ISO 17191:2004

INTERNATIONAL ISO
STANDARD 17191
First edition
2004-02-01
Urine-absorbing aids for incontinence —
Measurement of airborne respirable
polyacrylate superabsorbent materials —
Determination of dust in collection
cassettes by sodium atomic absorption
spectrometry
Aides pour absorption d'urine — Dosage des particules respirables de
matériaux superabsorbants de polyacrylate en suspension dans l'air —
Dosage de la poussière dans des cassettes par spectrométrie à
absorption atomique du sodium
Reference number
©
ISO 2004
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ii © ISO 2004 – All rights reserved

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 17191 was prepared by Technical Committee ISO/TC 173, Technical systems and aids for disabled or
handicapped persons, Subcommittee SC 3, Aids for ostomy and incontinence.
Introduction
This International Standard was originally developed by European Disposables and Nonwovens Association
(EDANA) as one of a twelve part series of test methods. It specifies a test method for determining the amount
of airborne dust emanating from polyacrylate superabsorbent material. The other eleven parts differ from
ISO 17191 in that they cover test methods for the characterization of polymer-based absorbent materials.
They have been transformed into International Standards as a series of eleven parts of ISO 17190.
This test method has been in practical use for several years, and has proven to be reliable with respect to
common criteria of quality of test methods (validity, repeatability, etc.). It is applicable to polyacrylate
superabsorbent materials, which occur in hygiene products including urine-absorbing aids for incontinent
persons. The test methods are addressed to the material exclusively. They are not intended to be used, and
are not applicable for use, with finished manufactured urine-absorbing aids.

iv © ISO 2004 – All rights reserved

INTERNATIONAL STANDARD ISO 17191:2004(E)

Urine-absorbing aids for incontinence — Measurement of
airborne respirable polyacrylate superabsorbent materials —
Determination of dust in collection cassettes by sodium atomic
absorption spectrometry
1 Scope
This International Standard specifies a method for the determination of polyacrylate (PA) superabsorbent
powders in airborne dust by measurement of sodium (Na) by atomic absorption spectrometry (AAS). PA dust
samples are collected in polystyrene acrylonitrile air-monitoring cassettes with polytetrafluoroethylene filters
and porous plastic backing pads.
This method is applicable to the determination of collected superabsorbent powder in the range between
0,2 µg and 60 µg (limit of detection near 0,2 µg) of superabsorbent powders.
NOTE This test is designed to determine low levels of sodium and requires that very clean handling conditions be
observed. The use of deionized/distilled water containing very low sodium content is critical for successful analysis.
2 Normative references
The following referenced documents are indispensable for the application 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 3696:1987, Water for analytical laboratory use — Specification and test methods
3 Principle
Atomic absorption analysis is used to determine the sodium content in PA superabsorbent powders collected
in air-monitoring cassettes. The sodium is determined after being released from the PA superabsorbent
powder by exchange with potassium in a potassium chloride solution. The amount of dissolved sodium is then
determined using AAS, and the mass of the PA superabsorbent powder collected is calculated after
subtracting the background sodium levels present in blank cassettes.
To minimize sodium contamination, cassettes are prewashed before collecting the airborne superabsorbent
powder. For the analysis, an aliquot of the potassium chloride solution is drawn from the cassette directly into
the atomic absorption spray chamber.
4 Reagents
Use only reagents of recognized analytical grade, unless otherwise specified. Store all reagents and solutions
in plastic containers with the exception of KCl (4.5) and IPA (4.3). Store these in the glass containers in which
they are shipped.
Pre-analyse reagents and solutions as specified in 4.1, 4.2 and 4.3 for sodium (Na) using AAS, before using
to clean cassettes or for Na analysis.
4.1 Potassium chloride (KCl), KCl content 99,999 % minimum; Na concentration less than 10 µg/g.
4.2 Water, deionized or distilled, in accordance with ISO 3696:1987, Grade 1, containing < 0,1 mg/l of Na.
4.3 Isopropanol (IPA), analytical reagent grade.
1)
4.4 Sodium standard reference solution, r(Na) = 1 000 mg/l [1 000 ppm ].
4.5 Potassium chloride solution, r(KCl) = 2 000 mg/l.
Dissolve 2,0 g of potassium chloride (4.1) in 1 l of deionized water (4.2) in a polypropylene flask. The solution
shall contain < 0,1 mg/l of Na.
4.6 Sodium standard solutions, for AAS as follows: r(Na) = 0,1 mg/l, 0,5 mg/l, 1,0 mg/l, 2,0 mg/l.
Using polypropylene volumetric flasks, dilute the 1 000 mg/l sodium standard reference solution (4.4) with the
2 000 mg/l potassium chloride solution (4.5) as required, and add isopropanol (4.3) to obtain a solution of
10 % by volume.
4.7 Atomic absorption zeroing solution,
Add isopropanol (4.3) to 2 000 mg/l potassium chloride solution (4.5) to obtain a solution of exactly 10,0 %
isopropanol by volume.
5 Apparatus
5.1 Atomic absorption spectrometer (AAS).
Use a single-beam spectrometer with air-acetylene flame, or equivalent, capable of photometric accuracy of
± 0,0005 AU.
5.2 Spraychamber and burner: use a unit that is dedicated for trace-level sodium determination.
5.3 Hollow cathode lamp for sodium.
5.4 Pipette, capable of measuring 0,5 ml.
5.5 Pipette, capable of measuring 4,5 ml.
5.6 Plastic gloves, non-powdered.
5.7 Volumetric flasks, polypropylene, 1 000 ml and 100 ml capacity.

2)
5.8 Air-monitoring cassettes , see Figure 1.
5.9 Flatbed laboratory shaker, capable of holding and shaking air-monitoring cassettes (5.8)

1) 1 mg/l = 1 ppm. The use of ppm is deprecated.
2) Commercially available air-monitoring cassettes with the following specifications have been shown to be suitable:
three-piece clear polystyrene cassette for respirable dust cyclone sampling, as specified in NIOSH methods 7500 & 0600,
37 mm diameter, with porous high density polyethylene or PTFE support pad [e.g. cassette SKC catalogue part No. 225-3;
support pad = SKC catalogue part No. 225-2902; filter = PTFE filter with PTFE support, 37 mm diameter, 2 µm thickness,
typical air flow 25,3 l/min/cm at 0,7 bar pressure drop, typically 99,99 % aerosol retention (e.g. Pall Gelman catalogue
part No. P5pj037, Zefluor filter 37 mm, 2 µm)] . This information is given for the convenience of the users of this
International Standard and does not constitute an endorsement by ISO of these products.
2 © ISO 2004 – All rights reserved

3)
5.10 Air filter , for drying assembly manifold (see Figure 2), capable of retaining airborne particles and
aerosols of > 0,3 µm diameter at a minimum flowrate of 5 l/min.

Key
1 air flow 4 filter
2 cassette outlet 5 cassette ring (middle)
3 support pad 6 cassette ring (bottom)
Figure 1 — Air-monitoring cassette

3) Commercially available High Efficiency Particulate-free Air (HEPA) capsule with the following specification has been
shown to be suitable: Pall Corporation, catalogue No. 12144. This information is given for the convenience of the users of
this International Standard and does not constitute an endorsement by ISO of this product.
Key
1 HEPA filter
2 cassette
3 Tygon tubing
a
To vacuum.
Figure 2 — Cassette-drying unit
6 Procedure
6.1 Sample preparation and precautionary measures
6.1.1 Preparation and cleaning of cassettes prior to air monitoring
6.1.1.1 In summary, cassettes are assembled, filters are wet with 0,5 ml IPA, washed with 0,2 % KCl
solution, then rinsed with de-ionized water and dried before use as dust collection devices or blanks.
6.1.1.2 Assemble the desired number of cassettes without touching with the fingers any inside surface of
the cassette. Analysts may wear plastic gloves to reduce contamination. Use forceps to handle filters and
backing pads. If filters or backing pads are dropped, they should be discarded. Wash any hardware before re-
use if dropped. Put only the bottom-end plug in the cassette, keeping the other plugs in the plastic bag. Tape
the cassette over the circumference at the joint to assure a good seal.
6.1.1.3 Add 0,5 ml of IPA to the cassette to wet the filter and fill the cassette with 0,2 % KCl. Allow the
KCl solution to stand in the cassette for at least 15 min, but not longer than 2 h.
6.1.1.4 Using vacuum suction (Figure 3), draw the solution through the cassette. Turn-off the vacuum just
as the cassette empties. Do not pull air through the cassette after the solution has been drawn out. Fill the
cassette with deionized water and pull through to rinse the cassette. Repeat this three more times.

4 © ISO 2004 – All rights reserved

Key
1 Tygon tubing
a
Put cassette here.
b
To vacuum.
Figure 3 — Vacuum washing stand
6.1.1.5 After the last rinse, connect the inlet of the cassette to an HEPA (High Efficiency Particulate-free
Air) filter with retains particles and aerosols with diameters in excess of 0,3 µm. For efficiency, up to six
cassettes may be fitted in parallel to the same HEPA filter (see Figure 2). Using vacuum suction, pull air
through the cassette for drying. The required time will vary for each cassette, but experience has shown that
all visible water is removed after 2 h if the air flow rate is 0,85 l/min for each cassette. Excess drying is not
recommended in order to minimize contamination risk. The filter appearance will change to a bright white
when dry, and all water droplets will be evaporated from the interior of the cassettes.
6.1.1.6 Fit the inlet and outlet plugs in the cassette with forceps; do not touch the plugs with the fingers.
Tighten the plugs by turning and pressing by hand. Re-inspect the cassettes after 12 h for signs of moisture. If
moisture is seen, dry for as short time as possible (as in 6.1.1.5) to remove the moisture. If a cleaned cassette
is accidentally opened, it should be recleaned before use.
6.1.1.7 Before releasing cleaned cassettes for air sampling, each shall be clearly labelled with a unique
identification so that its preparation date can be traced. In addition, 10 % of the cassettes shall be tested for
sodium contamination. These cassettes shall be selected from the first, middle and last part of the batch.
Cassettes are tested for contamination as if they were samples from air monitoring. If the test cassettes
contain over 0,17 µg of sodium, then all cassettes shall be re-cleaned and again 10 % shall be tested before
release.
Keep records of the absorbance values of the water used for rinsing, and the values from the sodium
determination for the 10 % blank cassettes that were tested.
6.1.1.8 In addition to the cassettes that are tested for release, five of the remaining clean cassettes
should be retained for blank determinations. These are for determining the limit of detection for the test at the
time a series of cassettes from
...