1、Designation: D 7441 08Standard Practice forSeparation of Beryllium from Other Metals in Digestion andExtraction Solutions from Workplace Dust Samples1This standard is issued under the fixed designation D 7441; the number immediately following the designation indicates the year oforiginal adoption or
2、, in the case of revision, the 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 practice covers the separation of beryllium fromother metals and metalloid
3、s in acid solutions, by extractionchromatography, for subsequent determination of beryllium byatomic spectroscopy techniques such as inductively coupledplasma atomic emission spectroscopy (ICP-AES).1.2 This practice is applicable to samples of settled dust thathave been collected in accordance with
4、Practices D 6966 orD 7296.1.3 This practice is compatible with a wide variety of aciddigestion techniques used in digesting settled dust samples,such as those described in Test Method D 7035.1.4 This practice is appropriate for the preparation of settleddust samples where an unacceptable bias is sus
5、pected or knownbecause of spectral interferences caused by other metals ormetalloids present in the sample. This practice may also beappropriate for the analysis of other types of samples.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is
6、theresponsibility of the user of this standard 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 1356 Terminology Relating to Sampling and An
7、alysis ofAtmospheresD 6966 Practice for Collection of Settled Dust SamplesUsing Wipe Sampling Methods for Subsequent Determi-nation of MetalsD 7035 Test Method for Determination of Metals and Met-alloids in Airborne Particulate Matter by InductivelyCoupled Plasma Atomic Emission Spectrometry (ICP-AE
8、S)D 7296 Practice for Collection of Settled Dust SamplesUsing Dry Wipe Sampling Methods for Subsequent De-termination of Beryllium and CompoundsE 882 Guide for Accountability and Quality Control in theChemical Analysis Laboratory3. Terminology3.1 For discussion of pertinent terms not discussed here,
9、 seeTerminology D 1356.3.2 Definitions:3.2.1 digestiondissolution using a combination of acidsand other reagents of solid materials into solution for subse-quent instrumental analysis.3.2.2 eluatethe effluent from a chromatography or resincolumn.3.2.3 extraction chromatographyliquid chromatographyap
10、plied to the separation of metal ions utilizing selectiveorganic extractants as the stationary phase and the aqueoussolution as the mobile phase (1)3.3.2.3.1 DiscussionExtraction chromatography resins con-sist of inert porous beads coated with selective extractants.3.2.4 spectral interferencean inte
11、rference caused by theemission from a species other than the analyte of interest.D 70353.2.5 surface wiperefers either to a wetted wipe, asdefined in Practice D 6966, or to a dry wipe, as defined inPractice D 7296, used to gather material from a surface forsubsequent analysis.3.2.5.1 DiscussionThe t
12、erms wipe sampling, swipe sam-pling, and smear sampling describe the techniques used toassess surface contamination on the skin, work surfaces, andPPE surfaces (for example, gloves, respirators, aprons, etc.)1This practice is under the jurisdiction of ASTM Committee D22 on Air Qualityand is the dire
13、ct responsibility of Subcommittee D22.04 on Workplace Air Quality.Current edition approved April 1, 2008. Published May 2008.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information,
14、refer to the standards Document Summary page onthe ASTM website.3The boldface numbers in parentheses refer to a list of references at the end ofthis standard.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.6 vacuum boxcontainer u
15、sed to maintain a vacuum ona resin or column sample in order to increase the rate of flowof liquid through the column. Other vacuum sources such as anaspirator may be used.4. Summary of Practice4.1 This practice is based on using extraction chromatogra-phy resin to separate beryllium ions from other
16、 metal ions inextracts and digestates of surface wipe samples.4.2 Surface wipe samples are collected using PracticeD 6966 or Practice D 7296, and are then digested or extractedinto solution by mineral acids.4.3 The pH of the solution is adjusted to between 1 and 2with sodium acetate.4.4 The sample i
17、s then loaded onto the extraction chroma-tography resin column, where beryllium is retained. Matrixinterferences are rinsed from the column with 0.2 M nitric acid.4.5 Beryllium is selectively eluted from the resin with 4 Mnitric acid and is available for analysis using the spectroscopictechniques su
18、ch as ICP-AES (See Test Method D 7035).5. Significance and Use5.1 Beryllium is an important analyte in industrial hygienebecause of the risk of exposed workers developing ChronicBeryllium Disease (CBD). CBD is a granulomatous lungdisease that is caused by the bodys immune system responseto inhaled d
19、ust or fumes containing beryllium, a humancarcinogen (2). Surface wipe samples and air filter samples arecollected to monitor the workplace. This practice addresses theproblem of spurious results caused by the presence of interfer-ing elements in the solution analyzed. The practice has beenevaluated
20、 for all elements having emission spectra near the313.042 and 313.107 nm beryllium lines, as well as elementsof general concern including aluminum, calcium, iron and lead.Below is a table listing each possible spectrally interferingelement:Cerium Chromium Hafnium MolybdenumNiobium Thorium Titanium T
21、huliumUranium Vanadium UraniumMeasurement of beryllium on the order of 1 ppb (0.003 gBe/100 cm2wipe sample) has been successfully accomplishedin the presence of spectrally interfering elements on the orderof hundreds of ppm. This method has been validated onmatrices containing 10 mg of each of the a
22、bove elements. Insome cases including interferents such as chromium andcalcium, the single 2 mL beryllium extraction chromatographyresin can handle 100 mg of total dissolved solids and stilldeliver 90 % beryllium yield. Should the matrix containgreater amounts of contaminants, additional resin may b
23、e usedor, more likely, a combination of different resins may be used.(3,4).6. Reagents and Materials6.1 Equipment:6.1.1 50-mL polypropylene centrifuge tubes,6.1.2 2-mL cartridges of beryllium extraction chromatogra-phy resin4,6.1.3 Syringe barrel (or similar size reservoir),6.1.4 Vacuum box, with fi
24、ttings compatible with the car-tridges,6.1.5 Delivery pipet, 5 mL or 10 mL,6.2 Reagents:(See Note 1.)6.2.1 Deionized Water, Type I or Type II in accordance withPractice D 1193,6.2.2 Nitric Acid (HNO3), concentrated, r1.42 g/mL(70 % m/m),6.2.3 Boric Acid (H3BO3),6.2.4 Ammonium Oxalate monohydrate (NH
25、4C2H4O),6.2.5 Sodium acetate trihydrate (C2H3O2Na3H2O),6.2.6 Methyl Violet (indicator grade).NOTE 1Purity of ReagentsReagent grade chemicals shall be used inall tests. Unless otherwise indicated, it is intended that all reagentsconform to the specifications of the Committee on Analytical Reagents of
26、the American Chemical Society where such specifications are available.Other grades may be used, provided it is first ascertained that the reagentis of sufficiently high purity to permit its use without lessening theaccuracy of the determination.6.3 Solutions:6.3.1 3.4 M Sodium acetate + 0.2 M Ammoni
27、um oxalate +(0.2 M Boric acid): To a l-L volumetric flask, add 500 mL ofdeionized water. Add 12.37 grams of Boric acid and mix untildissolved. Add 28.42 grams of Ammonium oxalate monohy-drate and mix until dissolved. Add 462.68 grams of Sodiumacetate trihydrate and mix. Fill to 1 L with deionized wa
28、ter andmix until dissolved.NOTE 2Boric acid is added to combat the effect of HF used indigestion. If HF is not used, the Boric acid may be omitted.6.3.2 Ammonium Oxalate, 0.25 M:To a l-L volumetric flask, add 500 mL of deionized water.Add 35.53 grams of Ammonium oxalate monohydrate and mixuntil diss
29、olved. Fill to 1 L with deionized water and mix untildissolved.6.3.3 Nitric Acid, 0.2 M:To a 1-L volumetric flask, add 200 mL of deionized water.Add 12.5 mL of concentrated (70%) nitric acid (trace metalgrade) and mix. Fill to 1 L with deionized water and mixthoroughly.6.3.4 Nitric Acid, 4.0 M:To a
30、1-L volumetric flask, add 200 mL of deionized water.Add 250 mL of concentrated (70 %) nitric acid (trace metalgrade) and mix. Fill to 1 L with deionized water and mixthoroughly.6.3.5 Methyl Violet, 0.1 % solution, in deionized water:0.1 gm Methyl Violet per 100 mL of water.7. Procedure7.1 Wipe Diges
31、t Preparation:4Beryllium extraction chromatography resin cartridge: 2 mL bed volume,50-100 micron beads, bis (2-ethylhexyl) methanediphosphonic acid sorbed ontoacrylic ester beads (3, 4, 5). Quality control parameters for the resin are stated insubsection 8.6.D74410827.1.1 Prepare resin load solutio
32、n in accordance with thechemical reagents normally used to digest beryllium surfacewipes.NOTE 3Example methods for sample preparation may be found inTest Method D 7035.7.1.2 Transfer extract from digested filter or wipe to a 50mL polypropylene centrifuge tube (see 6.1.1). The volumeshould be less th
33、an 20 mL at this point. If a larger volume isrequired to adequately digest the sample, check beryllium yieldwith a suitable matrix spike solution to verify acceptable yield,or consider increasing the amount of resin used. The digestedfilter solution may be slightly yellow, but should be free of anyf
34、ine solids. If the solution appears cloudy or if solids remainfollowing the digestion, filtration is required to remove fineparticulate matter which can impede the flow of solutionthrough the cartridge and may cause poor chromatographicperformance.7.1.3 Add 5-10 drops of 0.1 % methyl violet (see 6.3
35、.5). Forlarge numbers of samples, the methyl violet can be addeddirectly to the 3.4 M sodium acetate solution. For each 100 mLof 3.4 M sodium acetate prepared add 4 mL of 0.1 % methylviolet in deionized water or 4 mg of solid methyl violet (see6.2.6).7.1.4 Adjust the digested filter solution to a pH
36、 target of 1.5with 3.4 M sodium acetate + 0.2 M ammonium oxalate (+ 0.2M boric acid) (see 6.3.1). Upon the addition of methyl violet,the diluted digested filter solution should appear yellow.Addition of the sodium acetate solution will increase the pHand the solution will turn green (pH 0.5), blue-g
37、reen (pH 1),blue (pH 2) and dark violet (pH 2.5). The pH of the solutionshould be adjusted with the sodium acetate solution and 4 MHNO3until a blue-green or blue color is obtained. Anappropriate standard solution should be made for color com-parison.NOTE 4If HF is used in the digestion process, 0.2
38、M boric acid willbe needed to sequester any remaining fluoride ion. Without the boric acid,beryllium will form fluoride complexes which will not be retained by theberyllium extraction chromatography resin. The boric acid is added to thestock sodium acetate-ammonium oxalate solution.NOTE 5If hydrogen
39、 peroxide persists in the filter or wipe solutionfollowing digestion, the color of the pH indicator may fade, making itdifficult to monitor the pH effectively. If this happens, simply add 3-5drops of 0.1 % methyl violet indicator (see 6.3.5). For highly coloredsolutions, pH paper or a pH meter may b
40、e more effective for pHmeasurement than methyl violet.7.2 Beryllium Separation:7.2.1 Mount the 2 mL beryllium extraction chromatographyresin cartridge (see 6.1.2), equipped with a 20-30 mL reservoirto a vacuum source and container large enough to capture thecolumn effluent. Steps 7.2.27.2.4 may be c
41、ollected into thesame container (either a liner or 50-mL centrifuge tubes) anddiscarded as waste.7.2.2 Add the neutralized digested filter solution to thereservoir and pass the solution through the 2 mL berylliumextraction chromatography resin cartridge at 2 mL/min. Dis-card the eluate.7.2.3 Rinse t
42、he beryllium extraction chromatography resincartridge with 15 mL of 0.25 M ammonium oxalate (see 6.3.2)at 2 mL/min. Discard the eluate.7.2.4 Rinse the beryllium extraction chromatography resincartridge with 15 mL of 0.2 M HNO3(see 6.3.3) at 2 mL/min.Discard the eluate.7.2.5 Equip the vacuum box (see
43、 6.1.4) with a 50-mLpolypropylene centrifuge tube for each beryllium extractionchromatography resin cartridge.7.2.6 Elute the beryllium with 15 mL of 4.0 M HNO3(see6.3.4) at 1 mL/min. Collect the eluate in a 50-mL polypropy-lene centrifuge tube. A greater volume of 4 M nitric acid maybe used to incr
44、ease beryllium yield, but will result in a moredilute beryllium solution.7.2.7 Analyze the eluate for beryllium by ICP-AES inaccordance with Test Method D 7035.NOTE 6Other analysis methods may be suitable, for example, ICP-MS.8. Quality Control8.1 Laboratory BlanksCarry reagent blanks (water andreag
45、ents) and media blanks (unspiked filters) throughout theentire sample preparation and analytical process to determinewhether the samples are being contaminated from laboratoryactivities. Process reagent blanks at a frequency of at least 1per 20 samples, minimum of one per batch.8.2 Quality Control S
46、amples:8.2.1 Carry spiked filters and spiked duplicate filterthroughout the entire sample preparation and analytical processto estimate the method accuracy on the sample batch, ex-pressed as a percent recovery relative to the true spiked value.Spiked samples and spiked duplicate samples consist of f
47、iltersto which known amounts beryllium have been added. Processthese quality control samples in accordance with a frequency ofat least 1 per 20 samples, minimum of one per batch.8.2.2 Monitor the performance of the method by plottingcontrol charts of the relative percent recoveries and of therelativ
48、e percent difference between spiked samples and spikedduplicate samples. If quality control results indicate that themethod is out of control, investigate the reasons for this, takecorrective action, and repeat the analyses. See Guide E 882 forgeneral guidance on the use of control charts.8.3 Certif
49、ied Reference Materials (CRMs)If available,certified reference materials (CRMs) for beryllium shall beanalyzed prior to or during routine use of the sample prepara-tion and analytical method to establish whether the percentrecovery relative to the certified value is satisfactory.NOTE 7Typically, recoveries of 100 6 15 % are desired. However,for certain sample matrices, wider performance limits may be deemedacceptable.8.4 External Quality AssessmentIf the laboratory carriesout analysis of metals and metalloids in workplace air sampleson a regular basis, it is rec
