ASTM D4606-03(2007)
(Test Method)Standard Test Method for Determination of Arsenic and Selenium in Coal by the Hydride Generation/Atomic Absorption Method
Standard Test Method for Determination of Arsenic and Selenium in Coal by the Hydride Generation/Atomic Absorption Method
SIGNIFICANCE AND USE
This test method permits measurement of the total arsenic and selenium content of coal for the purpose of evaluating these elements where they can be of concern, for example, in coal combustion. When coal samples are prepared for analysis in accordance with this test method, the arsenic and selenium are quantitatively retained and are representative of the total amounts in the coal.
SCOPE
1.1 This test method covers the determination of total arsenic and selenium in coal.
1.2 &si-value;
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D4606 − 03(Reapproved 2007)
Standard Test Method for
Determination of Arsenic and Selenium in Coal by the
Hydride Generation/Atomic Absorption Method
This standard is issued under the fixed designation D4606; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope Sample of Coal and Coke by Instrumental Procedures
2 (Withdrawn 2010)
1.1 This test method covers the determination of total
arsenic and selenium in coal.
3. Summary of Test Method
1.2 The values stated in SI units are to be regarded as
3.1 Arsenic and selenium are determined by mixing a
standard. No other units of measurement are included in this
weighed coal sample with Eschka mixture and igniting at
standard.
750°C. The mixture is dissolved in hydrochloric acid and the
gaseous hydride of each element is generated from the appro-
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the priate oxidation state and determined by atomic absorption
spectrophotometry.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
4. Significance and Use
bility of regulatory limitations prior to use.
4.1 This test method permits measurement of the total
2. Referenced Documents
arsenic and selenium content of coal for the purpose of
evaluating these elements where they can be of concern, for
2.1 ASTM Standards:
example, in coal combustion.When coal samples are prepared
D121Terminology of Coal and Coke
for analysis in accordance with this test method, the arsenic
D346Practice for Collection and Preparation of Coke
and selenium are quantitatively retained and are representative
Samples for Laboratory Analysis
of the total amounts in the coal.
D2013Practice for Preparing Coal Samples for Analysis
D3173Test Method for Moisture in theAnalysis Sample of
5. Apparatus
Coal and Coke
5.1 Atomic Absorption Spectrophotometer,withbackground
D3180Practice for Calculating Coal and Coke Analyses
correction system and peak profile recording device.
from As-Determined to Different Bases
D5142Test Methods for ProximateAnalysis of theAnalysis 5.2 Hydride Generation Apparatus, for producing the hy-
drides of arsenic and selenium.
5.3 Burner or Heated Quartz Cell, for thermal decomposi-
This test method is under the jurisdiction of ASTM Committee D05 on Coal
tion of the hydrides.
and Coke and is the direct responsibility of Subcommittee D05.29 on Major
Elements in Ash and Trace Elements of Coal.
5.4 Hotplate, capable of maintaining a temperature of a
Current edition approved Oct. 1, 2007. Published October 2007. Originally
solution at 60 to 90°C.
approved in 1986. Last previous edition approved in 2003 as D4606–03. DOI:
10.1520/D4606-03R07.
5.5 Ignition Crucibles—Porcelain crucible of 30-mLcapac-
For information concerning experimental work on which this test method is
ity. Do not use porcelain crucible in which the glaze is flaked.
based see: Bosshart, R. E., Price, A. A., and Ford, C. T., “Evaluation of the Effect
of Coal Cleaning on Fugitive Elements, Phase II Final Report, Part II Analytical
5.6 Analytical Balance, capable of weighing to 0.0001 g.
Methods,” ERDA Report No. C00-44727-35 , 1980, pp. 94–102; Fernandez, F. J.,
“Atomic Absorption Determination of Gaseous Hydrides Utilizing Sodium Boro-
6. Reagents
hydrideReduction,” Atomic Absorption Newsletter,Vol12,No.4,1973,pp.93–97;
and Brodie, K. G., “AComparative Study—DeterminingArsenic and Selenium by 6.1 Purity of Reagents—Reagent grade chemicals shall be
AAS,” American Laboratory , March 1977, pp. 73–78.
used in all tests. Unless otherwise indicated, it is intended that
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
The last approved version of this historical standard is referenced on
the ASTM website.
www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4606 − 03 (2007)
all reagents shall conform to the specifications of the Commit- 8. Sample Preparation and Solution
tee onAnalytical Reagents of theAmerican Chemical Society,
8.1 To minimize the potential for contamination, clean all
where such specifications are available.
labware thoroughly with dilute HCl solution (1+9) and rinse
6.2 Purity of Water—Use high-purity, conductivity water, with deionized water. The hydride generation apparatus shall
prepared by passing distilled water (or equivalent) through an
be kept equally clean.
ion exchange resin.
8.2 Weigh approximately1gof coal into a preweighed
6.3 Eschka Mixture—Thoroughly mix two parts by weight
30-mL crucible. Record the weight to the nearest 0.0001 g.
of light calcined magnesium oxide (MgO) with one part by
Thoroughly mix the sample with 1.5 g of Eschka mixture and
weight anhydrous sodium carbonate (Na CO ). The mixture
cover the mixture with an additional 1.5 g of Eschka mixture.
2 3
shall be as free as possible from arsenic and selenium.
Place the sample in a cold muffle furnace. Set the temperature
controlto500°C.Heatthesamplefor1h.Increasethefurnace
6.4 Hydrochloric Acid Concentrated (sp gr 1.19)—
temperature to 750°C. Continue heating at this temperature for
Concentrated hydrochloric acid (HCl).
3h.Removethesampleandallowtocooltoroomtemperature.
6.5 Hydrochloric Acid (1+4) —Mix one volume of con-
8.3 Add 20 to 30 mL of hot deionized water to a 150-mL
centrated hydrochloric acid (HCl, sp gr 1.19) with four
beaker. Transfer the contents of the crucible from 8.2 to the
volumes of deionized water.
beaker. Add 5 mL of concentrated HCl to the crucible. Then
6.6 Potassium Iodide Solution 20% (weight per volume)—
slowly and carefully, with the aid of a stirring rod, transfer the
Dissolve20gofpotassiumiodide(KI)in100mLofdeionized
HCltothebeaker.Rinseanyremainingmaterialinthecrucible
water.
into the beaker with deionized water.Add 15-mLconcentrated
6.7 Sodium Borohydride (Pellets or Solution) 3% (weight
HCl in three 5-mL portions to the crucible and transfer to the
pervolume)—Toa1%(weightpervolume)sodiumhydroxide
beaker.SwirlthecontentsuntiltheEschkahasdissolved(Note
(NaOH) solution, add sodium borohydride (NaBH ) to give a
1).Coolthesolutionandtransferittoa100-mLpolypropylene
solution 3 % (weight per volume) sodium borohydride
volumetric flask. Dilute to volume with deionized water.
(NaBH ). Prepare fresh daily.
NOTE 1—Some residue can remain.
6.8 Arsenic Stock Solution (1000-ppm Arsenic)—Certified
commercially available standard solution or prepared from
9. Blank
primary standard arsenic trioxide (As O ).
2 3
9.1 Weigh 15 g of Eschka mixture into a crucible. Heat as
6.9 Selenium Stock Solution (1000-ppm Selenium)—
described in 8.2.Add 100- to 150-mLhot deionized water to a
Certified commercially available standard solution or prepared
500-mL beaker. Transfer the contents of the crucible to the
from selenium metal (99.99%).
beaker. Add 25-mL concentrated HCl to the crucible. Then
slowly and carefully, with the aid of a stirring rod, transfer the
7. Analysis Sample
HCltothebeaker.Rinseanyremainingmaterialinthecrucible
7.1 Obtain the sample for coal in accordance with Method into the beaker with deionized water.Add 75-mLconcentrated
HCl in three 25-mLportions to the crucible and transfer to the
D2013 and the sample for coke in accordance with Practice
beaker.SwirlthecontentsuntiltheEschkahasdissolved(Note
D346. Prepare the analysis sample by pulverizing the material
1). Cool the solution and transfer to a 500-mL polypropylene
to pass a 250-µm (No. 60) U.S. standard sieve.
volumetric flask. Dilute to volume with deionized water.
7.2 A separate portion of the analysis sample shall be
analyzed concurrently for moisture content in accordance with
10. Procedure for Arsenic
Test Method D3173 or Test Methods D5142.
10.1 The solutions and preparations described are typical
7.3 Use certified reference materials, such as the National
for North American coals. Different solution concentrations
Institute of Standards and Technology (NIST) Standard Refer-
can be required to establish suitable analytical results for those
ence Material (SRM) coals. SRM 1632b and SRM 1635 are
elements with concentrations outside the typical range. Each
two different coal samples which are currently available and
analyst shall determine the sensitivity and optimum method of
have certified values for both arsenic and selenium. Results
calibration of their own equipment and choose standards with
obtained by analyzing these coals for arsenic and selenium
concentration ranges compatible with the samples and instru-
using the test methods described herein can be used for
ments specific to their work. Twenty millilitres is a normal
checking analytical technique and test method accuracy. At
working volume for batch hydride generation systems. If a
least one SRM coal sample should be analyzed as a control
hydride generation system is designed to accommodate other
when a set of coal samples are analyzed.
than20mL(sample+acid),adifferentvolumecanbeusedand
all reagents and sample volumes can be ratioed accordingly.
10.2 Prepareanintermediatearsenicstandard1to10µg/mL
Reagent Chemicals, American Chemical Society Specifications , American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
from the stock solution. Prepare fresh daily. Prepare a working
listed by the American Chemical Society, see Analar Standards for Laboratory
standard (Note 2) by adding 1 mLof the intermediate standard
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
to a 100-mLpolypropylene volumetric flask. Dilute to volume
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
MD. with blank (Section 9).
D4606 − 03 (2007)
NOTE 2—Five millilitres of the working standard should produce a
reaction flasks so that the final volume of solution in the
signal approximately in the middle of the linear dynamic range for the
reaction flask is 20 mL.
atomic absorption operating conditions chosen.
11.5 Use a selenium hollow cathode or electrodeless dis-
10.3 Prepare three calibration standards by combining vol-
charge lamp and set the monochromator for 196.0 nm.Adjust
umes of the working standard and blank solution which yield
instrumentparameterstooptimumfortheparticula
...
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