Standard Test Method for Hydrazine in Water

SCOPE
1.1 This test method covers² the colorimetric determination of hydrazine in boiler feed waters, condensates, natural, and well waters that have been treated with hydrazine (N2H 4 ). This test method is usable in the range from 5.0 to 200 µg/L (ppb) hydrazine. The range is for photometric measurements made at 458 nm in 50 mm cell. Higher concentrations of hydrazine can also be determined by taking a more diluted sample.  
1.2 It is the users' responsibility to ensure the validity of this test method for untested types of waters.  
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.  For specific precautionary statements, see 5.3, Note 1, and Footnote 8.

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Publication Date
09-Jun-2001
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ASTM D1385-88(2001) - Standard Test Method for Hydrazine in Water
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NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 1385 – 88 (Reapproved 2001)
Standard Test Method for
Hydrazine in Water
This standard is issued under the fixed designation D 1385; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope method, refer to Terminology D 1129.
1.1 This test method covers the colorimetric determination
4. Summary of Test Method
of hydrazine in boiler feed waters, condensates, natural, and
4.1 When a solution of p-dimethylaminobenzaldehyde in
well waters that have been treated with hydrazine (N H ). This
2 4
methyl alcohol and hydrochloric acid is added to hydrazine in
test method is usable in the range from 5.0 to 200 μg/L (ppb)
diluted hydrochloric acid solution, a characteristic yellow color
hydrazine. The range is for photometric measurements made at
of p-dimethylaminobenzalazine is formed. The yellow color
458 nm in 50 mm cell. Higher concentrations of hydrazine can
formed is proportional to the hydrazine present and is in good
also be determined by taking a more diluted sample.
agreement with Beer’s law in the range from 5.0 to 200 μg/L
1.2 It is the users’ responsibility to ensure the validity of this
(ppb) hydrazine.
test method for untested types of waters.
1.3 This standard does not purport to address all of the
5. Significance and Use
safety concerns, if any, associated with its use. It is the
5.1 Hydrazine is a man-made chemical and is not found in
responsibility of the user of this standard to establish appro-
natural waters. The determination of hydrazine is usually made
priate safety and health practices and determine the applica-
on boiler feedwaters, process waters, and other waters that
bility of regulatory limitations prior to use. For specific
have been treated with hydrazine (N H ) for the purpose of
2 4
precautionary statements, see 5.3, Note 1, and Footnote 8.
maintaining residuals to prevent corrosion by dissolved oxy-
gen. This reducing chemical reacts with dissolved oxygen to
2. Referenced Documents
form nitrogen and water. However, under certain conditions it
2.1 ASTM Standards:
3 can also decompose to form ammonia and nitrogen. Hydrazine
D 1066 Practice for Sampling Steam
is used extensively as a preboiler treatment chemical for
D 1129 Terminology Relating to Water
high-pressure boilers to scavenge small amounts of dissolved
D 1192 Specification for Equipment for Sampling Water
oxygen that are not removed by mechanical aeration. It has the
and Steam in Closed Conduits
3 advantage over sulfite treatment in that it does not produce any
D 1193 Specification for Reagent Water
dissolved solids in the boiler water. Hydrazine is often deter-
D 3370 Practices for Sampling Water from Closed Con-
3 mined in concentrations below 0.1 mg/L. However, in layup
duits
solutions for the protection of idle boilers, hydrazine may be
E 60 Practice for Photometric and Spectrophotometric
4 present in concentrations as high as 200 mg/L.
Methods for Chemical Analysis of Metals
5.2 Additionally, hydrazine provides protection to carbon
E 275 Practice for Describing and Measuring Performance
steel by chemically reducing the unprotective layers of ferric
of Ultraviolet, Visible, and Near Infrared Spectrophotom-
5 oxide (Fe O ) to a more adherent protective layer of magnetite
2 3
eters
(Fe O ).
3 4
3. Terminology 5.3 Hydrazine is a suspected carcinogen and a threshold
limit value in the atmosphere of 1.0 mg/L has been set by
3.1 Definitions—For definitions of terms used in this test
OSHA. When in an aqueous solution, hydrazine will oxidize to
nitrogen and water in the presence of air over a relatively short
This test method is under the jurisdiction of ASTM Committee D19 on Water
period of time.
and is the direct responsibility of Subcommittee D19.03 on Sampling of Water and
Water-Formed Deposits, Surveillance of Water, and Flow Measurement of Water.
6. Interferences
Current edition approved March 28, 1988. Published May 1988. Originally
published as D 1385 – 67. Last previous edition D 1385 – 86.
6.1 The substances normally present in industrial water do
For further information on this test method, the following references may be of
not interfere with the test; however, the hydrazine content may
interest: Watt, G. W., and Chrisp, J. D.,“ Spectrophotometric Method for the
be diminished by oxidizing agents, such as chlorine, bromine,
Determination of Hydrazine,” Analytical Chemistry, Vol 24, No. 12, 1952, pp.
2006–2008, and Wood, P. R., “Determination of Maleic Hydrazide Residues in Plant
and iodine, collected with the sample or absorbed by it prior to
and Animal Tissue,” Analytical Chemistry, Vol 25, No. 12, 1953, pp. 1879–1883.
testing.
Annual Book of ASTM Standards, Vol 11.01.
6.2 Colors in the prescribed wavelengths also interfere, as
Annual Book of ASTM Standards, Vol 03.05.
Annual Book of ASTM Standards, Vol 03.06. do other dark colors or turbidities that cannot be overcome.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 1385
6.3 Aromatic amines, such as aniline, will also interfere. flask and then pipetting 50 mL of the sample into the flask and
diluting to 100 mL. Prepare a blank with water at the same
7. Apparatus
time.
7.1 Photometer—A spectrophotometer suitable for mea-
9.3 A smaller sample aliquot should be taken if the hydra-
surements at 458 nm and capable of holding cells with a light
zine concentration is greater than 200 μg/L.
path of 50 mm should be used. Filter photometers and
photometric practices prescribed in this test method shall
10. Calibration
conform to Practice E 60, and spectrophotometers to Practice
10.1 Prepare a series of standard hydrazine solutions by
E 275.
pipetting 0.0, 5.0, 10.0, 25.0, 50.0, 100.0, and 200.0 mL of
7.2 Certain photoelectric filter photometers are capable of
hydrazine standard solution (1.0 mL = 0.500 μg N H ) into
measurement at 425 nm, but not at 458 nm. Measurements may
2 4
be made at 425 nm with a reduction in sensitivity of approxi- 500-mL volumetric flasks. Add 5 mL of HCl (sp gr 1.19) to
each flask and dilute with water to 500 mL and mix well. This
mately 50 % of that possible at 458 nm.
7.3 Instruments that read out in direct concentration can also will give standard solutions containing 0, 5.0, 10.0, 25.0, 50.0,
100, and 200 μg/L (ppb) of hydrazine.
be used. Manufacturer’s instructions should be followed.
10.2 Pipet 50.0-mL portions of the hy
...

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