Study of the Scavenger Properties of Manganese(lV) Oxide with Atomic Absorption Spectrometry. Determination of Microgram Quantities of Antimony, Bismuth, Lead, and Tin in Nickel Keith E. Burke The International Nickel Company, Inc., Paul D . Merica Research Laboratory, Sterling Forest, Suffern, N . Y . 10901
The accurate determination of less than 50 ppm of antimony, bismuth, lead, and tin in nickel generally requires a preliminary separation or concentration step. Manganese(lV) oxide i s used to concentrate these elements prior to their determination by atomic absorption spectrometry. Manganese(lV) oxide is a most effective scavenger when the concentration of nitric or perchloric acids is between 0.008 and 0.1M. A separation scheme has been devised which is applicable to the determination of 1 to 100 ppm of antimony, bismuth, lead, and tin in nickel. The precision for lead in nickel is k 2 ppm at the 20-ppm level.
THEACCURATE DETERMINATION Of less than 0.005 antimony, bismuth, lead, and tin is time consuming by the classical methods and difficult by direct instrumental techniques. In general, direct instrumental methods are subject to matrix interferences, and they may lack specificity and/or sensitivity. Direct spectrometry is generally sufficiently specific but it lacks sensitivity and requires special standardization to overcome possible matrix interferences. For certain elements, atomic absorption spectrometry is sometimes applicable t o the direct determination in the range of 0.0005 t o 0.01 %. However, antimony, bismuth, tin, and perhaps lead are among the metals which must be concentrated for a satisfactory determination by atomic absorption at this level. An ideal preconcentration scheme would isolate several elements from a variety of matrices (1). The ability of manganese(IV) oxide to preconcentrate ions has been known for about 65 years (2) and many useful analytical techniques are based on its scavenger properties. This property is discussed by Blumenthal(3). He added potassium permanganate t o a hot solution of manganese(I1) in dilute nitric acid, filtered off the resulting manganese(1V) oxide, and determined the coprecipitated antimony after dissolving the precipitate in dilute hydrochloric acid and hydrogen peroxide. Table I is a bibliography of analytical literature (2-26) (1) C. M. Davis, K. E. Burke, and M. M. Yanak, Adcari. X-ray Anal., 11, 56 (1968). (2) H. N. Stokes and J. R. Cain, J. Amer. Cliem. SOC.,29, 409 (1905); Bull. Nat. Birr. S m d . , 3, 115 (1907). (3) H. Blumenthal, Z . A m / . Cliem., 74, 33 (1928). (4) H. H. Willard and H. C. Fogg, J. Amer. Cliem. SOC.,59, 40 ( 1937). (5) P. B. Ganguly and N. R. Dhar, J . Phys. Chem., 26,702 (1922). (6) N. Kameyama and S . Makishima, J . Cliern. SOC. Jap., 36, 346 (1933). (7) K. B. Park and E. J. Lewis, ANAL.CHEM., 5, 182 (1933). (8) K. B. Park, ibid., 6, 189 (1934). (9) S. Kallmann and F. Pristera, ibid., 13, 8 (1941). (10) C. L. Luke, ibid., 15,626 (1943). (11) Y. Yao, ibid., 17, 114 (1945). (12) A. K. Babko and M. I. Shtokalo, Zacod. Lab., 21, 767 (1955). (13) E. B. J . MacNulty and L. D. Woollard, A m l . Cliim. Acta, 13, 64 (1955).
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which describes the scavenger properties of manganese(1V) oxide. The citations are arranged chronologically. Eleven elements including antimony, bismuth, lead, and tin are reported t o be coprecipitated with manganese(1V) oxide. Nearly all of the studies described in Table I were made with milligram quantities of the element being studied and with various quantities of manganese(1V) oxide. There is apparently a wide range of nitric acid concentrations under which the coprecipitation will take place quantitatively. In some instances, a double precipitation (6, 9,lO) has been applied to obtain complete recovery. Some question exists as t o which elements are quantitatively coprecipitated. The data in Table I suggest that antimony, bismuth, lead, and tin would be coprecipitated by manganese(1V) oxide if the concentration of nitric acid was 0.1M or less. In the present work, atomic absorption is used t o measure the effectiveness of manganese(1V) oxide as a scavenger at the microgram level. The hydrogen-argon-entrained air (H2AA) flame is used for the development work because of its low background in the ultraviolet and improved sensitivity for several elements (27). The H2AA flame is only useful for the analysis of solutions in which the total metal content is low (28, 29). The H2AA flame is used to evaluate the separation of microgram quantities of antimony, bismuth, lead, and tin with manganese(1V) oxide. An application of the separation to less than 100 ppm of antimony, bismuth, lead, and tin in nickel is given. EXPERIMENTAL
Apparatus. All investigations were performed with a Perkin-Elmer Model 303 atomic absorption spectrophotom(14) L. I. Katzin and R. W. Stoughton, J . Inorg. Nucl. Chem., 3, 229 (1956). (15) R. C. Roomy, Analyst, 82, 619 (1957). (16) M. Tsuiki, J. Electrochem. SOC.Jap., 29, 42 (1961). (17) E. S. Dzhaparidze and D. A. Gorishvili, Tr. Inst. Met,, Akad. Nauk Gruz. SSR, 13, 225 (1962). (18) D. Ogden and G. F. Reynolds, Analyst, 89, 538 (1964). (19) G. F. Reynolds and F. S . Tyler, ibid., 579. (20) American Society for Testing and Materials, “1965 Book of ASTM Standards, Part 32, Chemical Analysis of Metals,” ASTM, Philadelphia, Pa., 1965, p 244. (21) C. Bigliocca, F. Girardi, J. Pauly, E. Sabbioni, S. Meloni, and A. Provasoli, ANAL.CHEM.,39, 1634 (1967). (22) C. M. Pyburn and G. F. Reynolds, Analyst, 93, 375 (1968). (23) W. Feitknecht, Helu. Cliim. Acta, 28, 149 (1954). (24) E. A. Jenne, Aduan. Chem. Ser., 73, 337 1968. (25) A. A. Amsheev, Zacod. Lab., 34,789 (1968). (26) V. S. Biskupsky, Anal. Cliim. Acfa, 46, 1496 (1969). (27) H. L. Kohn and J. E. Schallis, A t . Absorption Newslett., 7 , 5 (1968). (28) K. E. Burke and C. H. Albright, Decelop. Appl. Spectrosc., 8, 33 (1969). (29) R. Smith, C. M. Stafford, and J. D. Winefordner, Anal. Chim. Acta, 42, 523 (1968).
ANALYTICAL CHEMISTRY, VOL. 42, NO. 13, NOVEMBER 1970
Table I. Annotated Bibliography of Manganese(1V) Oxide as a Scavenger Author (Ref) Subject WNOII Additional information Stokes and Cain (2) Collector for iron PH 7 Spectrophotometric method for iron Fe and In in Ga Procedure of Stokes and Cain ( 2 ) Willard and Fogg ( 4 ) PH 7 Ganguly and Dhar (5) Formation of MnOp Unknown Negatively charged MnOs Blumenthal(3) Sb in Cu Dilute Some Sn, As, Bi, Pb, Cu precipitated Karneyama and Makishima ( 6 ) Bi in Cu PH 5 Double precipitation Park and Lewis (7) Sb in Cu Slight acid 500-g sample Sb, Sn, Mo in Cu 0.016M MnOp BiOCl Park (8) Kallmann and Pristera (9) Sb, Sn, Bi in ores 0.07M mg, titrimetric and gravimetric As, Sb, Sn in Pb 0.07M Double precipitation Luke (10) Yao (11) Bi in Cu 0.02M Double precipitation Sb pH 1-7 No compound between Sb MnOz Babko and Shtokalo (12) MacNulty and Woollard (13) Small amounts Sb 1.2M pg, spectrophotometric Pa from Th, Zr, Hf 1-4M Pa concentrated 100-fold Katzin and Stoughton (14) Rooney ( 1 5 ) Sb in Cast Iron PH 1 H2S04 instead of HNO, Tsuiki (16) Bi, Sb, As in Pb 0.03-0.5M Polarographic Dzhaparidze and Gorishvili (17) Mn from Ni and Co Unknown Formation manganites Sb, Bi, Sn 0.06-1.2M mg., polarographic Ogden and Reynolds (18) Reynolds and Tyler (19) Sb, Sn in Pb 0.01-0.04M mg., polarographic Sb, Sn in Cu
