1、Designation: E394 09E394 15Standard Test Method forIron in Trace Quantities Using the 1,10-PhenanthrolineMethod1This standard is issued under the fixed designation E394; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of l
2、ast revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the determination of iron in the range from 1 to 100 g.1.2 This test method is intended to be
3、general for the final steps in the determination of iron and does not include proceduresfor sample preparation.1.3 This test method is applicable to samples whose solutions have a pH less than 2. It is assumed that the pH is adjusted towithin this range in the sample preparation.1.4 Review the curre
4、nt material safety data sheets (MSDS) Safety Data Sheets (SDS) for detailed information concerningtoxicity, first-aid procedures, handling, and safety precautions.1.5 The values given in SI units are the standard. Values in parentheses are for information only.1.6 This standard does not purport to a
5、ddress all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1193 Specifi
6、cation for Reagent WaterE60 Practice for Analysis of Metals, Ores, and Related Materials by SpectrophotometryE180 Practice for Determining the Precision of ASTM Methods for Analysis and Testing of Industrial and Specialty Chemicals(Withdrawn 2009)3E200 Practice for Preparation, Standardization, and
7、Storage of Standard and Reagent Solutions for Chemical AnalysisE275 Practice for Describing and Measuring Performance of Ultraviolet and Visible Spectrophotometers3. Summary of Test Method3.1 This test method is based upon a photometric determination of the 1,10-phenanthroline complex with the iron(
8、II) ion. Thesample is dissolved in a suitable solvent and the iron is reduced to the divalent state by the addition of hydroxylaminehydrochloride. The color is then developed, by the addition of 1,10-phenanthroline. After a short reaction period, the absorbanceof the solution is measured at approxim
9、ately 510 nm using a suitable photometer. The absorbance of the solution, once the coloris developed, is stable for at least several months.4. Significance and Use4.1 This test method is suitable for determining trace concentrations of iron in a wide variety of products, provided thatappropriate sam
10、ple preparation has rendered the iron and sample matrix soluble in water or other suitable solvent (see 10.1 andNote 65).1 This test method is under the jurisdiction of ASTM Committee E15 on Industrial and Specialty Chemicals and is the direct responsibility of Subcommittee E15.01 onGeneral Standard
11、s.Current edition approved April 1, 2009Nov. 1, 2015. Published May 2009January 2016. Originally approved in 1970. Last previous edition approved in 20042009 asE394 00E394 09.(2004). DOI: 10.1520/E0394-09.10.1520/E0394-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contac
12、tASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.This document is not an ASTM standard and is intended
13、 only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current v
14、ersionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.2 This test method assumes that th
15、e amount of color developed is proportional to the amount of iron in the test solution. Thecalibration curve is linear over the specified range. Possible interferences are described in Section 5.5. Interferences5.1 Fortune and Mellon4 have made a comprehensive study of the interferences of various i
16、norganic ions in this determination.Table 1 and Table 2, taken from their report, show the effects of various cations and anions on the determination of 2.0 g/g (ppm)iron. If the maximum level of 500 g/g (ppm) does not interfere, it is very likely that the ion will not interfere in any quantity.The
17、data were obtained under slightly different conditions than those specified in the present test method, but the interferencesshould be similar. For a more detailed description of interferences, the original literature should be consulted.5.2 Aldehydes, ketones, and oxidizing agents interfere by cons
18、uming the hydroxylamine hydrochloride added as a reducingagent.6. Apparatus6.1 Photometer, capable of measuring light absorption at 510 nm and holding a 5-cm or 1-cm cell. Check the performance ofthe photometer at regular intervals according to the guidelines given in Practice E275 and the manufactu
19、rers manual.NOTE 1If a filter photometer is used, a narrow band filter having its maximum transmission at 480 to 520 nm should be used. A discussion ofphotometers and photometric practice is given in Practice E60.6.2 Absorption Cells, 5-cm or 1-cm light path.7. Reagents and Materials7.1 Purity of Re
20、agentsUnless otherwise indicated, it is intended that all reagents shall conform to the specifications of theCommittee onAnalytical Reagents of theAmerican Chemical Society, where such specifications are available.5 Other grades maybe used, provided it is first ascertained that the reagent is of suf
21、ficiently high purity to permit its use without lessening the accuracyof the determination.7.2 Purity of WaterUnless otherwise indicated, references to water shall be understood to mean Type II reagent water asdefined in Specification D1193.7.3 Hydroxylamine Hydrochloride Solution (100 g/L)Dissolve
22、10 g of hydroxylamine hydrochloride (HONH2 HCl) inapproximately 60 mL of water, filter, and dilute to 100 mL.67.4 Iron, Standard Solution (1 mL = 0.01 mg Fe)7 (Note 2)Dissolve 0.1000 g of iron wire in 10 mLof hydrochloric acid (HCl,1 + 1) and 1 mL of bromine water. Boil until the excess bromine is r
23、emoved. Add 200 mL of HCl, cool, and dilute to 1 L in avolumetric flask. Dilute 100 mL of this solution to 1 L.NOTE 2As an alternative, the standard iron solution may be prepared by weighing exactly 0.7022 g of iron (II) ammonium sulfate hexahydrate(FeSO4(NH4)2SO46H2O, minimum purity, 99.5 %) in 500
24、 mL of water containing 20 mL of sulfuric acid (H2So4, sp gr 1.84) and diluting to 1 L withwater. Dilute 100 mL of this solution to 1 L.7.5 1,10-Phenanthroline Solution (3 g/L)Dissolve 0.9 g of 1,10-phenanthroline monohydrate in 30 mLof methanol and diluteto 300 mL with water.6,87.6 Ammonium Acetate
25、Acetic Acid SolutionDissolve 100 g of ammonium acetate (CH3COONH4) in about 600 mLof water,filter, add 200 mL of glacial acetic acid to the filtrate, and dilute to 1 L with water.68. Sampling8.1 Because this is a general test method for the final steps in determining iron, specific procedures for sa
26、mple preparation arenot included (see 1.3, 4.1 and 4.2).9. Calibration9.1 By means of suitable pipets or a buret, transfer 0 (reagent blank), 2, 4, 6, 8, and 10 mL, respectively, of the standard ironsolution to each of six 100-mL, glass-stoppered graduated cylinders.volumetric flasks. These cylinder
27、sflasks contain 0, 20, 40, 60,80, and 100 g of iron, respectively. Dilute the contents of each cylinderflask to 80 mL with water. Develop the color and measurethe absorbance of each calibration standard as described in 10.3 and 10.4.4 Fortune, W. B., and Mellon, M. G., Industrial and Engineering Che
28、mistry, Analytical Edition, IENAA Vol 10, 1938, pp. 6064.5 Reagent Chemicals, American Chemical Society Specifications, , American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed bythe American Chemical Society, see Analar Standards for Laboratory Chemicals, B
29、DH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC),(USP), Rockville, MD.6 This solution is also described in Practice E200.7 This solution is used for calibration only.8 Frederick, G., and Richter, F. P., Phenanthrolines
30、 and Substituted Phenanthroline Indicators, GFS Publication No. 205, 1944 (no charge).E394 152TABLE 1 Effect of Cations on the Determination of 2 g/g (ppm) IronIon Added As Maximum Added WithoutInterference, g/g (ppm) Applicable pH RangeAluminum AlCl3 500 2.03.0Ammonium NH4Cl 500 2.09.0Antimony SbCl
31、3 30 3.09.0Arsenic As2O5 500 3.09.0Arsenic As2O3 500 3.09.0Barium BaCl2 500 3.09.0Beryllium Be(NO3)2 500 3.05.5Bismuth Bi(NO3)3 .A .ACadmium Cd(NO3)2 50 3.09.0Calcium Ca(NO3)2 500 2.09.0Chromium Cr2(SO4)3 20 2.09.0Cobalt Co(NO3)2 10 3.05.0Copper Cu(NO3)2 10 2.54.0Lead Pb(C2H3O2)2 500 2.09.0Lithium L
32、iCl 500 2.09.0Magnesium Mg(NO3)2 500 2.09.0Manganese MnSO4 500 2.09.0Mercury HgCl2 1 2.09.0Mercury Hg2(NO3)2 10 3.29.0Molybdenum (NH4)6Mo7O24 100 5.59.0Nickel Ni(NO3)2 2 2.59.0Potassium KCl 1000 2.09.0Silver AgNO3 .A .ASodium NaCl 1000 2.09.0Strontium Sr(NO3)2 500 2.09.0Thorium Th(NO3)4 250 2.09.0Ti
33、n H2SnCl6 20 3.06.0Tin H2SnCl4 10 2.06.0Tungsten Na2WO4 10 2.59.0Uranium UO2(C2H3O2)2 100 2.06.0Zinc Zn(NO3)2 10 2.09.0Zirconium Zr(NO3)4 50 2.09.0TABLE 1 Effect of Cations on the Determination of 2 g/g (ppm) IronIon Added As Maximum Added WithoutInterference, g/g (ppm) Applicable pH RangeAluminum A
34、lCl3 500 2.03.0Ammonium NH4Cl 500 2.09.0Antimony SbCl3 30 3.09.0Arsenic As2O5 500 3.09.0Arsenic As2O3 500 3.09.0Barium BaCl2 500 3.09.0Beryllium Be(NO3)2 500 3.05.5Bismuth Bi(NO3)3 .A .ACadmium Cd(NO3)2 50 3.09.0Calcium Ca(NO3)2 500 2.09.0Chromium Cr2(SO4)3 20 2.09.0Cobalt Co(NO3)2 10 3.05.0Copper C
35、u(NO3)2 10 2.54.0Lead Pb(C2H3O2)2 500 2.09.0Lithium LiCl 500 2.09.0Magnesium Mg(NO3)2 500 2.09.0Manganese MnSO4 500 2.09.0Mercury HgCl2 1 2.09.0Mercury Hg2(NO3)2 10 3.29.0Molybdenum (NH4)6Mo7O24 100 5.59.0Nickel Ni(NO3)2 2 2.59.0Potassium KCl 1000 2.09.0Silver AgNO3 .A .ASodium NaCl 1000 2.09.0Stron
36、tium Sr(NO3)2 500 2.09.0Thorium Th(NO3)4 250 2.09.0Tin H2SnCl6 20 3.06.0Tin H2SnCl4 10 2.06.0Tungsten Na2WO4 10 2.59.0Uranium UO2(C2H3O2)2 100 2.06.0Zinc Zn(NO3)2 10 2.09.0Zirconium Zr(NO3)4 50 2.09.0A Must be completely absent because of precipitation.E394 1539.2 Plot, on linear graph paper, the Pl
37、ot the results in an X-Y graph, with the micrograms of iron as a function of absorbance.onthe x-axis and the respective absorbances on the y-axis. Visually evaluate the calibration graph obtained for linearity and for theabsence of obvious outlying values. If so, proceed to the next step. If not, in
38、vestigate for an assignable cause.NOTE 3If the photometer readings are percent transmittance, they may be plotted on semi-log paper or converted to absorbance as follows:9.2.1 Establish a linear regression function from the calibration data using the statistical method of least squares, for example,
39、with the aid of a spreadsheet. The formula for a linear calibration function is:y 5a1bx (1)where:b = slope of calibration line, anda = intercept.A 5logS100T D (1)TABLE 2 Effect of Anions on the Determination of 2 g/g (ppm) IronIon Added As Maximum Added WithoutInterference, g/g (ppm) Applicable pH R
40、angeAcetate NaC2H3O2 500 2.09.0Tetraborate Na2B4O7 500 3.09.0Bromide NaBr 500 2.09.0Carbonate Na2CO3 500 3.09.0Chlorate KClO3 500 2.59.0Chloride NaCl 1000 2.09.0Citrate H3C6H5O7 500 2.09.0Cyanide KCN 10 2.09.0Dichromate K2Cr2O7 20 2.59.0Fluoride NaF 500 4.09.0Iodide KI 500 2.09.0Nitrate KNO3 500 2.0
41、9.0Nitrite KNO2 500 2.59.0Oxalate (NH4)2C2O4 500 6.09.0Perchlorate KClO4 100 2.09.0Phosphate (NH4)2HPO4 20 2.09.0Pyrophosphate Na4P2O7 50 6.09.0Silicate Na2SiO3 100 2.04.5Sulfate (NH4)2SO4 500 2.09.0Sulfite Na2SO3 500 2.09.0Tartrate (NH4)2C4H9O6 500 3.09.0Thiocyanate KCNS 500 2.09.0Thiosulfate Na2S2
42、O3 500 3.09.0TABLE 2 Effect of Anions on the Determination of 2 g/g (ppm) IronIon Added As Maximum Added WithoutInterference, g/g (ppm) Applicable pH RangeAcetate NaC2H3O2 500 2.09.0Tetraborate Na2B4O7 500 3.09.0Bromide NaBr 500 2.09.0Carbonate Na2CO3 500 3.09.0Chlorate KClO3 500 2.59.0Chloride NaCl
43、 1000 2.09.0Citrate H3C6H5O7 500 2.09.0Cyanide KCN 10 2.09.0Dichromate K2Cr2O7 20 2.59.0Fluoride NaF 500 4.09.0Iodide KI 500 2.09.0Nitrate KNO3 500 2.09.0Nitrite KNO2 500 2.59.0Oxalate (NH4)2C2O4 500 6.09.0Perchlorate KClO4 100 2.09.0Phosphate (NH4)2HPO4 20 2.09.0Pyrophosphate Na4P2O7 50 6.09.0Silic
44、ate Na2SiO3 100 2.04.5Sulfate (NH4)2SO4 500 2.09.0Sulfite Na2SO3 500 2.09.0Tartrate (NH4)2C4H9O6 500 3.09.0Thiocyanate KCNS 500 2.09.0Thiosulfate Na2S2O3 500 3.09.0E394 154where:A = absorbance, andT = percent transmittance.9.2.2 Evaluate the linearity of the calibration function by calculating the c
45、orrelation coefficient r. A typical proper value is r 60.9900.NOTE 3If the photometer readings are percent transmittance, they may be converted to absorbance as follows:A 5logS100T D (2)where:A = absorbance, andT = percent transmittance.NOTE 4If desired, the slope of the calibration line may be calc
46、ulated as follows:S 5L 3W (2)where:S = slope of calibration line, gFecm/absorbance unit,L = cell path length, cm, andW = micrograms of iron corresponding to an absorbance of 1.000 on the calibration line.10. Procedure10.1 Weigh to three significant figures a sample (pH less than 2) containing 1 to 1
47、00 g of iron into a 100-mL, glass-stopperedgraduated cylindervolumetric flask (Note 54). If the sample is water soluble, dissolve it in water and dilute to 80 mL with water.If the sample is not water soluble, methanol or another suitable solvent may be used (Note 65).NOTE 4The sample size should not
48、 exceed 80 mL. When using large samples, the miscibility of the samples and the reagents should be checkedbefore the determination is made. In any case, preliminary tests must be made to determine if the sample or any impurities in the sample interfere in anyway with the analysis. If a 1-cm cell is
49、used, the sample must contain at least 5 g of iron.NOTE 5Solvents that have been found suitable for use without recalibration include water, methanol, acetic acid, acetonitrile, and di- and triethyleneglycol. Acetone is not suitable. No solvents other than those listed have been tested.10.2 To prepare a reagent blank, add a quantity of water, approximately equal to the sample size in volume, to a secondgraduated cylinder.volumetric fla
