ASTM D4085-1993(2003) Standard Test Method for Metals in Cellulose by Atomic Absorption Spectrophotometry《原子吸收分光光度计对纤维素中金属的试验方法》.pdf

1、Designation: D 4085 93 (Reapproved 2003)Standard Test Method forMetals in Cellulose by Atomic AbsorptionSpectrophotometry1This standard is issued under the fixed designation D 4085; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, t

2、he year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the iron,copper, manganese, and calcium content of cellulose

3、pulp fromwood or cotton.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prio

4、r to use.2. Referenced Documents2.1 ASTM Standards:D 1193 Specification for Reagent Water2D 1348 Test Methods for Moisture in Cellulose3D 3516 Test Methods for Ashing Cellulose3E 177 Practice for Use of the Terms Precision and Bias inASTM Test Methods4E 691 Practice for Conducting an Interlaboratory

5、 Study toDetermine the Precision of a Test Method43. Summary of Test Method3.1 The sample is ashed in accordance with Test MethodsD 3516.3.2 This test method is dependent on the fact that metallicelements in the ground state will absorb light of the samewavelength they emit when excited. When radiat

6、ion from agiven excited element is passed through a flame containingground-state atoms of that element, the intensity of the trans-mitted radiation will decrease in proportion to the amount ofthe ground-state element in the flame. A hollow cathode lampwhose cathode is made of the element to be deter

7、minedprovides the radiation. The metal atoms to be measured areplaced in the beam of radiation by aspirating the specimen intoan oxidant-fuel flame. A monochromator isolates the charac-teristic radiation from the hollow cathode lamp and a photo-sensitive device measures the attenuated transmitted ra

8、diation.4. Significance and Use4.1 Manganese in pulp acts as a catalyst in oxidizingcellulose.4.2 Iron in pulp can cause yellowness in rayon fibers andinfluence cellulose acetate plastics color. Iron also causesproblems in photographic and blueprint papers.4.3 Copper in pulp can act as a retardant i

9、n oxidizingcellulose and can affect viscose ripening. Copper interfereswith the dye level of rayon fibers and influences celluloseacetate plastics color.4.4 Calcium in pulps can cause problems in processing intoacetate, rayon, cellophane, etc. Calcium can create undesirabledeposits in viscose spinni

10、ng and film casting operation. Cal-cium can influence viscosity control during cellulose acetatemanufacture.5. Apparatus5.1 Atomic Absorption Spectrophotometer, consisting of anatomizer and burner, suitable pressure-regulating devices ca-pable of maintaining constant oxidant and fuel pressure for th

11、eduration of the test, a hollow cathode lamp for each metal to betested, an optical system capable of isolating the desired line ofradiation, an adjustable slit, a photomultiplier tube or otherphotosensitive device, and a read-out mechanism for indicatingthe amount of absorbed radiation.5.2 OxidantA

12、ir, which has been cleaned and driedthrough a suitable filter to remove oil, water, and other foreignsubstances, is the usual oxidant.5.3 FuelAcetylene, commercially available, is the usualfuel. Acetone, always present in acetylene cylinders, can beprevented from entering and damaging the burner hea

13、d byreplacing a cylinder that has a gage pressure of only 3.5 kPa(50 psi) remaining.5.4 Volumetric Flasks, 25, 100, and 1000-mL.NOTE 1In listing the apparatus for this method, the items required for1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materi

14、als, and Applications and is the direct responsibility ofSubcommittee D01.36 on Cellulose and Cellulose Derivatives.Current edition approved May 10, 2003. Published June 2003. Originallyapproved in 1981. Last previous edition approved in 1993 as D 4085 93 (1997).2Annual Book of ASTM Standards, Vol 1

15、1.01.3Annual Book of ASTM Standards, Vol 06.03.4Annual Book of ASTM Standards, Vol 14.02.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.the ashing step are not listed. For these items refer to Test MethodsD 3516.6. Reagents6.1 Purit

16、y of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.6.2 Purity of WaterUnless

17、otherwise indicated, referencesto water should be understood to mean reagent water conform-ing to the requirements in Specification D 1193, Type I.6.3 Hydrochloric Acid (1 + 1)Add 50 mL of concentratedhydrochloric acid (HCl, sp gr 1.19) to 50 mL of water.6.4 Hydrochloric Acid (1 + 99)Dilute 10 mL of

18、 concen-trated hydrochloric acid (HCl, sp gr 1.19) to 1000 mL withwater.6.5 Nitric Acid (1 + 1)Add 50 mL of concentrated nitricacid (HNO3, sp gr 1.42) to 50 mL of water.6.6 Sulfuric Acid (1 + 1)Add 50 mL of concentratedsulfuric acid (H2SO4, sp gr 1.84) to 50 mL of water.6.7 Standard SolutionsDilute

19、the solutions that followwith HCl (1 + 99) to prepare the standards to be used forcalibration. Store all solutions in polyethylene bottles.6.7.1 Iron (1 mL = 1.0 mg Fe)Dissolve 1.000 g of pureiron in 100 mL of H2SO4(1 + 1) with the aid of heat. Cool anddilute to 1 L.6.7.2 Copper (1 mL = 1.0 mg Cu)Di

20、ssolve 1.000 g ofelectrolytic copper contained in a 250-mL beaker in 30 mL ofnitric acid (1 + 1). Slowly add 4 mL of H2SO4(1 + 1) and heatuntil SO3fumes evolve. Cool and dilute to 1 L.6.7.3 Manganese (1 mL = 1.0 mg Mn)Dissolve 3.076 gof manganous sulfate monohydrate (MnSO4H2O) in a mixtureof 10 mL o

21、f HCl and 100 mL of water. Dilute to 1 L.6.7.4 Calcium (1 mL = 1.0 mg Ca)Weigh 2.497 g ofcalcium carbonate (CaCO3) and transfer it to a 500-mLErlenmeyer flask. Add 10 mL of water. Pour 10 mL of HClslowly down the side of the flask. Add an additional 200 mL ofwater and heat until solution is complete

22、. Cool and dilute to 1L.NOTE 2Acceptable standard solutions are available commerciallyfrom any laboratory supply house.6.8 Lanthanum Solution (50 g/L)Wet 58.65 g of lantha-num oxide (La2O3) with water. Add slowly 250 mL of HCl tothe mixture. When dissolved dilute to 1 L with water.7. Preparation of

23、the Sample7.1 Select a representative sample in the amount of 30 g, 5g for the determination of moisture and 25 g for the determi-nation of the metals.8. Procedure8.1 Weigh about 25 g of pulp to the nearest 0.01 g. At thesame time weigh out a separate sample for oven-dry cellulosedetermination. Ash

24、the sample by Method D in Test MethodsD 3516. Determine moisture content in accordance with TestMethods D 1348.NOTE 3Method D in Test Methods D 3516 has been listed as thepreferred one because it minimizes opportunity for sample loss duringashing, especially for the iron determination. However for c

25、alcium, ormanganese greater than 1 mg/kg, low results may occur from sulfateinterferences and Method A in Test Methods D 3516 may be preferred.8.2 Calibration and Standardization of Atomic AbsorptionSpectrophotometer:8.2.1 The method of operation varies with different modelsof atomic absorption spec

26、trophotometers. Therefore, no at-tempt is made here to describe in detail the steps for placing aninstrument into operation.8.2.2 Prepare working standard solutions daily from thosedescribed in 6.7. Make the final calcium dilutions to contain1 % lanthanum.8.2.3 Atomize the standards and calibrate th

27、e spectropho-tometer for the element of interest.8.3 Analyze the sample solutions prepared from 24.13 and24.14 of Method D in Test Methods D 3516 in accordance with8.2. Iron, copper, and manganese normally can be run withoutfurther dilutions. Dilutions for calcium should be made 1 % inlanthanum.NOTE

28、 4If Method A in Test Methods D 3516 was used, digest the ashfrom 7.4 with 5 mL HCl (1 + 1) on a steam bath, cool and dilute in a25-mL volumetric flask to volume with water. Further dilutions forcalcium should be made 1 % in lanthanum.8.3.1 A reagent blank should be used to zero the atomicabsorption

29、 spectrophotometer before taking sample readings.9. Calculations9.1 Calculate the concentration of the metallic ion, inmilligrams per litre, using the calibration determined in 8.2.3.M 5C 3 VW(1)where:M = metal content, mg/kg,C = amount of material determined in sample solution,mg/L,V = final diluti

30、on volume of sample, mL, andW = weight of oven-dry cellulose, g.10. Precision and Bias10.1 PrecisionAn interlaboratory study of this procedurewas conducted in accordance with Practice E 691. Four labo-ratories conducted tests on a single cellulose pulp using bothdry ashing and wet ashing procedures.

31、 A fifth laboratory usedonly wet ashing. At the 95 % confidence level, results shouldagree within the limits shown in new Table 1 and Table 2.Since all sources of error in this procedure are not likelyproportional to the test level, these precision statements maynot apply at levels far removed from

32、those in the tables.TABLE 1 Dry AshingMetalTypical Value,mg/kg95 % Confidence,mg/kgIron 4.0 62.4Copper 0.22 60.35Manganese 2.0 61.0Calcium 201 659D 4085 93 (2003)210.2 BiasIn the absence of a suitable reference material,no accuracy determination is possible. It should be noted,however, that dry ashi

33、ng methods are subject to loss of somemetals during ignition, yielding lower results than wet ashingprocedures. This may have been the case for the iron andcopper results in the interlaboratory test.11. Keywords11.1 analysis; atomic absorption; cellulose; metalsASTM International takes no position r

34、especting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.Thi

35、s standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM Inte

36、rnational Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown

37、below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).TABLE 2 Wet AshingMetalTypical Value,mg/kg95 % Confidence,mg/kgIron 5.9 64.1Copper 0.91 61.43Manganese 1.9 61.0Calcium 193 632D 4085 93 (2003)3