Paper chromatography of inorganic ions

ANAL\-TIC.4

132

CHIMICA

ACTA

VOL.

11

(19.54)

PAPER CI-IROMA’TOGRAl?HY 017 INORGANTC IONS VII. ‘I’l-IE PAPER CHROMATOGRAPWY OF GERMANrUM

In a recent rcvicw of the applications of chromatogral>hy to radiochemistry’ WC wcrc able to discuss tlic significance of the I<, value of metals as a gcncral property and for the solvent butanol snturatcd with IN HCl, the RI.- values of all 13 group clcments of the periodic table cxccpt Gc were taken into considcration. Ge, being an exceedingly rare clement, had not been studied. It was rcccntly suggested to us by Madame I-I. IANGEVIN to study the separation of germanium Gc - As with a view to preparing carrier-free As by bombardment metal. Thus this work was undertaken both to fill the gap in the XF table of clcments and to dcvclop a method for the separation of Gc and As. In the preparation of a solution of Gc(IV) from Gc metal we used a fusion with NaOl-I, as the attack with aqua rcgia does not proceed quickly and after several hours the solution obtained does not permit dctcction of Ge. The fusion mixture was dissolved in a small quantity of water and an cxccss of aqua regia added to cnsucc conversion to Gc(IV). The spots of Gc may bc dctcdtcd in several ways: I) Spraying with ammonium molybdatc solution followed by sodium stannite in giV NaOH produces a sensitive blue reaction. In acid medium no blue colour could bc obtained cithcr with bcnzidinc nor with stannous chloride as reductant. z) S-hydrosyquinolinc products in ultraviolet light a pale green fluorescent spot. This reaction is best carried out by dipping the paper strip after drying into an alcoholic ammoniacal solution of S-hydroxyquinolinc and viewing immcdiatcly under ultraviolet light. 3) The paper is csl~osccl to 14,s furncs and dried in a current of warm air till it clots not smell of H,S. In this trcatmcnt both Ge(lV) and As(III) form sulphides; the first colourless and the second pale yellow. If the paper strip is subsequently bathed in a N/IOO solution of AgNO, the more insoluble black Ag,S is formed on the spots whcrc the Gc and As sulphidcs arc situated. Thus black spots on a white backbTound arc distinctly visible for about fifteen minutes after which time there is a darkening of the paper. The spots of the Gc solution prepared by fusion as mentioned above wcrc ~iCf&‘WX p.

133.

VOL.

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PAPER

CMROMATOGRAPIXY

OF

INORGANIC

IOSS

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placed on Whatman No. I sheets and developed by the ascending method with butanol saturated with IN HCI. The pure solution yielded spots with Z?F 0.35 - o.40 with reference to the water front, and 0.25 - 0.29 with reference to the first liquid front. When shown up with S-hydroxyquinoline a spot due to Ni (R, 0.1) and one weak spot due to Fe (X, 0.15) were also revealed and are due to Ni and Fc introduced by fusing in a nickel crucible. A solution of arsenite and arsenate mixed with the germanium solution produced three well separated bands As(V) I=?,.-0.84, As(III) R, 0.5” and Ge(IV) lir 0.26. Thus an adequate 12, difference for radiochemical separation exists between Ge and As. SU&IbIAR\Gcrmaniuni(IV) chromatography

(IV)

bc scparatcd from As and many other clcmcnts by palwr ma with Y,utanol saturated with IN HCI. The iZr value of germanium

is 0.25 - 0.29.

Lc gcrmanium(IV) par chromatographie gcrmanium(IV) cst

peut ctrc s+-xxr& de I’arscnic ct de bcaucoup d’autrcs dl&mcnts sur papier, au moyen de butanol saturd de HCl N. Lc A’z: du 0.25 - 0.29.

IDas Gcrmanium(IV) kann vom Papierchromatoqaphie abgetrcnnt gesAtti@ ist. Fir Gcrmamum(IV)

1 M. LEDlxzEu, Cowcg9to Rome, rg53, dei Lincet,

Arsen und von viclen andern Elcmentcn werdcn mit Hllfe von Uutanol, das mit ist IZx: 0.25 - 0.2g.

srrlle Ira5fovrnaeto9tt In press.

radiocfbttntche

deCla Accadetrtia

Received

March

durch I-ICI hr

wtzio?talc I I th,

1g54