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Improvements to the Quantitative Assay of Nonrefractory Minerals for Fe(II) and Total Fe Using 1,10-Phenanthroline

Published online by Cambridge University Press:  28 February 2024

James E. Amonette  and
J. Charles Templeton
James E. Amonette
Affiliation:
Environmental and Health Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352
J. Charles Templeton
Affiliation:
Department of Chemistry, Whitman College, Walla Walla, Washington 99362
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Abstract

A method using 1,10-phenanthroline (phen) to quantify Fe(II) and total Fe in nonrefractory minerals was modified to improve the accuracy and precision and to eliminate the inconvenience of performing much of the analysis under darkroom conditions. Reagents were combined to minimize solution-handling errors, volumes of the reagent additions were determined gravimetrically and the acid-matrix solution was preheated to near-boiling before sample contact. The darkness requirement, which stems from the photoreduction of Fe(III) to Fe(II) in the presence of phen, was eliminated by the use of opaque amber-colored high-density-polyethylene bottles during the digestion step and for storage of the digestate and subsequent dilutions before Fe(II) analysis. Reduction of Fe(III) for total-Fe analysis was accomplished either by exposure to light from a Hg-vapor lamp or by reaction with hydroxylamine, NH2OH. Although the minimum periods required for adequate reduction ranged from 1.5 to 4 h, the optimum reduction periods were between 6 and 10 h. When standard samples containing Fe(II) and MnCl2 were digested and analyzed for total-Fe using the light treatment (with incidental heating to 35–45 °C), significant decreases and in some instances, oscillations, in absorptivity were obtained. Similar experiments with NH2OH, or with CrCl3 showed no effect. The absorptivity of most digestates stored in opaque bottles was stable for at least 2 weeks, although digestates with Mn concentrations above 3 µg mL−1 showed proportional decreases in absorptivity. Analysis of 8 geochemical reference materials by the modified method (using NH2OH) yielded excellent agreement with published values and a mean relative standard deviation of 0.6%. Total-Fe results obtained using the light treatment, however, were generally lower (∼2% relative) than the NH2OH values, although this difference decreased with longer irradiation periods. Use of NH2OH was deemed preferable because it was simpler, faster, minimized interferences from Mn and eliminated the need for specialized apparatus. Lastly, MICA Fe was shown to be unreliable as a primary reference material for Fe(II) determinations.

Keywords

1,10-PhenanthrolineBelousov-Zhabotinsky ReactionFe, Fe(II)Ferrous IronHydroxylamineOscillatory ReactionPhotoreductionTotal Iron
Type
Research Article
Information
Clays and Clay Minerals , Volume 46 , Issue 1 , February 1998 , pp. 51 - 62
Copyright
Copyright © 1998, The Clay Minerals Society

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References

Amonette, J.E. Khan, F.A. Scott, A.D. Gan, H. Stucki, J.W., Amonette, J.E. and Zelazny, L.W., 1994 Quantitative oxidation-state analysis of soils Quantitative methods in soil mineralogy, SSSA Miscellaneous Publication Madison, WI Soil Sci Soc Am. 83–113.CrossRefGoogle Scholar
Amonette, J.E. and Scott, A.D., 1991 Determination of ferrous iron in non-refractory silicate minerals—1. An improved semi-micro method Chem Geol 92 329–338 10.1016/0009-2541(91)90077-5.CrossRefGoogle Scholar
Bandemer, S.L. and Schaible, P.J., 1944 Determination of iron. A study of the o-phenanthroline method Ind Eng Chem Anal Ed 16 317–319 10.1021/i560129a013.CrossRefGoogle Scholar
Banerjee, S., 1974 Direct determination of ferrous iron in silicate rocks and minerals by iodine monochloride Anal Chem 46 782–786 10.1021/ac60342a037.CrossRefGoogle Scholar
Begheijn, L.T.h., 1979 Determination of iron(II) in rock, soil, and clay Analyst 104 1055–1061 10.1039/an9790401055.CrossRefGoogle Scholar
Blau, E., 1898 Über neue organische Metallverbindungen. Ein Beitrag zur Kenntniss der Metalliake—I Mittheilung. Monatsh Chem 19 647–683 10.1007/BF01517438.CrossRefGoogle Scholar
Bray, W.C., 1921 Periodic reaction in homogeneous solution and its relation to catalysis J Am Chem Soc 43 1262–1267 10.1021/ja01439a007.CrossRefGoogle Scholar
Degn, H., 1972 Oscillating chemical reactions in homogeneous phase J Chem Ed 49 303–307 10.1021/ed049p302.CrossRefGoogle Scholar
Epstein, I.R. Kustin, K. De Kepper, P. and Orban, M., 1983 Oscillating chemical reactions Sci Am 248 112–123 10.1038/scientificamerican0383-112.CrossRefGoogle Scholar
Fortune, W.B. and Mellon, M.G., 1938 Determination of iron with o-phenanthroline. A spectrophotometric study Ind Eng Chem Anal Ed 10 60–64 10.1021/ac50118a004.CrossRefGoogle Scholar
French, W.J. and Adams, S.J., 1972 A rapid method for the extraction and determination of iron(II) in silicate rocks and minerals Analyst 97 828–831 10.1039/an9729700828.CrossRefGoogle Scholar
Komadel, P. and Stucki, J.W., 1988 Quantitative assay of minerals for Fe2 and Fe3 using 1,1 O-phenanthroline: III. A rapid photochemical method Clays Clay Miner 36 379–381 10.1346/CCMN.1988.0360415.CrossRefGoogle Scholar
Lalonde, A.E. Rancourt, D.G. and Ping, J.Y., 1997 Accuracy of ferric/ ferrous determinations in phyllosilicates: A comparison of Mössbauer and wet-chemical methods. Program with Abstracts A45.Google Scholar
Nicolis, G. and Portnow, J., 1973 Chemical oscillations Chem Rev 73 365–384 10.1021/cr60284a003.CrossRefGoogle Scholar
Noyes, R.M. and Field, R.J., 1974 Oscillatory chemical reactions Ann Rev Phys Chem 25 95–119 10.1146/annurev.pc.25.100174.000523.CrossRefGoogle Scholar
Potts, P.J. Tindle, A.G. and Webb, P.C., 1992 Geochemical reference material compositions Boca Raton, FL CRC Pr..Google Scholar
Roth, C.B. Jackson, M.L. Lotse, E.G. and Syers, J.K., 1968 Ferrous-ferric ratio and CEC changes on deferration of weathered micaceous vermiculite Israel J Chem 6 261–273 10.1002/ijch.196800036.CrossRefGoogle Scholar
Saywell, L.G. and Cunningham, B.B., 1937 Determination of iron. Colorimetric o-phenanthroline method Ind Eng Chem Anal Ed 9 67–69 10.1021/ac50106a005.CrossRefGoogle Scholar
Schafer, H.N.S., 1966 The determination of iron(II) oxide in silicate and refractory minerals—I. A review Analyst 91 755–762 10.1039/an9669100755.CrossRefGoogle Scholar
Schilt, A.A., 1969 Analytical applications of 1,1 O-phenanthroline and related compounds Oxford, UK Pergamon Pr..Google Scholar
Shapiro, L., 1960 A spectrophotometric method for the determination of FeO in rocks .Google Scholar
Stucki, J.W., 1981 The quantitative assay of minerals for Fe+2 and Fe+3 using 1,10-phenanthroline: II. A photochemical method Soil Sci Soc Am J 45 638–641 10.2136/sssaj1981.03615995004500030040x.CrossRefGoogle Scholar
Stucki, J.W. and Anderson, W.L., 1981 The quantitative assay of minerals for Fe+2 and Fe+3 using 1,1 O-phenanthroline: I. Sources of variability Soil Sci Soc Am J 45 633–637 10.2136/sssaj1981.03615995004500030039x.CrossRefGoogle Scholar
Van Loon, J.C., 1965 Titrimetric determination of the iron(II) oxide content of silicates using potassium iodate Talanta 12 599–603 10.1016/0039-9140(65)80074-1.CrossRefGoogle Scholar
Walden, G.H. Hammett, L.P. and Chapman, R.P., 1931 A reversible oxidation indicator of high potential especially adapted to oxidimetric titrations J Am Chem Soc 53 3908 10.1021/ja01361a508.CrossRefGoogle Scholar
Wilson, A.D., 1955 A new method for the determination of ferrous iron in rocks and minerals Bull Geol Surv Eng 1955 56–58.Google Scholar
Wood, P.M. and Ross, J., 1985 A quantitative study of chemical waves in the Belousov-Zhabotinsky reaction J Chem Phys 82 1924–1936 10.1063/1.448376.CrossRefGoogle Scholar
Zhabotinsky, A.M., 1964 Periodic process of the oxidation of malonic acid in solution (study of kinetics of Belousov’s reaction) Biofizika 9 306–311.Google Scholar
Zhabotinsky, A.M., 1964 Periodic liquid phase oxidation reactions Dokl Akad Nauk SSSR 157 392–395.Google Scholar