EN ISO 7980:2000

SLOVENSKI STANDARD
01-december-2000
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SIST ISO 7980:1997
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Water quality - Determination of calcium and magnesium - Atomic absorption
spectrometric method (ISO 7980:1986)
Wasserbeschaffenheit - Bestimmung von Calcium und Magnesium - Verfahren mittels
Atomabsorptionsspektrometrie (ISO 7980:1986)
Qualité de l'eau - Dosage du calcium et du magnésium - Méthode par spectrométrie
d'absorption atomique (ISO 7980:1986)
Ta slovenski standard je istoveten z: EN ISO 7980:2000
ICS:
13.060.50 3UHLVNDYDYRGHQDNHPLþQH Examination of water for
VQRYL chemical substances
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

International Standard
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION.MEXKLIYHAPOfiHAR OPrAHM3ALWlfI fl0 CTAH~APTM3AL&Wl~RGANISATION INTERNATIONALE DE NORMALISATION
Determination of Calcium and
Water quality -
Atomic absorption spectrometric method
magnesium -
M&hode par spectrom&rie d’absorption atomique
Qualit& de l’eau - Dosage du calcium et du magnesium -
First edition - 1986-05-01
UDC 543.3 : 543.422 : 546.41: 546.46 Ref m No. ISO 7980-1986 (E)
determination of content, Calcium, magnesium, spectrochemical analysis.
Descriptors : water, quality, Chemical analysis,
Price based on 3 pages
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of
national Standards bodies (ISO member bedies). The work of preparing International
Standards is normally carried out through ISO technical committees. Esch 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, govern-
mental and non-governmental, in liaison with ISO, also take part in the work.
Draft International Standards adopted by the technical committees are circulated to
the member bodies for approval before their acceptance as International Standards by
the ISO Council. They are approved in accordance with ISO procedures requiring at
least 75 % approval by the member bodies voting.
International Standard ISO 7980 was prepared by Technical Committee ISO/TC 147,
Water quality.
Users should note that all International Standards undergo revision from time to time
and that any reference made herein to any other International Standard implies its
latest edition, unless otherwise stated.
0 International Organization for Standardization, 1986 l
Printed in Switzerland
ISO 79804986 (EI
INTERNATIONAL STANDARD
Water quality - Determination of Calcium and
magnesium - Atomic absorption spectrometric method
To a 1 litre one-mark volumetric flask add 24 g of lanthanum
Scope and field of application
Oxide ( La203) (atomic absorption spectrometry grade). Slowly
and cautiously add 50 ml of hydrochloric acid (3.1) while
This International Standard specifies a method for the deter-
stirring to dissolve the lanthanum Oxide. Make up to the mark
mination of dissolved Calcium and magnesium by flame atomic
with water.
absorption spectrometry. lt is intended for the analysis of raw
and drinking waters and tan be used for waters having a
3.4 Caesium chloride (CsCI) Solution, containing 20 g of Cs
Calcium content of up to 50 mg/l and a magnesium content of
per litre.
up to 5 mg/l. For samples containing higher concentrations of
Calcium or magnesium a smaller volume of the Sample must be
taken for the analysis. Dissolve 25 g of caesium chloride in 1 litre of hydrochloric
acid (3.2).
When using the air/acetylene flame and the dilution factor 1 in
10, as described in 6.1, the Optimum range is 3 to 50 mg/1 for
3.5 Calcium, stock Solution, 1 000 mg/l.
Calcium and 0,9 to 5 mg/l for magnesium.
Dry a Portion of Calcium carbonate (CaC03) at 180 OC for 1 h
and allow it to cool in a desiccator. Weigh 2,50 + 0,Ol g of the
dried material and suspend this in 100 ml of water. Add slowly
2 Principle
the minimum amount of hydrochloric acid (3.2) necessary to
dissolve the Calcium carbonate (approximately 250 ml). Boil
Measurement by flame atomic absorption spectrometry after
briefly to expel dissolved carbon dioxide, then cool. Transfer
adding lanthanum chloride (if an air/acetylene flame is used) or
the Solution quantitatively to a 1 000 ml one-mark volumetric
caesium chloride (if a nitrous oxide/acetylene flame is used) to
flask and make up to the mark with hydrochloric acid (3.2).
reduce interferences. For Calcium the absorbance is measured
at 422,7 nm and for magnesium at 285,2 nm.
Store the Solution in a polyethylene or polypropylene bottle.
3.6 Magnesium, stock Solution, 1 000 mg/l.
3 Reagents and materials
Dry a Portion of magnesium Oxide (MgO) at 180 OC for 1 h.
Weigh 1,66 & 0,Ol g and dissolve in hydrochloric acid (3.2).
During the analysis, use only reagents of recognized analytical
Dilute with the same acid to 1 000 ml in a one-mark volumetric
grade and only distilled water or water of equivalent purity.
flask.
(Commercially available, ready-made solutions may by used.)
Store the Solution in a polyethylene bottle.
3.1 Hydrochlorit acid (HCI), Q = 1,18 g/ml.
3.7 Calcium-magnesium, Standard Solution corresponding
3.2 Hydrochlorit acid (HCI), 0,l mol/l.
to 20 mg of Ca and 2 mg of Mg per litre.
Dilute 8 ml of hydrochloric acid (3.1) to 1 litre.
With pipettes, transfer 20,O ml of the Calcium stock Solution
(3.5) and 2,0 ml of the magnesium stock Solution (3.6) to a
1 000 ml one-mark volumetric flask. Make up to the mark with
3.3 Lanthanum chloride (LaCl$ Solution, containing 20 g
hydrochloric acid (3.2).
of La per litre.
ISO 7980-1986 (E)
Prepare a relevant number of 100 ml one-mark volumetric
4 Apparatus
flasks. To each of these add 10 ml of the lanthanum chloride
Usual laboratory equipment, and Solution (3.3) if an air/acetylene flame is to be used, or 10 ml of
the caesium chloride Solution (3.4) if a nitrous oxide/acetylene
Atomic absorption spectrometer, set up
...