ASTM D5108-90(2002)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D5108–90(Reapproved2002)
Standard Test Method for
Organotin Release Rates of Antifouling Coating Systems in
Sea Water
This standard is issued under the fixed designation D 5108; 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 3.2 Analysis of sea water for tributyltin is conducted by
extracting the organotin with toluene, washing with sodium
1.1 This test method covers the laboratory determination of
hydroxide, and measuring for total tin using (GF-AAS).
the rate at which organotin expressed as tributyltin (TBT) is
released from an antifouling (AF) coating in synthetic sea
4. Significance and Use
waterusinggraphitefurnaceatomicabsorptionspectrophotom-
4.1 This test method is designed to provide a laboratory
etry (GF-AAS). This does not exclude the use of other
procedure to measure changes in the release rates of solvent
analytical methodology for measurement of organotin in sea
soluble tin (tributyl- and triphenyltin) that occur during a
water such as gas chromatography.
period of immersion under specified conditions of constant
1.2 The values stated in SI units are to be regarded as
temperature, pH, salinity, and low heavy-metal concentrations
standard. The inch-pound units given in parentheses are for
in the surrounding sea water. Quantitative measurement of the
information only.
release rate is necessary to help in selection of materials, in
1.3 This standard does not purport to address all of the
providing quality assurance, and in understanding the perfor-
safety concerns, if any, associated with its use. It is the
mance mechanism.
responsibility of the user of this standard to establish appro-
4.2 This test method serves only as a guide for organotin
priate safety and health practices and determine the applica-
release rates in service. Organotin release rates of antifouling
bility of regulatory limitations prior to use. For specific hazard
(AF) paint systems in service can vary over the life of the
statements, see Section 7.
coating system depending on the formulation and the environ-
2. Referenced Documents ment. Differences in berthing locations, operating schedules,
length of service, condition of paint-film surface, temperature,
2.1 ASTM Standards:
pH, and salinity can affect results, Results obtained may not
D 1141 Practice for the Preparation of Substitute Ocean
necessarily reflect actual tributyltin release rates that will occur
Water
in service, but provide reliable comparisons of the release rate
D 1212 Test Methods for Measurement of Wet Film Thick-
3 characteristics of different antifouling formulations.
ness of Organic Coatings
4.3 This test method will serve to characterize the early
D 4138 Test Methods for Measurement of Dry Film Thick-
4 release rate pattern, as well as estimate the steady state release,
ness of Protective Coating Systems by Destructive Means
of tributyltin from both self-polishing copolymer and free-
3. Summary of Test Method association antifouling paints.
3.1 The candidate paint system is applied to cylindrical test
5. Apparatus
specimens. The coated specimens are placed in a tank of
5.1 Release-Rate Measuring Container—A2-L(nominal ⁄2
synthetic sea water where the tin levels are kept low by
gal) polycarbonate container, approximately 13.5 cm (5.5 in.)
circulating the sea water through a carbon filter. At specified
in diameter and 19 cm (7.5 in.) high, fitted with three
intervals, each specimen is placed in 1500 mL of unused sea
polycarbonate rods approximately 6 mm (nominal ⁄4 in.) in
water and is rotated for 1 h. The rate of tributyltin release from
diameter to serve as baffles. Rods shall be evenly spaced on the
the paint is determined by measuring tributyltin concentrations
inside circumference of the container to prevent swirling of
in the sea water.
water with the test cylinder during rotation. The rods will be
secured to the container walls using acetone or methylene
This test method is under the jurisdiction of ASTM Committee D01 on Paint chloride.
and Related Coatings, Materials, andApplications and is the direct responsibility of
Subcommittee D01.45 on Marine Coatings.
Current edition approved Dec. 5, 1990. Published February 1991.
2 5
Annual Book of ASTM Standards, Vol 11.02. ANalgene Container, available from Cole-Palmer, 7425 N. OakAve., Chicago,
Annual Book of ASTM Standards, Vol 06.01. IL60648, catalog number R-6761-20, or equivalent, has been found satisfactory for
Annual Book of ASTM Standards, Vol 06.02. this purpose.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D5108–90 (2002)
5.2 Constant Temperature Bath—A temperature controlled 6. Reagents and Materials
water bath capable of maintaining a temperature of 25 6 2°C
6.1 Synthetic Sea Water—Substitute ocean water in accor-
into which one or more release rate measuring test containers
dance with Section 6 of Practice D 1141 or a proprietary
can be placed.
equivalent with a salinity of 30 to 35 ppt.
5.3 Holding Tank—Acontainer of such dimensions so as to
6.2 Extraction Solvent—Toluene, spectrograde or equiva-
permit immersion of four or more test cylinders; must be
lent.
equipped with a system to continuously circulate synthetic sea
6.3 Tributyltin Standards—Prepare standards using a stock
water in the tank through a carbon filter. The rate of water flow
solution of tributyltin chloride (reagent grade, minimum 96 %
and the size of the carbon filter should be selected to maintain
pure) in methanol (suggested concentration of approximately
tributyltin concentrations below 100 µg/L. Flow rates should
10 mg/L). The standards are acidified with acetic acid (less
generally be set to obtain 2 to 8 turnovers per h. The size and
than pH 4) to obtain a stable solution.
geometry of the tanks as well as the positioning of the inflow
6.4 Hydrochloric Acid (HCl) (10 % aqueous solution).
and outflow ports for the water circulation system should be
6.5 Hydrochloric Acid (HCl) (0.1N).
selected to obtain a slow, relatively uniform flow of synthetic
6.6 Nitric Acid (HNO ) (10 % aqueous solution) can be
sea water past all test cylinders in the tank. Maintain the pH of
used in place of HCl to clean labware.
the synthetic sea water between 7.8 and 8.2, and the salinity
6.7 Sodium Hydroxide (NaOH) (3 % aqueous solution).
between 30 and 35 parts per thousand (ppt). The tank shall be
6.8 Sodium Hydroxide (NaOH) (0.1N).
provided with heaters to maintain the temperature between 21
6.9 All reagents and cleaning agents used must be tin-free.
and 27°C (70 and 81°F).
7. Hazards
5.4 Test Cylinders—Approximately 6.4 cm (nominal 2 ⁄2
7.1 Warning—Antifouling paints contain toxic materials
in.) outside diameter polycarbonate pipe coated with a 10-cm
that could cause skin and eye irritation on contact and adverse
band of AF paint around the exterior circumference of the test
physiological effects if ingested or inhaled. In the preparation
cylinder to provide 200 cm of paint film that can be immersed
of test specimens and the application of various types of paints,
and freely rotated in the release rate measuring container. Seal
the use of appropriate protective clothing and equipment is
the bottom of the test cylinder with a polycarbonate disc using
required consistent with local, state, and federal government
acetone, methylene chloride, or a polycarbonate cement so as
regulations, and recognized industrial and technical standards.
to form a watertight joint. Do not coat the bottom 1 to 2 cm of
Do not flush spills, overspray, and unused material down the
the test cylinder. The test cylinder shall be of such height so
drain, but should be dispose of as hazardous waste.
that a rotating device can be attached to rotate the cylinder and
7.2 See antifouling paint supplier’s Material Safety Data
the upper open end of the cylinder is above the level of the test
Sheet.
container immersion liquid to prevent entry of the immersion
liquid into the test cylinder.
8. Calibration and Standardization
5.5 Test Cylinder Rotating Device— The device shall be
8.1 Prepare three standards throughout the range of the
capable of rotating the test cylinder in the release rate measur-
quantification limit to 100 µg of tin per litre by dilution in
ing container at 60 6 5 r/min. No part of the device shall be
tolueneofastocksolutionoftributyltinchloride(96 %pure)in
immersed in sea water.
methanol. Include one standard with a concentration of ap-
5.6 Centrifuge Tubes, 50-mL capacity, with screw closures
proximately 50 µg of tin per litre. An alternate range of
(or disposable bottles, culture tubes, separatory funnels, etc.)
concentrations may be used when appropriate.
made of polycarbonate, TFE flourocarbon, or borosilicate
8.2 Prepare synthetic sea water spiked with three concen-
glass.
trations of TBT in the range of 10 to 50 µg of tin per litre by
5.7 Mechanical Shaker, with appropriate holders. spiking with stock solution of tributyltin chloride in methanol.
When the concentration of tin extracted in toluene exceeds 100
5.8 Dispensers, automatic or repeating, for reagents.
µg/Lappropriate dilution should be employed to keep it within
5.9 Pipets, with disposable polypropylene tips.
the limits of the calibration curve (0 to 100 µg/L).
5.10 Graphite Furnace, atomic absorption spectrophotom-
8.3 Operate the graphite furnace in accordance with manu-
eter (GF-AAS) with automatic sampler.
facturer’s instructions. Optional conditions are described in
5.11 pH Meter, with a mercury/mercurous chloride (Hg/
Appendix X1.
Hg Cl ) electrode.
2 2
8.4 Analyze the following:
5.12 Appropriate Volumetric Flasks.
8.4.1 At the beginning of each instrument run, perform
analysis of the toluene blank and standards in toluene in order
to establish that the response of the instrument is linear. Plot
separate calibration curves for each analysis of the standards
Boekel Water Baths, Models 148003 and 148004 available from Boekel
(peak height absorbance versus tin concentration), and calcu-
Industries Inc., 509-T Vine St., Philadelphia, PA 19106, or equivalent, have been
late the slope, intercept, and coefficient of determination for
found satisfactory for this purpose.
Asix-paddle stirrer, Model 300, manufactured by Whitaker Medical Mfg. Co.,
each curve using least squares regression or another appropri-
Phipps and Bird Div., 8741 Landmark Rd., Richmond,VA23228, or equivalent, has
ate procedure.
been found satisfactory for this purpose.
8.4.2 SeaWaterBlank—Extract and analyze as specified for
Oak Ridge Tubes, available from Cole-Parmer, or equivalent, have been found
satisfactory for this purpose. test samples to establish baseline.
D5108–90 (2002)
8.4.3 Spiked Sea Water Samples—Extract and analyze as tionary and positioned so that sea water moving through the
specified for test samples to determine extraction efficiency. tank will flow around each cylinder.
Recovery must be 90 to 110 %.
9.7 Monitor the pH (using a pH meter with a calomel
8.4.4 Ifchangingthegraphitetubeduringarunisnecessary,
electrode) and the temperature of the synthetic sea water in the
analyze the blank and standards in toluene to ensure proper holding tank daily. Adjust the pH if necessary using either 0.1
response and linearity before continuing the sample analysis.
N NaOH or 0.1 N HCl. Quantitate salinity every 14 days and
adjust if necessary. Determine TBT concentrations weekly.
8.5 Determine the tin concentration of individual test
samples with reference to the 50 µg/L calibrating standard When TBT levels increase, change the carbon filter before the
TBT concentration exceeds 100 µg/L. More frequent monitor-
analyzed immediately after those test samples.
ing of synthetic sea water may be necessary in Some instances
to maintain the specified environmental conditions.
9. Procedure
9.8 After 1, 3, 7, 10, 14, 21, 24, 28, 31, 35, 38, 42, and 45
9.1 Organotins have a strong tendency to adsorb on certain
days, transfer all cylinders in given batch into individual
glass or plastic surfaces. Therefore, all labware (glass or
measuring containers containing 1500 mL of fresh synthetic
polycarbonate) used for organotin release measurements must
sea water. Randomly assign cylinders (control and painted) to
betreatedasfollows:cleanthoroughlybysoakingin10 %HCl
measuring containers at each leaching. When transferring
or HNO for a minimum of 6 h. Rinse labware thoroughly with
cylinders, lift the cylinder out of the holding tank, allow sea
distilled water and allow to dry. Cleaning can also be accom-
water to drain off, install the cylinder into the rotating device,
plished by soaking in concentrated HCl for ⁄2 h. Prepare all
and submerge the painted area into the sea water. Immediately
samples, blanks, and standards in labware treated in this
start rotation of the cylinder at 60 6 5 r/min, and continue
manner. Disposable materials (pipet tips, centrifuge tubes, etc.)
rotation for 60 min. When transferring the cylinders, do not
do not have to be acid-washed before use.
touchorinanywaydamagethepaintfilm,anddonotallowthe
9.2 Prepare the exposure surfaces (200 cm ) of three repli-
paint surface to dry. Complete the transfer as quickly as
cate test cylinders to provide a suitable surface for adhesion of
possible (generally, in less than 5 min).
the paint system to be applied. Mask the surfaces to remain
9.9 If testing beyond the minimum (45 days) length require-
uncoated (including the bottom 1 to 2 cm of the exterior
ment is desired, the study may be extended to 73 days. During
circumferential surface of the test cylinder).
the extended test, remove the cylinders from the holding tank
9.3 Paints shall be manufactured a minimum of seven days
every 3 to 4 days to make a measurement of the leach rate.
prior to testing. Also, test paints shall not be allowed to age
9.10 Atthecompletionofthecylinderrotation,immediately
beyond the manufacturer’s recommended shelf life. Provide
remove the cylinder from the measuring tank and return it to
typical storage conditions during aging, that is, sealed in a
theholdingtank.Pipeta25-mLsubsampleoftheseawaterinto
container commonly used for sale and held at 20 to 30°C.
a 50-mL centrifuge tube containing sufficient 10 % HCl to
9.4 Apply one or more coats of antifouling paint to the
reducethepHto#4.0.Ifthenumberofsamplesfromtheleach
exterior circumferential surface of a test cylinder to produce a
2 measuring steps exceeds the daily analysis capacity, the
band of AF paint with an e
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