ISO 17190-10:2020

INTERNATIONAL ISO
STANDARD 17190-10
Second edition
2020-10
Urine-absorbing aids for
incontinence — Polyacrylate
superabsorbent powders —
Part 10:
Test method for determination of
extractable polymer content by
potentiometric titration
Aides pour absorption d'urine — Méthodes d'essai pour caractériser
les matériaux absorbants à base de polymères —
Partie 10: Détermination de la teneur en polymère extractible par
titrage potentiométrique
Reference number
©
ISO 2020
© ISO 2020
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Published in Switzerland
ii © ISO 2020 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Reagents and materials . 2
6 Apparatus . 2
7 Conditioning . 4
8 Sampling . 4
9 Procedure. 4
10 Calculation . 5
11 Report . 6
12 Precision . 7
Bibliography . 8
Foreword
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iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 173, Assistive products, Subcommittee SC
3, Aids for ostomy and incontinence.
This second edition cancels and replaces the first edition (ISO 17190-10:2001), which has been
technically revised. The main changes compared to the previous edition are as follows:
— full text review and new laboratory analysis with statistical evaluation.
A list of all parts in the ISO 17190 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2020 – All rights reserved

INTERNATIONAL STANDARD ISO 17190-10:2020(E)
Urine-absorbing aids for incontinence — Polyacrylate
superabsorbent powders —
Part 10:
Test method for determination of extractable polymer
content by potentiometric titration
WARNING — This document does not claim to address all of the safety concerns, if any, associated
with its use. It is the responsibility of the user of this document to establish appropriate safety
and health practices and determine the applicability of regulatory limitations prior to use. It
is expected that the person performing this test has been fully trained in all aspects of this
procedure.
1 Scope
This document provides a test method to determine the mass fraction of soluble polymers present in
crosslinked polyacrylate superabsorbent powders that can be extracted into saline solution.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 187, Paper, board and pulps — Standard atmosphere for conditioning and testing and procedure for
monitoring the atmosphere and conditioning of samples
ISO 3696, Water for analytical laboratory use — Specification and test methods
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
extractables
sum of the soluble acid and salt groups of monomeric, oligomeric and polymeric carboxylates extracted
from the superabsorbent polymer
3.2
sample
product or portion of a product taken from a production lot for testing purposes and identifiable and
traceable back to its origin
4 Principle
The amount of extractable polymer in polyacrylate superabsorbent powders is determined by mixing
the polymer in saline solution for 1 hour. The resulting saline suspension is filtered in its entirety
through a paper filter of <12 µ pore size. An aliquot of the filtrate is titrated against a standard
base solution (NaOH) to pH 10,0 to determine the concentration of free carboxylic acid groups. The
resulting solution is then back-titrated against a standard acid solution (HCI) to pH 2,7 to determine
the concentration of neutralized carboxylate groups. The titration data are used to calculate the total
amount of extractables present in the superabsorbent powder.
5 Reagents and materials
Use only reagents of recognized analytical grade, unless otherwise specified.
5.1 Water.
Grade 3 water in accordance with ISO 3696, with the exception that the conductivity can be as high as
30 μS/cm.
5.2 Sodium hydroxide solution.
c(NaOH) = 0,1 mol/l. Obtained as ready-made analytical grade solution.
5.3 Hydrochloric acid solution.
c(HCl) = 0,1 mol/l. Obtained as ready-made analytical grade solution.
5.4 Sodium chloride solution.
5.4.1 0,9 % mass fraction of sodium chloride solution in water. Weigh (9,00 ± 0,01) g of sodium chloride
into a 1 l beaker and add (991,0 ± 0,1) g of deionized water (grade 3). Stir until dissolved.
5.4.2 The conductivity of the solution should be checked prior to each use using properly calibrated
measuring equipment. The expected conductivity of a 0,9 % saline solution is of the order of 16mS/cm at
25 °C. Each testing lab shall determine the correct conductivity for the conditions obtaining in the lab. It
is also recommended that the temperature of the solution be maintained at (23 ± 2) °C for the duration
of the test. As this matches the required laboratory temperature it is not necessary to record the solution
temperature.
5.5 Standard buffer solutions.
Prepare 3 buffer solutions in accordance with ISO 10523 with pH values suitable to work in a range
from pH 2,7 till pH 10. For instance
— 3,0 ± 0,02
— 7,0 ± 0,02
— 10,0 ± 0,02
6 Apparatus
6.1 Analytical balance, capable of weighing a mass of (1,000 ± 0,001) g of polymer powder in
combination with the mass of the weighing vessel or laboratory paper employed.
2 © ISO 2020 – All rights reserved

6.2 Analytical balance, capable of weighing a mass of (9,00 ± 0,01) g of sodium chloride in combination
with the mass of the weighing vessel or laboratory paper employed.
6.3 Analytical balance, capable of weighing a mass of (1 000,00 ± 1,00) g of sodium chloride solution
in combination with the mass of the vessel employed
6.4 pH meter with a combined glass pH-responsive electrode, referred to in the text as the pH
electrode, which is suitable for titrating polymer solutions and capable of accurately measuring pH in the
range 2,7 to 10,0. For example, a large membrane surface increases the electrode sensitivity for high pH
measurement and a leaky sleeve electrode is less likely to suffer contamination from the polymer in the
titration solution.
6.5 Volumetric flask, grade “A” of 1 l capacity.
6.6 Weighing vessel or laboratory paper.
6.7 Titration vessels - glass beakers or conical flasks.
6.8 Conical flask, of 250 ml capacity.
6.9 Beaker, of 250 ml capacity. A tall form is recommended to allow better gel separation.
6.10 Metal spatula, to accommodate 1,0 g of superabsorbent powder.
6.11 Paraffin film or suitable cover for glass beakers.
6.12 Filter papers, to accommodate 100 ml supernatant, with a pore size <12 µm.
6.13 Measuring cylinder, of 200 ml capacity and accurate to ±0,5 %.
-1
6.14 Magnetic stirrer, having the capability of stirring at a rate of 250 ± 50 r.min .
6.15 Magnetic stirrer and stirring bar.
6.16 Cylindrical stirring bars can be unstable when used on a multipoint magnetic stirring block.
The mixture of magnetic fluxes can cause the bar to freeze periodically. Both cylindrical and star-shaped
stirrers can tear the gel. It is recommended to use a cross-centred circular bar (see Figure 1), which
provides more stable stirring and minimum tearing of the gel. It is also important to make sure that
the cross is properly centred in the circle. Cheaply made versions can be off-centre and this increases
variability in the test.
Figure 1 — Cowie double cross-head stir bar (typical dimensions: 20 < d < 25 mm,
12 < h < 18 mm)
6.17 Analytical burette, of 10 ml to 20 ml volume, with an accuracy to ±0,01 ml or automated titration
equipment of similar or better accuracy.
7 Conditioning
Samples shall be delivered in a closed container, to prevent absorption of atmospheric moisture. Allow
the closed container to equilibrate to the laboratory conditions. The preferred test conditions are
(23 ± 2) °C and (45 ± 15) % relative humidity. If these conditions are not available, test at ambient
conditions and report the temperature and relative humidity. Measure these laboratory conditions in
accordance with ISO 187.
8 Sampling
WARNING — Powder Handling – The German Commission for the Investigation of Health
Hazards of Chemical Compounds in the Work Area (MAK Commission) has provided a guideline
value for long-term exposure to the respirable portion of superabsorbent polyacrylate dust
-3
of 0,05 mg.m . The respirable portion is defined as those particles of less than 10 µm diameter.
...