Elektrolytische abscheidung im hydrodynamischen system von ng-mengen eisen,kobalt, zink und wismut im graphitrohr

An electrolysis cell is described, which allows the constant-current deposition of ng amounts of elements from solutions containing less than 10 p.p.b. with yields above 98% in relative short times. Separations from elements which cannot be electrolytically deposited (e.g. Be) are possible. The electrolyte (40 ml) is cycled through a cylindrical cathode of ultrapure graphite (length 9 mm, i.d. 2.8 mm) by a PTFE-pump at 20–30 ml min^-1. A Pt/Ir (diam. 1.5 mm) anode is centered in the cathode space. The graphite cathode can be used directly for a sensitive determination of the deposited elements, e.g. by flameless a.a.s., o.e.s. (i.c.p., c.m.p.) and n.a.a. Radiotracers (⁵⁹Fe, ⁶⁰Co, ⁶⁵Zn and ²⁰⁷Bi) were used to determine the deposition yields, which were found to be optimal in NH₄F electrolytes (2–10%) of pH 5–6.