ASTM D4085-1993(2008) 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标准试验方法》.pdf

1、Designation: D 4085 93 (Reapproved 2008)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 () 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 p

3、ulp fromwood or cotton.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 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 sta

4、ndard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 1193 Specification for Reagent WaterD 1348 Test Methods for Moisture in CelluloseD 3516 Test Methods for Ashing CelluloseE

5、177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Summary of Test Method3.1 The sample is ashed in accordance with Test MethodsD 3516.3.2 This test method is dependent on the fac

6、t that metallicelements in the ground state will absorb light of the samewavelength they emit when excited. When radiation 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 th

7、e amount ofthe ground-state element in the flame. A hollow cathode lampwhose cathode is made of the element to be determinedprovides 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 cha

8、rac-teristic radiation from the hollow cathode lamp and a photo-sensitive device measures the attenuated transmitted radiation.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 pl

9、astics color. Iron also causesproblems in photographic and blueprint papers.4.3 Copper in pulp can act as a retardant in 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 cau

10、se problems in processing intoacetate, rayon, cellophane, etc. Calcium can create undesirabledeposits in viscose spinning and film casting operation. Cal-cium can influence viscosity control during cellulose acetatemanufacture.5. Apparatus5.1 Atomic Absorption Spectrophotometer, consisting of anatom

11、izer and burner, suitable pressure-regulating devices ca-pable of maintaining constant oxidant and fuel pressure for theduration 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 t

12、ube or otherphotosensitive device, and a read-out mechanism for indicatingthe amount of absorbed radiation.5.2 OxidantAir, 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 t

13、he usualfuel. Acetone, always present in acetylene cylinders, can beprevented from entering and damaging the burner head byreplacing a cylinder that has a gage pressure of only 3.5 kPa(50 psi) remaining.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, M

14、aterials, and Applications and is the direct responsibility ofSubcommittee D01.36 on Cellulose and Cellulose Derivatives.Current edition approved June 1, 2008. Published June 2008. Originallyapproved in 1981. Last previous edition approved in 2003 as D 4085 93 (2003).2For referenced ASTM standards,

15、visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 1942

16、8-2959, United States.5.4 Volumetric Flasks, 25, 100, and 1000-mL.NOTE 1In listing the apparatus for this method, the items required forthe ashing step are not listed. For these items refer to Test MethodsD 3516.6. Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unle

17、ss 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 otherwise indicated, referencesto water should be understood to mean

18、 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 concen-trated hydrochloric acid (HCl, sp gr 1.19) to 1000 mL withwa

19、ter.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 the solutions that followwith HCl (1 + 99) to prepare the standards

20、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)Dissolve 1.000 g ofelectrolytic copper contained in a 250-mL beaker in

21、 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 g ofmanganous sulfate monohydrate (MnSO4H2O) in a mixture of10 mL of HCl and 100 mL of water. Dilute to 1 L.6.7.4 Calcium (1 mL = 1.0 m

22、g 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. Cool and dilute to 1L.NOTE 2Acceptable standard solutions are avai

23、lable 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 the Sample7.1 Select a representative sample in the amount of 30 g,

24、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 the sample by Method D in Test MethodsD 3516. Determine moisture con

25、tent 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 calcium, ormanganese greater than 1 mg/kg, low results may occur from

26、 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 spectrophotometers. Therefore, no at-tempt is made here to describe in d

27、etail 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 the spectropho-tometer for the element of interest.8.3 Analyze the sam

28、ple 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 4If Method A in Test Methods D 3516 was used, digest the ashfrom 7.

29、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 spectrophotometer before taking sample readings.9. Calculations9.1

30、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 dilution volume of sample, mL, andW = weight of oven-dry cellulose, g.10.

31、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. A fifth laboratory usedonly wet ashing. At the 95 % confidence leve

32、l, 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 those in the tables.10.2 BiasIn the absence of a suitable reference

33、material,no accuracy determination is possible. It should be noted,however, that dry ashing methods are subject to loss of somemetals during ignition, yielding lower results than wet ashingD 4085 93 (2008)2procedures. This may have been the case for the iron andcopper results in the interlaboratory

34、test.11. Keywords11.1 analysis; atomic absorption; cellulose; metalsASTM International takes no position respecting 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

35、 such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This 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 in

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37、d a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown 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 t

38、his 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 1 Dry AshingMetalTypical Value,mg/kg95 % Confidence,mg/kgIron 4.0 62.4Copper 0.22 60.35Manganese 2.0 61.0Calcium 201 659TABLE 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 (2008)3