ASTM D5910-05(2012)
(Test Method)Standard Test Method for Determination of Free Formaldehyde in Emulsion Polymers by Liquid Chromatography
Standard Test Method for Determination of Free Formaldehyde in Emulsion Polymers by Liquid Chromatography
SIGNIFICANCE AND USE
4.1 With the need to calculate free formaldehyde levels in emulsion polymers, it is necessary to make the determination without upsetting any equilibria that might generate or deplete formaldehyde. This test method provides a means for determining ppm levels of free formaldehyde in emulsion polymers without upsetting existing equilibria.
SCOPE
1.1 This test method is used for the determination of free formaldehyde (HCHO) in emulsion polymers without upsetting existing formaldehyde equilibria. The procedure has been evaluated using acrylic, acrylonitrile-butadiene, carboxylated styrene-butadiene and polyvinyl acetate emulsion polymers. This test method may also be applicable for emulsion polymers of other compositions. The established working range of this test method is from 0.05 to 15 ppm formaldehyde. Emulsion polymers must be diluted to meet the working range.
1.2 This test method minimizes changes in free formaldehyde concentration that can result from changes in the physical or chemical properties of an emulsion polymer.
1.3 There are no known limitations to this test method when used in the manner described. The emulsion polymer test specimen must be prepared with a diluent that has a pH similar to that of the emulsion. Use of an inappropriate pH may upset formaldehyde equilibria and result in incorrect formaldehyde levels.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 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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Designation: D5910 − 05 (Reapproved 2012)
Standard Test Method for
Determination of Free Formaldehyde in Emulsion Polymers
by Liquid Chromatography
This standard is issued under the fixed designation D5910; 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 D2194 Test Method for Concentration of Formaldehyde
Solutions
1.1 This test method is used for the determination of free
E180 Practice for Determining the Precision of ASTM
formaldehyde (HCHO) in emulsion polymers without upset-
Methods for Analysis and Testing of Industrial and Spe-
ting existing formaldehyde equilibria. The procedure has been
cialty Chemicals (Withdrawn 2009)
evaluated using acrylic, acrylonitrile-butadiene, carboxylated
E682 Practice for Liquid Chromatography Terms and Rela-
styrene-butadiene and polyvinyl acetate emulsion polymers.
tionships
Thistestmethodmayalsobeapplicableforemulsionpolymers
of other compositions. The established working range of this
3. Summary of Test Method
test method is from 0.05 to 15 ppm formaldehyde. Emulsion
3.1 The aqueous phase of an emulsion polymer is diluted
polymers must be diluted to meet the working range.
and chromatographed on a reversed-phase octadecyl silane
1.2 This test method minimizes changes in free formalde-
(ODS) column using an aqueous mobile phase and a visible-
hyde concentration that can result from changes in the physical
light detector at 410 nm. Formaldehyde is separated from other
or chemical properties of an emulsion polymer.
species in the matrix on a chromatographic column. The
1.3 There are no known limitations to this test method when
detection system includes a post-column reactor that produces
used in the manner described. The emulsion polymer test
a lutidine derivative when formaldehyde reacts with the
specimen must be prepared with a diluent that has a pH similar
2,4-pentanedione reagent (Nash Reagent). The concentration
to that of the emulsion. Use of an inappropriate pH may upset
offreeformaldehydeinemulsionpolymersisdeterminedusing
formaldehyde equilibria and result in incorrect formaldehyde
peak areas from the standard and sample chromatograms. This
levels.
test method is specific for formaldehyde.
1.4 The values stated in SI units are to be regarded as
4. Significance and Use
standard. No other units of measurement are included in this
standard. 4.1 With the need to calculate free formaldehyde levels in
emulsion polymers, it is necessary to make the determination
1.5 This standard does not purport to address all of the
without upsetting any equilibria that might generate or deplete
safety concerns, if any, associated with its use. It is the
formaldehyde. This test method provides a means for deter-
responsibility of the user of this standard to establish appro-
mining ppm levels of free formaldehyde in emulsion polymers
priate safety and health practices and determine the applica-
without upsetting existing equilibria.
bility of regulatory limitations prior to use.
5. Interferences
2. Referenced Documents
5.1 This test method is very selective for formaldehyde.
2.1 ASTM Standards:
Potential interferants are either chromatographically separated
D1193 Specification for Reagent Water
from formaldehyde or do not react with the post-column
reagent.
This test method is under the jurisdiction of ASTM Committee D01 on Paint
NOTE 1—The following species were identified as possible interfer-
and Related Coatings, Materials, andApplications and is the direct responsibility of
ences for the method: acetaldehyde, acetone, benzaldehyde, formamide,
Subcommittee D01.33 on Polymers and Resins.
formic acid, glyoxylic acid and propionaldehyde. These species, when
Current edition approved Nov. 1, 2012. Published November 2012. Originally
chromatographed using this test method, did not interfere with the
approved in 1996. Last previous edition approved in 2005 as D5910 – 05. DOI:
formaldehyde peak at the 1000 ppm level or lower.
10.1520/D5910-05R12.
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
D5910 − 05 (2012)
5.2 Because emulsion polymers vary in composition, the
method run time may need to be extended to allow for late
eluting compounds. Compounds that remain on the column
after an analysis may interfere with the formaldehyde peak in
subsequent runs.
6. Apparatus
6.1 Liquid Chromatograph—Any liquid chromatographic
instrument having an injection valve, a post-column reactor, a
410-nm UV-Vis detector, and an isocratic solvent delivery
system may be used. The solvent delivery system must deliver
a mobile phase flow of 0.6 mL/min.
NOTE 2—The UV-Vis detector may incorporate either a tungsten lamp
or a deuterium lamp with a second order visible filter that filters out light
below 400 nm.
6.2 Post-Column Reactor—Any post-column reactor that
can deliver a reagent flow at 0.5 mL/min, contains a Knitted
Reaction Coil thatcanbeheatedto95°Candcontainsastatic
5,6
mixing tee.
6.3 Chromatographic Column—Column should be 250 by
4.6 mm inside diameter packed with a reversed-phase pH
stable C18, 5-µm particles.
6.4 Chromatographic Guard Column—The column should
be 10 by 4.6 mm inside diameter packed with a reversed-phase
pH stable C18 5-µm particles.
6.5 Data System, that can collect data at 1 point/s from a
1-V output detector.
6.6 Syringe—100 µL capacity.
6.7 Sample Filter—The filter should consist of a 5-mL
sample syringe and a 0.1-µm-filter assembly to remove micro
FIG. 1 Schematic of Liquid Chromatograph and Post-Column Re-
particulate matter from the prepared sample solution.
action Systems
6.8 Centrifuge—Any high speed centrifuge that can gener-
ate 50 000 r/min (274 980 g) or greater (Procedure 2).
8. Configuration of Post-Column Reactor (PCR)
6.9 Centrifuge—Any centrifuge that can generate 1000
8.1 The post-column reagent passes through a
9 8
r/min or greater (Procedure 3). pulsedampener andanin-linecheckvalve priortothemixing
tee.Theoutletoftheanalyticalcolumnisconnectedtooneside
7. Configuration of Liquid Chromatograph of a mixing tee. The reaction coil is connected to the outlet of
the mixing tee. Stainless steel tubing with 0.25-mm inside
7.1 An in-line check valve is placed between the pump and
diameter is used to make the connections. Tubing lengths
theinjector.Theguardandanalyticalcolumnsareconnectedto
should be kept to a minimum.The mixing tee and reaction coil
the injector.The outlet of the analytical column is connected to
are placed inside a 95°C oven. A 40 cm-length of 0.25-mm
the mixing tee as described in 8.1.
inside diameter stainless steel tubing is connected to the outlet
of the reaction coil and is placed in an ambient-temperature
stirred water bath. (This configuration acts as a heat ex-
Knitted capillary delay tube such as Supelco No. 5-9206 available from
changer.) The exit of the stainless steel tubing is connected to
Supelco Inc., Supelco Park, Bellefonte, PA 16823 has been found satisfactory for
the UV/Vis detector. Fig. 1 shows a schematic of the system.
this purpose.
Staticmixingtee,availablefromUpchurchScientific,619W.OakSt.,P.O.Box
9. Reagents and Materials
1529, Oak Harbor, WA 98277-1529, Catalog No. U-466, has been found to be
satisfactory for this purpose.
9.1 Purity of Reagents—Reagent grade chemicals shall be
Timberline RDR-1, available from Alltech Associates, Inc., 2051 Waukegan
used with this test method. Unless otherwise indicated, it is
Rd., Deerfield, IL 60015, with two 0.4-mL serpentine reaction coils in series, has
been found to be satisfactory for this purpose. intended that all reagents shall conform to the specification of
Filter such as Anotop 25 Plus Syringe Filter, 0.1 µm, Catalog No. 2270,
available from Alltech Assoc., has been found to be satisfactory for this purpose.
8 9
In-line check valve CV-3001 and U-469, Catalog No. 2270, from Upchurch Pulse dampener, SSI LO, Catalog No. 20-0218, available fromAlltechAssoc.,
Scientific has been found to be satisfactory for this purpose. has been found to be satisfactory for this purpose.
D5910 − 05 (2012)
theCommitteeonAnalyticalReagentsoftheAmericanChemi- 10.2.1 Transfer1.78gofsodiumphosphate,dibasictoa2-L
cal Society, where such specifications are available. Other mobilephasereservoirthatcontainsastirbar.Add2Lofwater
grades may be used, provided it is first ascertained that the and mix on a stir plate until the sodium phosphate, dibasic has
reagent is of sufficiently high purity to permit its use without completely dissolved.
lessening the accuracy of the determination.
10.2.2 Adjust the pH of the solution to 7.0 with 0.1 N
phosphoric acid.
9.2 Water—Unless otherwise indicated, references to water
10.2.3 Degas the mobile phase with a helium sparge.
shall be understood to mean reagent water minimally conform-
ing to Type II of Specification D1193, or distilled deionized
NOTE 5—Water may also be used as the mobile phase without the
water. High-performance liquid chromatography (HPLC) addition of a buffer.Awater mobile phase should be used when the Carrez
reagents are used in the sample preparation (see section 12.2.3).
grade water from chromatography suppliers is also acceptable.
10.3 Sample Diluent:
9.3 Acetic Acid, glacial (CH CO H).
3 2
10.3.1 Transfer0.89gofsodiumphosphate,dibasictoa1-L
9.4 Ammonium Acetate—(CH CO NH ).
3 2 4
bottle that contains a stir bar. Add 1 L of water and mix on a
9.5 Formaldehyde, 37 % (HCHO).
stir plate until the sodium phosphate, dibasic has completely
dissolved.
9.6 2,4-Pentanedione, 99 % (CH COCH COCH ).
3 2 3
10.3.2 ThefinalstepofthediluentpreparationrequiresapH
9.7 Phosphoric Acid Solution (0.1 N)—Dissolve 2.3 mL of
adjustment. Before that step can occur the pH of the emulsion
phosphoric acid 85 % (H PO ) in water and dilute to 1 L with
3 4
polymers must be measured to 0.1 pH unit. The emulsion
water.
polymers must be diluted with a buffer that is 60.1 pH unit of
9.8 Potassium Ferrocyanide Trihydrate Solution (36 g/L)
the emulsion polymer.
[Carrez Solution I]—Dissolve 26 g of potassium ferrocyanide
10.3.3 Divide the 1-L solution into the number of separate
trihydrate, 99 % (K Fe(CN) ·3H O) in water and dilute to 1 L
diluents required as mentioned in 10.3.2.
4 6 2
with water.
10.3.4 Adjust the pH of the diluents to 0.1 pH unit using
either 0.1 N NaOH or 0.1 N H PO .
9.9 Zinc Sulfate Heptahydrate (72 g/L) [Carrez Solution 3 4
II]—Dissolve 72 g of zinc sulfate heptahydrate, 99.9 %
11. Operating Conditions for Analysis
(ZnSO ·7H O) in water and dilute to 1 L with water.
4 2
11.1 Adjust the liquid chromatograph in accordance with
9.10 Sodium Hydroxide (0.1 N)—Dissolve8gof sodium
the manufacturers’ directions and the following parameters.
hydroxide 50 % (NaOH) in water and dilute to 1 Lwith water.
Allow the instrument to equilibrate until a stable base line is
9.11 Sodium Phosphate, dibasic, 98 % (Na HPO ).
2 4
obtained on the data system.
Column temperature: ambient
10. Preparation
Mobile phase: 6.3 mM Na HPO (pH = 7) or water
2 4
10.1 Post-Column Reagent (Nash Reagent):
Flow rate: 0.6 mL/min
Injection volume: 50 µL
10.1.1 Transfer 62.5 g of ammonium acetate to a 1-Lamber
12 PCR temperature: 95°C
bottle that contains a stir bar. Add 600 mL of water to the
PCR flow rate: 0.5 mL/min
bottle and mix on a stir plate until the ammonium acetate has
Detector: UV/Vis, 410 nm
completed dissolved.
11.2 Determine whether the system is working properly by
10.1.2 Pipet 7.5 mL of glacial acetic acid into the bottle.
injecting 50 µLof a 10 ppm formaldehyde standard solution.A
Pipet 5 mL of 2,4-pentanedione into the bottle. Add 387.5 mL
typical chromatogram of a 10-ppm formaldehyde standard
of water to the bottle and mix thoroughly (45 min of mixing is
obtained under the conditions outlined in 11.1 is shown in Fig.
suggested).
2. Make sure that the peak asymmetry (A at 10 % peak height)
s
value for formaldehyde is within the range of 0.8 and 1.7.
NOTE 3—2,4-Pentanedione is light sensitive and should be protected
from light during use.
Determination of peak asymmetry should be performed in
NOTE 4—The post-column reagent should be prepared weekly.
accordance with Practice E682. A typical retention time for
10.1.3 Transfer the post-column reagent to the post-column formaldehyde is 6 min.
reactor reservoir. The reservoir should be protected from light.
11.3 The run time for the analysis is 10 min. The run time
10.1.4 Degas the post-column reagent with a helium sparge.
may have to be extended 20 to 30 min if late eluting
10.2 Mobile Phase and Standard Diluent: compoundsinterferewiththeformaldehydepeakinsubsequent
runs.
Reagent Chemicals, American Chemical Society Specifications, American
12. Calibration and Standardization
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
listed by the American Chemical Society, see Analar Standards for Laboratory
12.1 Prepare a 25-mLstock solution of formaldehyde at the
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
1.18 % (11 840 ppm) level by adding 0.8 g of formaldehyde
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
MD. (37 %) to 24.2 g standard diluent.
2,4-Pentanedione (acetyl acetone), 99 %, available from Aldrich Chemical
NOTE 6—Reagent grade formaldehyde is nominally 37 %. Perform the
Co., 2905 W. Hope Ave., Milwaukee, WI 53216, Catalog No. P775-4, has been
found to be satisfactory for this method. assay of the formaldehyde solution in accordance with Test Method
A bottle that filters out ultraviolet and visible light is suitable. D2194.
D5910 − 05 (2012)
FIG. 2 Chromatogram of 10 ppm Formaldehyde Standard
in use. Prepare the stock and standard solutions weekly.
12.2 Calculate the formaldehyde concentration of the stock
solution according to the following equation:
12.5 The area under the formaldehyde peak in the chro-
Formaldehyde, ppm 5 A 310 /B (1)
~ ! matogram is considered a quantitative measure of the corre-
sponding compound.
where:
12.6 Measure the area of the formaldehyde peak by conven-
A = weight of formaldehyde, mg (corrected for active
ingredient), an
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