ASTM D8027-17

Standard Practice for Concentration of Select Radionuclides Using MnO<inf>2</inf > for Measurement Purposes

SIGNIFICANCE AND USE
5.1 This practice is applicable to the separation of specific radionuclides of interest as part of overall radiochemical analytical methods. Radionuclides of interest may need to be quantified at activity levels of less than 1 Bq. This may require measurement of less than 1 fg of analyte in a sample which has a mass of a gram to more than several kilograms. This requires concentration of radionuclides into a smaller volume counting geometry or exclusion of species which would impede subsequent chemical separations, or both. MnO2 has shown good selectivity in being able to concentrate the following elements: actinium (Ac), bismuth (Bi), lead (Pb), polonium (Po), plutonium (Pu), radium (Ra), thorium (Th), and uranium (U) as noted in the referenced literature (see Sections 4 and 8). The MnO2 can be loaded onto a variety of substrates in preparation for use or generated in-situ in an aqueous solution. The presented processes are not meant to be all encompassing of what is possible or meant to address all limitations of using MnO2. Some limitations are noted in Section 6, Interferences.
SCOPE
1.1 This practice is intended to provide a variety of approaches in which manganese oxide (MnO2) can be used to concentrate radionuclides of interest into a smaller volume counting geometry or exclude other species that would otherwise impede subsequent chemical separation steps in an overall radiochemical method, or both.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 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.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-May-2017
• ICS: 17.240 - Radiation measurements
• Technical Committee: D19 - Water
• Drafting Committee: D19.04 - Methods of Radiochemical Analysis

Relations

• Replaces: ASTM D8027-16 - Standard Practice for Concentration of Select Radionuclides Using MnO<inf>2</inf > for Measurement Purposes
• Effective Date: 01-Jun-2017
• Refers: ASTM D7902-20 - Standard Terminology for Radiochemical Analyses
• Effective Date: 01-May-2020
• Refers: ASTM D1129-13(2020)e2 - Standard Terminology Relating to Water
• Effective Date: 01-May-2020
• Refers: ASTM D7902-18 - Standard Terminology for Radiochemical Analyses
• Effective Date: 01-Feb-2018
• Refers: ASTM D7902-16 - Standard Terminology for Radiochemical Analyses
• Effective Date: 01-Feb-2016
• Refers: ASTM D7902-14 - Standard Terminology for Radiochemical Analyses
• Effective Date: 15-Jan-2014
• Refers: ASTM D7902-14e1 - Standard Terminology for Radiochemical Analyses
• Effective Date: 15-Jan-2014
• Refers: ASTM D1129-10 - Standard Terminology Relating to Water
• Effective Date: 01-Mar-2010
• Refers: ASTM D1129-06ae1 - Standard Terminology Relating to Water
• Effective Date: 01-Sep-2006
• Refers: ASTM D1129-06a - Standard Terminology Relating to Water
• Effective Date: 01-Sep-2006
• Refers: ASTM D1129-06 - Standard Terminology Relating to Water
• Effective Date: 15-Feb-2006
• Refers: ASTM D1129-04 - Standard Terminology Relating to Water
• Effective Date: 01-Mar-2004
• Refers: ASTM D1129-04e1 - Standard Terminology Relating to Water
• Effective Date: 01-Mar-2004
• Refers: ASTM D1129-03a - Standard Terminology Relating to Water
• Effective Date: 10-Aug-2003
• Refers: ASTM D1129-03 - Standard Terminology Relating to Water
• Effective Date: 10-Mar-2003

Overview

ASTM D8027-17: Standard Practice for Concentration of Select Radionuclides Using MnO₂ for Measurement Purposes is an internationally recognized standard published by ASTM International. This practice outlines approaches for using manganese dioxide (MnO₂) to concentrate specific radionuclides-such as actinium, bismuth, lead, polonium, plutonium, radium, thorium, and uranium-for radiochemical analysis. Concentration is essential when the target radionuclides are present at low activity levels (often below 1 becquerel) or extremely small mass, necessitating precise quantification in environmental and laboratory samples.

MnO₂ provides favorable selectivity, allowing efficient concentration of these elements in preparation for analytical measurement while also excluding other species that could interfere with chemical separation processes. MnO₂ can be applied on various substrates or generated in-situ within aqueous matrices, making it adaptable to a range of radiochemical methodologies and sample types.

Key Topics

• Radionuclide Concentration: MnO₂ acts as a selective sorbent for certain radionuclides, enabling their pre-concentration from large samples into a reduced volume suited for measurement.
• Versatile Preparation Methods: The standard describes multiple established techniques to synthesize hydrous MnO₂, including oxidation, reduction, and use of commercial or laboratory reagents.
• Sample and Substrate Versatility: MnO₂ can be utilized as a precipitate, loaded onto resins, polymer fibers, cartridges, or thin films for efficient extraction and analysis.
• Interference Management: Instructions are given for addressing matrix effects, including high concentrations of divalent cations and naturally occurring isotopes in reagents, which can impact analyte recovery.
• Sensitivity: This practice supports the detection and quantification of radionuclides present at extremely low concentrations, suitable for both environmental and process monitoring scenarios.
• Safety and Compliance: Users are responsible for establishing safety, health, and regulatory protocols, in accordance with international standards principles recognized by the WTO TBT Committee.

Applications

This ASTM standard offers practical value across diverse sectors where radiochemical analysis at ultra-trace levels is required:

• Environmental Monitoring: Used for groundwater, surface water, and seawater sampling to identify and quantify radionuclides as part of environmental health assessments and regulatory compliance.
• Nuclear Industry: Supports radiochemical monitoring in nuclear facilities, waste management, decommissioning processes, and fuel cycle operations.
• Geochemical Research: Enables tracing and studies of natural radionuclide migration, sediment analysis, and hydrological cycle investigations by concentrating and measuring isotopes like radium and uranium.
• Water Quality Assessment: Facilitates testing for radionuclide contamination in drinking water and wastewater, often required for public health protection.
• Analytical Laboratories: Standardizes procedures for sample pre-treatment and concentration prior to instrumental analysis (e.g., alpha spectrometry, gamma spectrometry), ensuring comparability and reliability of results.

Related Standards

For comprehensive radiochemical analysis and water testing, the following ASTM standards and referenced documents supplement ASTM D8027-17:

• ASTM D1129 - Terminology Relating to Water
• ASTM D7902 - Terminology for Radiochemical Analyses

ASTM D8027-17 aligns with international best practices and contributes to the reliability and reproducibility of radionuclide measurements in scientific and regulatory contexts.

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Keywords: ASTM D8027-17, manganese dioxide, MnO₂, radionuclide concentration, radiochemical analysis, water testing, environmental monitoring, nuclear industry, standard practice, hydrous manganese oxide, pre-concentration.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D8027 − 17
Standard Practice for
Concentration of Select Radionuclides Using MnO for
Measurement Purposes
This standard is issued under the fixed designation D8027; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 4. Summary of Practice
1.1 This practice is intended to provide a variety of ap- 4.1 These practices describe different processes through
proaches in which manganese oxide (MnO ) can be used to which MnO can be used to concentrate specific radionuclides
2 2
concentrate radionuclides of interest into a smaller volume of interest into a smaller volume counting geometry or exclude
counting geometry or exclude other species that would other- other species that would otherwise impede subsequent chemi-
wiseimpedesubsequentchemicalseparationstepsinanoverall cal separation steps in an overall radiochemical method, or
radiochemical method, or both. both.
1.2 The values stated in SI units are to be regarded as 4.2 Published studies (1-5) have addressed in detail the
standard. No other units of measurement are included in this various manners in which hydrous manganese dioxides can be
standard. synthesized and the variety of crystal forms of hydrous
manganese dioxide that can result. The literature describes the
1.3 This standard does not purport to address all of the
following general categories in which hydrous manganese
safety concerns, if any, associated with its use. It is the
dioxide can be prepared.
responsibility of the user of this standard to establish appro-
4.2.1 Guyard Reaction:
priate safety and health practices and determine the applica-
21 1
bility of regulatory limitations prior to use. 3Mn 12MnO 12H O→5MnO 14H
4 2 2
1.4 This international standard was developed in accor-
4.2.2 By the reduction of permanganate with reducing
dance with internationally recognized principles on standard-
reagents such as hydrogen peroxide (H O ) or hydrogen
2 2
ization established in the Decision on Principles for the
chloride (HCl).
Development of International Standards, Guides and Recom-
4.2.3 By the oxidation of Mn(II) salt under alkaline condi-
mendations issued by the World Trade Organization Technical
tions with oxidizing reagents such as potassium chlorate
Barriers to Trade (TBT) Committee.
(KClO ), H O , ozone (O ), or ammonium persulfate
3 2 2 3
((NH ) S O ).
4 2 2 8
2. Referenced Documents
4.3 The presented practices are not meant to address every
2.1 ASTM Standards:
possible approach to the generation and use of MnO but are
D1129 Terminology Relating to Water
meant to present some more typical practices that may be
D7902 Terminology for Radiochemical Analyses
generally useful.
3. Terminology
5. Significance and Use
3.1 Definitions:
5.1 This practice is applicable to the separation of specific
3.1.1 For definitions of terms used in this standard, refer to
radionuclides of interest as part of overall radiochemical
Terminologies D1129 and D7902.
analytical methods. Radionuclides of interest may need to be
quantified at activity levels of less than 1 Bq. This may require
measurement of less than 1 fg of analyte in a sample which has
This practice is under the jurisdiction of ASTM Committee D19 on Water and
a mass of a gram to more than several kilograms.This requires
is the direct responsibility of Subcommittee D19.04 on Methods of Radiochemical
concentration of radionuclides into a smaller volume counting
Analysis.
geometry or exclusion of species which would impede subse-
Current edition approved June 1, 2017. Published June 2017. Originally
approved in 2016. Last previous edition approved in 2016 as D8027 – 16. DOI:
quent chemical separations, or both. MnO has shown good
10.1520/D8027-17.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on The boldface numbers in parentheses refer to a list of references at the end of
the ASTM website. this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D8027 − 17
selectivity in being able to concentrate the following elements: 7.5 Hydrogen peroxide, 30 % H O —TheACSspecification
2 2
actinium (Ac), bismuth (Bi), lead (Pb), polonium (Po), pluto- allows for a concentration range of 29 to 32 %.
nium (Pu), radium (Ra), thorium (Th), and uranium (U) as
7.6 Iron chloride, FeCl .
noted in the referenced literature (see Sections 4 and 8). The
7.7 Potassium permanganate, KMnO .
MnO can be loaded onto a variety of substrates in preparation
for use or generated in-situ in an aqueous solution. The 7.8 Potassium permanganate, 0.5 M KMnO —Add 79 g of
presented processes are not meant to be all encompassing of
KMnO to 750 mL water. Dilute to 1 L with water and mix
what is possible or meant to address all limitations of using well.
MnO . Some limitations are noted in Section 6, Interferences.
7.9 Sodium hydroxide, 0.01 M NaOH—Add 0.1 g NaOH to
250 mL water.
6. Interferences
7.10 PhenolphthaleinpHindicatorsolution—Commercially
6.1 MnO is able to achieve a very good decontamination
available as 1 % solution in ethanol.
factor from monovalent cations in solution as evidenced by 8.5
below in which it is used in seawater. However, in the case of
7.11 Sodium hydroxide, 10 M—Carefully dissolve 400 g of
elevated concentrations of divalent cations, for example
NaOH in about 900 mL of water and dilute to 1 L.
barium, the recovery of analytes of interest can be significantly
7.12 Manganese (II) chloride, 0.5 M—Dissolve 11.7 g of
reduced (6).Additionally in the case of seawater, the recovery
MnCl2•6H2O in about 80 mL of water and dilute to 100 mL.
of analytes such as uranium may also be substantially reduced.
Insuchcasestheuseofanisotopictracercanbeveryimportant
8. Procedure
to correct for such reduced recovery. The MnO separation is
8.1 Use of MnO Generated in-situ to Pre-Concentrate
also very conducive to being easily repeated to achieve a
Sample Analytes:
second stage of separation from potentially interfering species.
8.1.1 The precipitation of MnO from a water sample may
7. Reagents be most conveniently performed on a volume of 0.1 to 2 L but
larger volumes are possible (7 and 8). Any isotopic tracers
7.1 Purity of Reagents—Reagent grade chemicals shall be
should be added and the valence states of the tracers and
used in all tests. Unless otherwise indicated, it is intended that
analyte species allowed to equilibrate before proceeding.
all reagents shall conform to the specifications of the Commit-
8.1.2 Add to the water sample approximately 10 mg of
tee onAnalytical Reagents of theAmerican Chemical Society,
4 KMnO and allow to dissolve. Optionally, approximately 2 mg
where such specifications are available. Other grades may be
of FeCl may also be added to improve the obtainable
used, provided that the reagent is of sufficiently high purity to
separation factor.
permit its use without increasing the background of the
8.1.3 The pH indicator bromocresol purple may be added to
measurement.
the water sample to provide a color indicator in the following
7.1.1 Some reagents, even those of high purity, may contain
step of raising the pH.
naturally occurring radioactivity, such as isotopes of uranium,
8.1.4 Add to the water sample approximately 1 mLof about
radium, actinium, thorium, rare earths and potassium com-
30%H O .
2 2
pounds or artificially produced radionuclides, or both.
8.1.5 The precipitation step to follow is best performed at
Consequently, when such reagents are used in the analysis of
ambient temperature if a period of one or more days is
low-radioactivity samples, the activity of the reagents shall be
available to allow for complete settling and development of the
determined under analytical conditions that are identical to
precipitate. Alternatively the promptness of the precipitation
those used for the sample. The activity contributed by the
canbeassistedbygentlyheatingthewatersample,forexample
reagents may be considered to be a component of background
to approximately 70–80°C.
and applied as a correction when calculating the test sample
8.1.6 Add sufficient 6 M NH OH to the water sample to
result.This increased background reduces the sensitivity of the
raise the pH to about 8. If bromocresol purple was added in the
measurement.
prior step this pH would be indicated by a color change to
7.2 Ammonium hydroxide, 15 M NH OH, (concentrated
purple.The needed pH change could also be measured through
reagent).
use of pH test strip or pH meter.
8.1.7 Following complete development and settling of the
7.3 Ammonium hydroxide,6MNH OH—Add 400 mL of
precipitate the supernate may be removed by aspiration or
concentrated ammonium hydroxide to 400 mLwater. Dilute to
careful decantation. The small amount of MnO precipitate
1 L with water and mix well.
maybeoptimallyisolatedintoasmallpelletbytransferringthe
7.4 Bromocresol purple pH indicator—Add 0.1 g bromo-
bottom layer containing the precipitate (about 50 mL) to a
cresol purple in 18.5 mLof 0.01 M sodium hydroxide (NaOH)
centrifuge tube and centrifuging. The precipitate may be
solution. Dilute to 250 mL with water and mix well.
further washed up to two times with water and centrifugation
repeated.
Reagent Chemicals, American Chemical Society Specifications, American
8.1.8 An alternative to centrifugation is filtration through a
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
0.45 µm filter but may require more time to accomplish the
listed by the American Chemical Society, see Analar Standards for Laboratory
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
filtration in a careful manner.
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
MD. NOTE1—Asimilarprocedurecanbeusedonacidleachatesofsediment
D8027 − 17
samples but care should be taken when adding6MNH OH to strong acid
cence will occur. Loosen cap to vent gas. Tighten cap and
solutions.
gently mix several times over a period of several minutes until
the precipitate settles and a clear supernatant appears.
8.1.9 The washed MnO precipitate and the incorporated
analytes of interest and associated isotopic tracers may be 8.2.10.4 Centrifuge the suspension and decant the superna-
taken through further separative steps, for example extraction tant. The supernatant will contain a significant fraction of the
chromatography, or may be transferred to a suitable counting calcium which was retained on the original MnO precipitate
geometry.
(thus reducing the amount of calcium retained by the MnO ).
8.2.10.5 The MnO re-precipitation described above can be
8.2 In-situ MnO Precipiation by Oxidation of Mn(II) using
repeated if necessary to further reduce calcium retained on the
H O :
2 2
MnO precipitate.
8.2.1 Anexampleofforminganin-situMnO precipitateby
oxidation of Mn(II) salt using H O is given in this section.
8.3 Screening for Naturally Occurring Radionuclides using
2 2
This example has been used to pre-concentrate radium from
MnO :
0.5 L aqueous samples for the determination of Ra and
8.3.1 MnO freshly precipitated from aqueous samples
Ra by alpha spectrometry.
effectively retains a variety of naturally occurring radionu-
8.2.2 Add an appropriate amount of Ra tracer to the
clides such as radium, thorium, uranium, polonium, actinium,
sample aliquant.
and lead. Sodium and calcium are much more weakly retained.
8.2.3 Acidify the sample using nitric or hydrochloric acid.
Freshly precipitated MnO could provide a useful approach for
An approximate acid concentration of 0.1 to 0.2 M is sug-
screening for naturally occurring alpha and beta emitters in
gested.
samples with high levels of sodium and calcium. Larger
8.2.4 Adjust the pH of the sample using phenolphthalein pH
volumes could be analyzed since most of the sodium and
indicator and 10 M NaOH to produce the first sustained pink
calcium are not retained and the mass of the MnO precipitate
color and then add a few additional drops of 10 M NaOH to
is much less than the mass of salts obtained by evaporation.
provide a basic solution with a pH between 10 and 12. Perform
Useful techniques for preparing a counting source from a
the pH adjustment and the following steps while continuously
MnO precipitate could include:
stirring on a stir plate with a magnetic stir bar.
8.3.1.1 Direct collection by filtration.
8.2.5 Add 1 mL of 0.5 M Manganese (II) chloride and mix
8.3.1.2 Dissolution with nitric acid and H O followed by
2 2
well.
evaporation on a stainless steel planchet.
8.2.6 Addapproximately2mLof30%H O usingaplastic
2 2 8.3.1.3 Dissolu
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it 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 version
of the standard as published by ASTM is to be considered the official document.
Designation: D8027 − 16 D8027 − 17
Standard Practice for
Concentration of Select Radionuclides Using MnO for
Measurement Purposes
This standard is issued under the fixed designation D8027; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This practice is intended to provide a variety of approaches in which manganese oxide (MnO ) can be used to concentrate
radionuclides of interest into a smaller volume counting geometry or exclude other species that would otherwise impede
subsequent chemical separation steps in an overall radiochemical method, or both.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 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.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D1129 Terminology Relating to Water
D7902 Terminology for Radiochemical Analyses
3. Terminology
3.1 Definitions:
3.1.1 For definitions of terms used in this standard, refer to Terminologies D1129 and D7902.
4. Summary of Practice
4.1 These practices describe different processes through which MnO can be used to concentrate specific radionuclides of
interest into a smaller volume counting geometry or exclude other species that would otherwise impede subsequent chemical
separation steps in an overall radiochemical method, or both.
4.2 Published studies (1-5) have addressed in detail the various manners in which hydrous manganese dioxides can be
synthesized and the variety of crystal forms of hydrous manganese dioxide that can result. The literature describes the following
general categories in which hydrous manganese dioxide can be prepared.
4.2.1 Guyard Reaction:
21 1
3Mn 12MnO 12H O→5MnO 14H
2 2
4.2.2 By the reduction of permanganate with reducing reagents such as hydrogen peroxide (H O ) or hydrogen chloride (HCl).
2 2
4.2.3 By the oxidation of Mn(II) salt under alkaline conditions with oxidizing reagents such as potassium chlorate (KClO ),
H O , ozone (O ), or ammonium persulfate ((NH ) S O ).
2 2 3 4 2 2 8
4.3 The presented practices are not meant to address every possible approach to the generation and use of MnO but are meant
to present some more typical practices that may be generally useful.
This practice is under the jurisdiction of ASTM Committee D19 on Water and is the direct responsibility of Subcommittee D19.04 on Methods of Radiochemical Analysis.
Current edition approved Feb. 15, 2016June 1, 2017. Published May 2016June 2017. Originally approved in 2016. Last previous edition approved in 2016 as D8027 –
16. DOI: 10.1520/D8027-16.10.1520/D8027-17.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The boldface numbers in parentheses refer to a list of references at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D8027 − 17
5. Significance and Use
5.1 This practice is applicable to the separation of specific radionuclides of interest as part of overall radiochemical analytical
methods. Radionuclides of interest may need to be quantified at activity levels of less than 1 Bq. This may require measurement
of less than 1 fg of analyte in a sample which has a mass of a gram to more than several kilograms. This requires concentration
of radionuclides into a smaller volume counting geometry or exclusion of species which would impede subsequent chemical
separations, or both. MnO has shown good selectivity in being able to concentrate the following elements: actinium (Ac), bismuth
(Bi), lead (Pb), polonium (Po), plutonium (Pu), radium (Ra), thorium (Th), and uranium (U) as noted in the referenced literature
(see Sections 4 and 8). The MnO can be loaded onto a variety of substrates in preparation for use or generated in-situ in an aqueous
solution. The presented processes are not meant to be all encompassing of what is possible or meant to address all limitations of
using MnO . Some limitations are noted in Section 6, Interferences.
6. Interferences
6.1 MnO is able to achieve a very good decontamination factor from monovalent cations in solution as evidenced by 8.38.5
below in which it is used in seawater. However, in the case of elevated concentrations of divalent cations, for example barium,
the recovery of analytes of interest can be significantly reduced (6). Additionally in the case of seawater, the recovery of analytes
such as uranium may also be substantially reduced. In such cases the use of an isotopic tracer can be very important to correct for
such reduced recovery. The MnO separation is also very conducive to being easily repeated to achieve a second stage of separation
from potentially interfering species.
7. ReagensReagents
7.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all
reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where
such specifications are available. Other grades may be used, provided that the reagent is of sufficiently high purity to permit its
use without increasing the background of the measurement.
7.1.1 Some reagents, even those of high purity, may contain naturally occurring radioactivity, such as isotopes of uranium,
radium, actinium, thorium, rare earths and potassium compounds or artificially produced radionuclides, or both. Consequently,
when such reagents are used in the analysis of low-radioactivity samples, the activity of the reagents shall be determined under
analytical conditions that are identical to those used for the sample. The activity contributed by the reagents may be considered
to be a component of background and applied as a correction when calculating the test sample result. This increased background
reduces the sensitivity of the measurement.
7.2 Ammonium hydroxide, 15 M NH OH, (concentrated reagent).
7.3 Ammonium hydroxide, 6 M NH OH—Add 400 mL of concentrated ammonium hydroxide to 400 mL water. Dilute to 1 L
with water and mix well.
7.4 Bromocresol purple pH indicator—Add 0.1 g bromocresol purple in 18.5 mL of 0.01 M sodium hydroxide (NaOH) solution.
Dilute to 250 mL with water and mix well.
7.5 Hydrogen peroxide, 30 % H O . —The ACS specification allows for a concentration range of 29 to 32 %.
2 2
7.6 Iron chloride, FeCl .
7.7 Potassium permanganate, KMnO .
7.8 Potassium permanganate, 0.5 M KMnO —Add 79 g of KMnO to 750 mL water. Dilute to 1 L with water and mix well.
4 4
7.9 Sodium hydroxide, 0.01 M NaOH—Add 0.1 g NaOH to 250 mL water.
7.10 Phenolphthalein pH indicator solution—Commercially available as 1 % solution in ethanol.
7.11 Sodium hydroxide, 10 M—Carefully dissolve 400 g of NaOH in about 900 mL of water and dilute to 1 L.
7.12 Manganese (II) chloride, 0.5 M—Dissolve 11.7 g of MnCl2•6H2O in about 80 mL of water and dilute to 100 mL.
8. Procedure
8.1 Use of MnO Generated in-situ to Pre-Concentrate Sample Analytes:
8.1.1 The precipitation of MnO from a water sample may be most conveniently performed on a volume of 0.1 to 2 L but larger
volumes are possible (7 and 8). Any isotopic tracers should be added and the valence states of the tracers and analyte species
allowed to equilibrate before proceeding.
Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by
the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National
Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.
D8027 − 17
8.1.2 Add to the water sample approximately 10 mg of KMnO and allow to dissolve. Optionally, approximately 2 mg of FeCl
4 3
may also be added to improve the obtainable separation factor.
8.1.3 The pH indicator bromocresol purple may be added to the water sample to provide a color indicator in the following step
of raising the pH.
8.1.4 Add to the water sample approximately 1 mL of about 30 % H O .
2 2
8.1.5 The precipitation step to follow is best performed at ambient temperature if a period of one or more days is available to
allow for complete settling and development of the precipitate. Alternatively the promptness of the precipitation can be assisted
by gently heating the water sample, for example to approximately 70–80°C.
8.1.6 Add sufficient 6 M NH OH to the water sample to raise the pH to about 8. If bromocresol purple was added in the prior
step this pH would be indicated by a color change to purple. The needed pH change could also be measured through use of pH
test strip or pH meter.
8.1.7 Following complete development and settling of the precipitate the supernate may be removed by aspiration or careful
decantation. The small amount of MnO precipitate may be optimally isolated into a small pellet by transferring the bottom layer
containing the precipitate (about 50 mL) to a centrifuge tube and centrifuging. The precipitate may be further washed up to two
times with water and centrifugation repeated.
8.1.8 An alternative to centrifugation is filtration through a 0.45 μm filter but may require more time to accomplish the filtration
in a careful manner.
NOTE 1—A similar procedure can be used on acid leachates of sediment samples but care should be taken when adding 6 M NH OH to strong acid
solutions.
8.1.9 The washed MnO precipitate and the incorporated analytes of interest and associated isotopic tracers may be taken
through further separative steps, for example extraction chromatography, or may be transferred to a suitable counting geometry.
8.2 In-situ MnO Precipiation by Oxidation of Mn(II) using H O :
2 2 2
8.2.1 An example of forming an in-situ MnO precipitate by oxidation of Mn(II) salt using H O is given in this section. This
2 2 2
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example has been used to pre-concentrate radium from 0.5 L aqueous samples for the determination of Ra and Ra by alpha
spectrometry.
8.2.2 Add an appropriate amount of Ra tracer to the sample aliquant.
8.2.3 Acidify the sample using nitric or hydrochloric acid. An approximate acid concentration of 0.1 to 0.2 M is suggested.
8.2.4 Adjust the pH of the sample using phenolphthalein pH indicator and 10 M NaOH to produce the first sustained pink color
and then add a few additional drops of 10 M NaOH to provide a basic solution with a pH between 10 and 12. Perform the pH
adjustment and the following steps while continuously stirring on a stir plate with a magnetic stir bar.
8.2.5 Add 1 mL of 0.5 M Manganese (II) chloride and mix well.
8.2.6 Add approximately 2 mL of 30 % H O using a plastic transfer pipette.
2 2
8.2.7 MnO precipitate (blackish color) will rapidly form and effervescence occurs.
8.2.8 Continue stirring until effervescence subsides and then allow the precipitate to settle (remove the magnetic stir bar).
8.2.9 Most of the supernatant is removed by aspiration or decantation after the precipitate has settled. Transfer the remaining
suspension to a centrifuge tube and isolate the MnO precipitate by centrifuging and decanting the supernatant. Alternatively if a
more rapid analysis is required the MnO may be isolated immediately after precipitation is complete by centrifuging in a large
volume centrifuge bottle (this eliminates the time required for settling).
8.2.10 It may be advantageous to reduce the amount of calcium retained by the MnO precipitate. For example the
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determination of Ra and Ra by alpha spectrometry can be adversely affected by excessive calcium. If calcium levels are too
high CaSO will precipitate during the Ba/RaSO microprecipitation step and spectral quality will be degraded. The following
4 4
steps describe an approach for reducing calcium retained on the MnO precipitate.
8.2.10.1 Dissolve MnO precipitate which has been collected in a centrifuge tube with 5 mL of 2 M HCl and about 0.1 mL of
30 % H O . Cap the tube and shake vigorously to facilitate dissolution.
2 2
8.2.10.2 Dilute to about 40 mL and add about 0.1 mL of 30 % H O .
2 2
8.2.10.3 Re-precipitate MnO by adding approximately
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