ISO 6850:1994

INTERNATIONAL
IS0
STANDARD
6850
First edition
1994-l 2-l 5
Processing wastes -
Photography -
Determination of nitrate by a spectrometric
method using brucine
D6 termina tion de la teneur en nitrate
Photographie - Effluents de traitement -
par une m&hode spectromktrique ;i la brucine
Reference number
IS0 6850:1994(E)

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Foreword
IS0 (the International Organization for Standardization) is a worldwide
federation of national standards bodies (IS0 member bodies). The work of
preparing International Standards is normally carried out through IS0
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. IS0
collaborates closely with the International Electrotechnical Commission
(IEC) on all matters of electrotechnical standardization.
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.
International Standard IS0 6850 was prepared by Technical Committee
ISOfTC 42, Photography.
0 IS0 1994
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means electronic or mechanical, including photocopyrng and
microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case postale 56 l CH-1211 Geneve 20 l Switzerland
Printed in Switzerland

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0 IS0 IS0 6850: 1994(E)
Introduction
This International Standard is one a series devoted to the analysis of
photographic wastes; it encompasses the field of analysis of nitrate ions in
photographic effluents.
This International Standard is intended for use by individuals with a
working knowledge of analytical techniques, which may not always be the
case. Some of the procedures utilize caustic, toxic or otherwise hazardous
chemicals. Safe laboratory practice for the handling of chemicals requires
the use of safety glasses or goggles, rubber gloves and other protective
apparel such as face masks or aprons where appropriate. Normal
precautions required in the performance of any chemical procedure are to
be exercised at all times but care has been taken to provide warnings for
hazardous materials. Hazard warnings designated by a letter enclosed in
angle brackets, < >, are used as a reminder in those steps detailing
handling operations and are defined in clause 4. More detailed information
regarding hazards, handling and use of these chemicals may be available
from the manufacturer.
In the case of effluents, the photographic laboratory can best establish its
conformity to regulations by appropriate chemical analysis. In some cases,
in-house analyses will be possible; often the use of an outside laboratory
will be required.
..e
III

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IS0 6850: 1994(E)
INTERNATIONAL STANDARD o IS0
Photography - Processing wastes - Determination of nitrate by a
spectrometric method using brucine
1 Scope sequence and by subsequent incubation of the
reaction mixture for a precise interval of time at a
known temperature.
This International Standard specifies a spectrometric
in
method for the determination of nitrates
photographic processing wastes. Pretreatment of the The sample is pretreated to remove interferences in
sample is necessary to remove interferences present photographic processing wastes. Sodium arsenite
in photographic processing wastes. solution is added to the sample to eliminate any
residual chlorine present in the sample. Sulfanilic acid
in the brucine reagent eliminates nitrite interference.
This method can be applied to samples containing
The sample is then reacted with brucine reagent,
nitrate in the concentration range 4,4 mg/l to 88 mg/l
acidified with sulfuric acid, and incubated for exactly
of nitrate (1 mg/l to 20 mg/l of nitrogen).
20 min in a boiling water bath. The absorbance of the
coloured sample is measured at 410 nm.
2 Normative references
The following standards contain provisions which,
4 Safety and operational precautions
through reference in this text, constitute provisions of
this International Standard. At the time of publication,
4.1 Hazard warnings
the editions indicated were valid. All standards are
subject to revision, and parties to agreements based
Some of the chemicals specified in the test
on this International Standard are encouraged to in-
procedures are caustic, toxic or otherwise hazardous.
vestigate the possibility of applying the most recent
Specific danger notices are given in the test and
editions of the standards indicated below. Members
footnotes for particularly dangerous materials, but
of IEC and IS0 maintain registers of currently valid
are required during the
normal precautions
International Standards.
performance of any chemical procedure at all times.
The first time that a hazardous material is noted in the
IS0 6353-l : I 982, Reagents for chemical analysis -
test procedures, the hazard will be indicated by the
Part I: General requirements.
word “DANGER” followed by a symbol consisting of
angle brackets “c 9’ containing a letter which des-
IS0 6353-2: 1983, Reagents for chemical analysis -
ignates the specific hazard. A double bracket I ’<< >>”
Part 2: Specifications - First series.
will be used for particularly perilous situations. In
subsequent statements involving handling of these
IS0 6353-3: 1987, Reagents for chemical analysis - only the hazard symbol
hazardous materials,
Part 3: Specifications - Second. series.
consisting of the brackets and letter(s) will be
for a given material, the
displayed. Furthermore,
IS0 10349-I :I 992, Photography - Photographic- hazard symbol will be used only once in a single
grade chemicals - Test methods - Part 1: General. paragraph.
Detailed warnings for handling chemicals and their
diluted solutions are beyond the scope of this Inter-
3 Principle
national Standard.
The reaction between nitrate and brucine produces a
yellow colour, the intensity of which is measured at
Employers shall provide training and health and
410 nm. The reaction rate between brucine and
safety information in conformance with legall re-
nitrate ions and hence the intensity of the colour
quirements.
formed is affected significantly by the amount of heat
generated during the test. Thus the procedure seeks The hazard code system defined in this International
to control the heat by optimizing the reagent addition Standard is intended to provide information to the
1

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IS0 6850: 1994(E) 0 IS0
users and is not meant for compliance with any legal
5.12 Purity
requirements for labelling as these vary from country
to country.
Reagents used in the test procedures shall be certi-
fied reagent-grade chemicals and shall meet appro-
It is strongly recommended that anyone using priate standards or be chemicals of a purity accept-
these chemicals obtain from the manufacturer able for the analysis. For details see IS0 6353-1,
pertinent information about the hazards, handling, IS0 6353-Z and IS0 6353-3.
use and disposal of these chemicals.
Whenever water is specified without other qualifiers
in the test procedures, only distilled water or water of
equal purity shall be used.
4.2 Hazard information code system
Harmful if inhaled. Avoid breathing dust,
51.3 Strength of solutions
vapour, mist or gas. Use only with adequate
ventilation.
5.1.3.1 Acids and ammonium hydroxide are full
strength unless otherwise specified.
Harmful if contact occurs. Avoid contact

with eyes, skin or clothing. Wash thoroughly
5.1.3.2 When a standardized solution is required, its
after handling.
concentration is expressed as molarity (mol/l). The
number of significant figures to which the molarity is
Harmful if swallowed. Wash thoroughly after
known shall be sufficient to ensure that the reagent
handling. If swallowed, obtain medical
does not limit the reliability of the test method.
attention immediately.
5.1.3.3 When a standardized solution is not required,
<> May be fatal if swallowed. If swallowed,
its concentration is expressed in grams per litre (g/l) to
obtain medical attention immediately.
the appropriate number of significant figures.
Will burn. Keep away from heat, sparks and
5.1.3.4 When a solution is to be diluted, its dilution is
open flame. Use with adequate ventilation.
indicated by (X + Y), meaning that X volumes of
reagent, or concentrated solution, are to be diluted
Oxidizer. Contact with other material may

with Y volumes of distilled or deionized water.
cause fire. Do not store near combustible
materials.
5.2 Reagents
4.3 Safety precautions
5.2.1 Brucine reagent
All pipette operations SHALL BE PERFORMED
Brucine/sulfanilic acid stock solution
5.2.1 .I
WITH A PlPElTE BULB OR PLUNGER PIPETTE.
THIS IS A CRITICAL SAFETY WARNING!
Dissolve I,00 g t, 0,Ol g of brucine sulfate
[(C23H26N204)2 ’2H2S04.7H*O] (DANGER: <>)
Safety glasses shall be worn for all laboratory
and OJO g * 0,Ol g of sulfanilic acid (CGH,NSOs.HZO)
work.
in 70 ml of hot water in a 150 ml beaker. Then add,
from a tip-up pipette (6.6), 3 ml of hydrochloric acid,
= 1 ,I8 g/ml (DANGER: cB>), cool and dilute to
P
100 ml. This stock solution shall be stored in a
5 Materials and reagents
refrigerator, where it is stable for several months.
5.1 General
5.2.1.2 Preparation
5.1 .I Handling and labelling
Prepare the brucine reagent by mixing 25 ml of the
brucine/suIfaniIic acid stock solution (DANGER:
Reagents shall be handled in conformity with health
<>) (5.21 .I) and 125 ml of the sodium
and safety precautions as shown on containers or as
chloride (5.2.7). This reagent shall be prepared fresh
given in other sources of such information. Proper
each day.
labelling of prepared reagents includes chemical
name, date of preparation, expiration date, restan-
dardization date, name of preparer, and adequate
5.2.2 Decolorizing charcoal
health and safety precautions. The discharge of re-
agents shall comply with applicable environmental
5.2.3 Filter aid (diatomaceous earth).
regulations
2

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0 IS0 IS0 6850: 1994(E)
5.2.4 Standard nitrate solutions 1 litre one-mark volumetric flask. Dissolve by stirring
on a magnetic stirrer, and dilute to the mark with
water.
Prepare these from a stock solution of potassium
nitrate containing 4,4 g/l nitrate ion (1 g/l of nitrogen)
which is prepared from 7,175 g ~lt 0,001 g of dried
5.2.7 S
...