ASTM D3372-02(2007)e1
(Test Method)Standard Test Method for Molybdenum in Water
Standard Test Method for Molybdenum in Water
SIGNIFICANCE AND USE
Molybdenum can be found in waste that results from chemical cleaning of components in which the metal is alloyed.
National Pollution Discharge Elimination System (NPDES) permits or other standards, or both, require monitoring pollutants in waste discharged onto the water shed of, or into, navigable waters, and those disposed of in such a manner that eventual contamination of underground water could result.
This test method affords an accurate and sensitive means of determining compliance with those permits.
SCOPE
1.1 This test method covers the determination of dissolved and total recoverable molybdenum in most waters, wastewaters, and brines by atomic absorption spectroscopy.
1.2 This test method is applicable in the range from 1 to 25 g/L of molybdenum. The range may be extended by dilution of the sample.
1.3 This test method has been used successfully with natural and reagent waters. It is the user's responsibility to ensure the validity of this test method for waters of untested matrices.
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. For specific precautionary statements, see Note 3 and Note 9.
General Information
Relations
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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
´1
Designation: D3372 − 02(Reapproved 2007)
Standard Test Method for
Molybdenum in Water
This standard is issued under the fixed designation D3372; 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.
This standard has been approved for use by agencies of the Department of Defense.
´ NOTE—Sections 5.2 and 13.5 were updated editorially in September 2007.
1. Scope D5810 Guide for Spiking into Aqueous Samples
D5847 Practice for Writing Quality Control Specifications
1.1 This test method covers the determination of dissolved
for Standard Test Methods for Water Analysis
and total recoverable molybdenum in most waters,
wastewaters, and brines by atomic absorption spectroscopy.
3. Terminology
1.2 This test method is applicable in the range from 1 to 25
3.1 Definitions: For definitions of terms used in this test
µg/L of molybdenum. The range may be extended by dilution
method, refer to Terminology D1129.
of the sample.
3.2 Definitions of Terms Specific to This Standard:
1.3 Thistestmethodhasbeenusedsuccessfullywithnatural
3.2.1 laboratory control sample—a solution with the certi-
and reagent waters. It is the user’s responsibility to ensure the
fied concentration(s) of the analytes.
validity of this test method for waters of untested matrices.
3.2.2 totalrecoverablemolybdenum—anarbitraryanalytical
1.4 This standard does not purport to address all of the
term relating to the forms of molybdenum that are determin-
safety concerns, if any, associated with its use. It is the
able by the digestion procedure described in this test method.
responsibility of the user of this standard to establish appro-
4. Summary of Test Method
priate safety and health practices and determine the applica-
4.1 Molybdenum is determined by atomic-absorption spec-
bility of regulatory limitations prior to use. For specific
trophotometry. The element is chelated with
precautionary statements, see Note 3 and Note 9.
8-hydroxyquinoline, extracted with methyl isobutyl ketone,
2. Referenced Documents
and the extract aspirated into the nitrous oxide-acetylene flame
of the spectrophotometer.
2.1 ASTM Standards:
D1129 Terminology Relating to Water
5. Significance and Use
D1193 Specification for Reagent Water
5.1 Molybdenum can be found in waste that results from
D2777 Practice for Determination of Precision and Bias of
chemicalcleaningofcomponentsinwhichthemetalisalloyed.
Applicable Test Methods of Committee D19 on Water
5.2 National Pollution Discharge Elimination System
D3370 Practices for Sampling Water from Closed Conduits
D4691 Practice for Measuring Elements in Water by Flame (NPDES) permits or other standards, or both, require monitor-
ing pollutants in waste discharged onto the water shed of, or
Atomic Absorption Spectrophotometry
D4841 Practice for Estimation of Holding Time for Water into, navigable waters, and those disposed of in such a manner
that eventual contamination of underground water could result.
Samples Containing Organic and Inorganic Constituents
5.3 Thistestmethodaffordsanaccurateandsensitivemeans
1 of determining compliance with those permits.
This test method is under the jurisdiction of ASTM Committee D19 on Water
and is the direct responsibility of Subcommittee D19.05 on Inorganic Constituents
6. Interferences
in Water.
Current edition approved Aug. 1, 2007. Published September 2007. Originally
6.1 Vanadium (V) and iron (III) enhance the absorption,
approved in 1975. Last previous edition approved in 2002 as D3372 – 02. DOI:
while chromium (VI) and tungsten (VI) suppress it. These
10.1520/D3372-02R07E01.
interferences are eliminated by the addition of ascorbic acid.
Chau, Y. K., and Lum-Shue-Chan, K., “Atomic Absorption Determination of
Microgram Quantities of Molybdenum in Lake Waters,” Analytica Chimica Acta,
7. Apparatus
Vol 48, 1969, p. 205.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
7.1 Atomic-Absorption Spectrophotometer , for use at 313.3
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
nm. A general guide for the use of flame atomic absorption
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. applications is given in Practice D4691.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
D3372 − 02 (2007)
NOTE 1—The manufacturer’s instructions should be followed for all
molybdenum solution of 100 mL with water. This standard is
instrumental parameters.
used to prepare working standards at the time of analysis.
7.1.1 Molybdenum Hollow-Cathode Lamp.
8.11 Nitric Acid (sp gr 1.42)—Concentrated nitric acid
7.2 Pressure-Reducing Valves—The supplies of fuel and (HNO ).
oxidantshallbemaintainedatapressuresomewhathigherthan
8.12 Sodium Hydroxide Solution (100 g/L)—Dissolve 100 g
the controlled operating pressure of the instrument by suitable
of sodium hydroxide (NaOH) in water and dilute to 1 L.
valves.
8.13 MIBK-Saturated Water—Thoroughly mix equal vol-
8. Reagents and Materials umes of MIBK and water in a separatory funnel.Allow layers
to separate. Collect and store water and MIBK, respectively, in
8.1 Purity of Reagents—Reagent grade chemicals shall be
properly marked containers.
used in all tests. Unless otherwise indicated, it is intended that
8.14 Water-Saturated MIBK—Use MIBK prepared from
all reagents shall conform to the specifications of the Commit-
tee onAnalytical Reagents of theAmerican Chemical Society, 8.13.
where such specifications are available. Other grades may be
8.15 Nitrous Oxide—Commercially available nitrous oxide
used, provided it is first ascertained that the reagent is of
is suitable as oxidant.
sufficiently high purity to permit its use without lessening the
8.16 Acetylene Fuel—Standard, commercially available
accuracy of the determination.
acetylene is the usual fuel. Acetone, always present in acety-
8.2 Purity of Water—Unless otherwise indicated, references
lene cylinders, will affect analytical results. Generally, replac-
towatershallbeunderstoodtomeanreagentwaterconforming
ing the acetylene cylinder with 50 psig (345 kPa) remaining
to Specification D1193, Type I, II, or III water. Type I is
prevents acetone interference; however it has been reported
preferred and more commonly used. Type II water was
that cylinders with pressure at 100 psig (670 kPa) or greater
specified at the time of round robin testing of these test
will cause interference.
methods.
NOTE 3—Warning: “Purified” grade acetylene contains a special
NOTE 2—The user must ensure the type of reagent water chosen is
proprietary solvent rather than acetone and should not be used. It can
sufficiently free of interferences. The water should be analyzed using the
weaken the walls of poly(vinyl chloride) tubing that carries the acetylene
test method.
to the burner, causing a potentially hazardous situation.
8.3 Ascorbic Acid Solution (10 g/L)—Dissolve1gof
9. Sampling
ascorbic acid in water and dilute to 100 mL.
9.1 Collect the sample in accordance with Practices D3370.
8.4 Bromphenol Blue Indicator Solution (1 g/L)—Dissolve
The holding time for the samples may be calculated in
0.1 g of bromphenol blue in 100 mL of 50 % ethanol or
accordance with Practice D4841.
isopropanol.
9.2 To preserve the samples add concentrated HNO (sp gr
8.5 Hydrochloric Acid (1 + 49)—Mix 20.0 mL of concen-
1.42) to a pH of 2 or less immediately at the time of collection;
tratedhydrochloricacid(HCl,spgr1.19)withwateranddilute
normally about 2 mL/L is required. If only dissolved molyb-
to1L.
denum is to be determined, filter the samples at time of
8.6 8-Hydroxyquinoline-Methyl Isobutyl Ketone Solution
collection through a 0.45-µm membrane filter before acidifica-
(10 g/L)—Dissolve1gof 8-hydroxyquinoline in 100 mL of
tion.
methyl isobutyl ketone. Prepare fresh daily.
10. Standardization
8.7 Methyl Isobutyl Ketone (MIBK).
10.1 Prepare in 200-mL volumetric flasks a blank and
8.8 Molybdenum Solution, Stock (1.0 mL = 100 µg Mo)—
sufficient standards containing from 0.0 to 2.5 µg of molybde-
Dissolve 0.1500 g of molybdenum trioxide (MoO)in10mL
num by diluting 0.0 to 25.0-mL portions of the standard
of water containing 1 mL of NaOH (100 g/L) (warm if
molybdenum solution to 100 mL with water.
necessary). Make just acid with HCl (1 + 49) and dilute to
10.2 Proceed as directed in 11.5 to 11.11.
1000 mL with water.
10.3 Construct an analytical curve by plotting the absor-
8.9 Molybdenum Solution, Inter
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.