(4)Detre, D e u f . m e , / . I t ~ u c h c h r . ,49, Y86 (19231. (5) Doiiau, ~11orcatsh..29, 333 (19081. (6) Emich-Schneider, "Jlicrorheriiical Laboratory Jfanual," p . 39 e t seci., S e n . I-ork. John Wile>- tY3 Son.-, 1933.
((7)Itlid., p. (8) Ibirl., g . (9) Ibid., 11. (10) Ibid., r J . i l l ) Ibid., g .
32. 40. 61.
80.
81. I 12) Ibid.,p. 112. (13) Ibid., p. 116. -: (13) Ibid., p. 127. (15) Ibid., p. 136. (16) Ibid., p. 135. (17) Feist, Be,,., 35, 1559 (19021. (18) Fischer. Ber., 44, 129 ( 1 9 1 1 ' . (19) Graehe. f h i d . , 17, 1178 (1884;. 120) Hays, H a r t , a n d Gustai-son, ISD. ESG. CHEAI.,-'.nd. 3 E L . 8. 286 (1936). FI~;LTRE 5 . S C H L I E RD E ~E T E E ~ I I ~ . OF ~ TSOLI-RILITT I~S OF S ~ L I W (21) I < m ~ m ."Qualitatire Organic Analysis," Sen. T o r k , John W l e y & Sons, 1922. (22) Kofler and Hilbck, Mikrocizernie, 9, 38 (1931~. the substance is soluble, either ascending or dewending; nothing ( 2 ' 3 ) Mason, Cizemistru & ~ n d f t s t r y44, , 677 (1925). ( 2 4 Pregl-Fyleman, "Quantitative Organic 3Iicroaniilysis," 2nd can be observed if the substance is insohthle. ed., p. 217, London, J. a n d A . Chiirchill, 1930.
_ > I
The schlieren permit a very sen6itiYe and rapid tleteriiiiriation of the solubility of a suhstance. The authors are working a t present with a large nuiiiber of compounds, 1)oth as solutes and solvents. T h e resnlts of this rrork nil1 be reported in a subsequent paper.
Literature Cited (1) Barkenbus a n d Baker, IXD. ESQ. C H m f . , Anal. E d . , 9, 136 (1937). (2) Benedetti-Piohler a n d Spikes, "Introduction t o t h e Microtechnique of Inorganic Qualitatire .Inalysis," Douglaston, N. T., Microchemical Service, 1935. ( 3 ) Dennis and Shelton, J . Ani. Chern. SOC.,52, 3128 (1930).
(26) Ibid., D. 222. ( 2 7 ) Rassoa, 2. a n o i y . Cherrr., 114, 117 (1920). (28) Schneider a n d Saschek. Rochester Meetlne, Seitteriiber, 1937. (29) Shead, ISD.ESG. CHESI.,Anal. E d . , 9, 496 (1937). (30) Shriner and Fuson, "Systematic Identification of Organic Coninonnds." New T o r k . J o h n TYilev & Sons. 1935. (31) Stiudinger, " I n t r o d u c t i o n ' t o Qualitati\-e Organic .In:tlysis," Berlin, Julius Springer, 1923. 132) Willard a n d Blank, J . Chern. Education, 10, 109 (1933). (33) Worrnley, "Microcheiriistry of Poisons," Philadelphia, J. B. Lippincott, 1867. RECEIVED September 2 5 , 1937. Presented before the Microchemical Section at the 94th Meeting of the American Chemical Society, Rochester, N. P., September 6 to 10. 193i.
Qualitative Separations on a Micro Scale Analysis of the Alkali Group A . A. BENEDETTI-PICHLER i N D JAMES T. BRYANT Chemical Laboratories of W'aqhington Square College, Xew York University, New York. N. Y.
A
S I X FORhIER investigations of this series, a n attempt was made to adhere in t h e transposition to the milligram
scale to the procedure of Noyes and Bray ( 7 ) RS closely a. advisable. A brief survey of the outline of the authors' final scheme which is presented herewith will nevertheless reveal considerable deviations. T h e principal change consists in the substitution of chloroplatinic acid for perchloric acid as a reagent for the separation of potasqium, rubidium, ani1 ceiium from sodium and lithium. The decision on chloroplatinic acid is permissible because of the small quantities of reagents required on the milligram scale. The use of this reagent is preferable from the technical viewpoint, since the chloroplatinatea obtained call be easily converted into chlorides by siniple ignition. Additional changes in the analysis of the potassium subgroup consist essentially of a different arrangement of the order in which the reagents used b y S o y e s and Bray are applied. The mixture of the chlorides is first treated with iodobismuthous acid which enables a n immediate detection of the cesium if present in quantities larger than 5 pg. The immediate isolation of cesium simplifies the remainder of the procedure for the analysis of the potassium subgroup, which now may limit itself essentially to the separation of
potassium aiid rubidium. The triple chlorides with gold and silver, introduced by Elriich as slide tests, are used as confirmatory tebts for rubidium and cesium. As for the working technic, both the tapered (Emich) and the cylindrical (Spikes. 4 ) microconeq are used. Most of the work is performed in Eniich cones, and the Spikes cones are used only in the compaiison of the volumes of precipitates for the estimation of the quantity of the various metals ( 3 ) . In part of the work use is made of cones of clear fused quartz. Experience has shown that sodium is always found in blank analyses, when cones of soft 01 Pyrex glaqs are used for the ignition of precipitates or residues.
Procedure (7 I Filtrate F l 5 l from the ( N H I ) ~ C OgJr o u p HCI BaC12
+
+
Filtrate F160: (NHdzC03 I Filtrate F161: Evaporate, ignite the residue
BabO,. reject
+
Residue Ri61: + HzPtCle + alcohol _ _
