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Photometric microtitrations .8. Mercurimetric determination of cyanide using naphthylazoxine 6s as indicator

V. Říha, Pham-Vu Quat, V. Mach, and S. Kotrlý

Department of Analytical Chemistry, University of Chemical Technology, CS-532 10 Pardubice

Abstract: Naphthylazoxine 6S was evaluated as a suitable metal indicator for the determination of cyanide in the concentration range 5x10^-4 to 1x10^-6 mol dm^-4 The use of photometric indication permitted titration with a dilute standard solution of mercury(II) Perchlorate (с = 0.001 mol dm^-3 to 0.01 mol dm^-3 ). Under optimum conditions (pH range 5.0 to 5.5, I= 0.05 mol dm^-3  , c(ind)= 10^-5 mol dm^-3 ; λ= 530 nm), precise results were obtained ( s_r / % ≤ 1). A thin layer of paraffin oil on the surface prevented loss of HCN during titration so that systematic deviations, with respect to the reference Liebig—Déniges titration with turbidimetric indication, were insignificant (≲1%) . Cyanide can be titrated in presence of an equal amount of chloride or thiocyanate (at pH≈6) ; bromide interferes, while iodide is titrated with cyanide.

Full paper in Portable Document Format: 411a57.pdf

Chemical Papers 41 (1) 57–68 (1987)