1973L0046 — EN — 26.05.1999 — 004.001 — 1
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►B FOURTHCOMMISSIONDIRECTIVE
of5December 1972
establishingCommunitymethodsofanalysisfortheofficial controloffeedingstuffs
(73/46/EEC)
(OJ L 83, 30.3.1973, p. 21)
Amended by:
Official Journal
No page date
►M1CommissionDirective 81/680/EEC of 30 July 1981 L 246 32 29.8.1981
►M2CommissionDirective 92/89/EEC of 3 November 1992 L 344 35 26.11.1992
►M3CommissionDirective 98/54/EC of 16 July 1998 L 208 49 24.7.1998
►M4CommissionDirective 1999/27/EC of 20 April 1999 L 118 36 6.5.1999
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FOURTHCOMMISSIONDIRECTIVE
of5December 1972
establishingCommunitymethodsofanalysisfortheofficialcontrol
offeedingstuffs
(73/46/EEC)
THE COMMISSION OF THE EUROPEAN COMMUNITIES,
Having regard to the Treaty establishing the European Economic
Community;
Having regard to the Council Directive of 20 July 1970(1) onthe in tro-
duction of Community methods of sampling and analysis for the
official control of feedingstuffs, as amended by the Directive No 72/275/EEC of 20 July 1972(
2), and in particular Article 2 thereof;
Whereas that Directive requires that official controls of feedingstuffs
be carried out using Community methods of sampling and analysis forthe purpose of checking compliance with requirements arising underthe provisions laid down by law, Regulation or administrative action
concerning the quality and composition of feedingstuffs;
Whereas Directives No 71/250/EEC of 15 June 1971(
3), No 71/393/
EEC of 18 November 1971(4) and No 72/199/EEC of 27 April
1972(5) have already established a number of Community methods of
analysis; whereas the progress of work since then makes it advisable toadopt a fourth set of methods;
Whereas the measures provided for inthis Directive are inaccordan ce
with the Opinion of the Management Committee for Feedingstuffs;
HAS ADOPTED THIS DIRECTIVE:
Article 1
The Member States shall require that analyses for official controls of
feedingstuffs as regards moisture contents of animal and vegetable
fats and oils and magnesium and crude fibre contents of feedingstuffsbe carried out according to the methods described in Annex I to thisDirective.
Article 3
The Member States shall, not later than 1 January 1974, bring into
force the laws, regulations or administrative provisions necessary tocomply with this Directive. They shall forthwith notify the Commissionthereof.
Article 4
This Directive is addressed to the Member States.1973L0046 — EN — 26.05.1999 — 004.001 — 2
(1) OJ No L 170, 3. 8. 1970, p. 2.
(2) OJ No L 171, 29. 7. 1972, p. 39.
(3) OJ No L 155, 12. 7. 1971, p. 13.
(4) OJ No L 279, 20. 12. 1971, p. 7.
(5) OJ No L 123, 29. 5. 1972, p. 6.▼M1
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ANNEX I
1.DETERMINATION OF MOISTURE IN ANIMAL AND VEGETABLE
FATSANDOILS
1.PurposeandScope
This method makes it possible to determine the water and volatile substances
content of animal and vegetable fats and oils.
2.Principle
The sample is dried to constant weight at 103 ºC. The loss in mass is deter-
mined by weighing.
3.Apparatus
3.1. Flat-bottomed dish, of a corrosion-resistant material, 8 to 9 cm in
diameter and approximately 3 cm high.
3.2. Mercury thermometer with a strengthened bulb and expansion tube at
the top end, graduated from approximately 80 ºC to at least 110 ºC,
and approximately 10 cm in length.
3.3. Sand bath or electric hot-plate.3.4. Desiccator, containing an efficient drying agent.
3.5. Analytical balance.
4.Procedure
Weigh out to the nearest mg approximately 20 g of the homogenized sample
into the dry, weighed dish (3.1) containing the thermometer (3.2). Heat on
the sand bath or hot-plate (3.3), stirring continuously with the thermometer,
so that the temperature reaches 90 ºC inabout 7 min utes.
Reduce the heat, watching the frequency with which bubbles rise from the
bottom of the dish. The temperature must not exceed 105 ºC. Continue to
stir, scraping the bottom of the dish, until bubbles stop forming.
In order to ensure complete elimination of moisture, reheat several times to
103 ºC ± 2 ºC, cooling to 93 ºC between successive heatings. Then leave to
cool to room temperature inthe desiccator (3.4) an d weigh. Repeat this
operation until the loss in mass between two successive weighings no longer
exceeds 2 mg.
N.B.An increase in the mass of the sample after repeated heating indicates
anoxidationof the fat, inwhich case calculate the result from the
weighing carried out immediately before the mass began to increase.
5.Calculationofresults
The moisture content, as a percentage of the sample, is given by the
following formula:
M
1/C0M2 ðÞ /C1100
Mo
where:
Mo= mass, ingrammes, of the test sample;
M1= mass, in grammes, of the dish with its contents before heating;
M2= mass, in grammes, of the dish with its contents after heating.
Results lower than0·05 % must be recorded as ‘lower than0·05 %’.
Repeatability
The difference in moisture between the results of two parallel determinations
carried out onthe same sample must n ot exceed 0·05 %, inabsolute value.1973L0046 — EN — 26.05.1999 — 004.001 — 3
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2.DETERMINATIONOFMAGNESIUM
— by atomic absorptionspectrophotometry —
1.PurposeandScope
This method makes it possible to determine the quantity of magnesium in
feeding stuffs. It is particularly appropriate for determining magnesium
contents lower than 5 %.
2.Principle
The sample is ashed and dissolved in dilute hydrochloric acid. If it contains
no organic substances, it is dissolved directly in dilute hydrochloric acid. The
solution is diluted and the magnesium content determined by atomic absorp-
tion spectrophotometry at 285·2 nm, by comparison with standard solutions.
3.Reagents
3.1. Hydrochloric acid a.p. d: 1·16.
3.2. Concentrated hydrochloric acid a.p. d: 1·19.3.3. Magnesium ribbon or wire, or magnesium sulphate heptahydrate, dried
at room temperature.
3.4. Strontium salt solution (chloride or nitrate) at 2·5 % (w/v) strontium
(= 76·08 g SrC1
2·6 H2O a.p., or 60·38 g Sr (NO3)2a.p.).
3.5. Standard magnesium solution: weigh out to the nearest mg 1 g magne-
sium (3.3) which has previously had its oxide coating carefully
removed, or the corresponding quantity (10·143 g) of magnesium
sulphate heptahydrate (3.3). Place ina 1 000 ml graduated flask, add
80 ml hydrochloric acid (3.1), leave to dissolve and make up to
1 000 ml with water. 1 ml of this solution contains 1·000 mg magne-
sium.
4.Apparatus
4.1. Platinum, silica or porcelain ashing crucibles.
4.2. Thermostatically controlled electric muffle furnace.
4.3. Atomic absorptionspectrophotometer.
5.Procedure
5.1.Preparation of the sample solution
5.1.1.Feeding stuffs composed exclusively of mineral substances
Weigh out to the nearest mg 5 g of the sample into a 500 ml
graduated flask with 250 to 300 ml water. Add 40 ml hydro-
chloric acid (3.1), bring to the boil and keep the liquid gently
boiling for 30 minutes. Leave to cool, make up to volume with
water, mix and filter into a dry beaker through a dry pleated
filter. Discard the first 30 ml of the filtrate. Inthe presen ce of
silica, treat 5 g of sample with a sufficient quantity (15—30 ml)
of hydrochloric acid (3.2), evaporate to dryness on a water bath
and transfer to an oven at 105 ºC for one hour. Proceed as from
the third sentence of 5.1.2.
5.1.2.Feeding stuffs composed predominantly of mineral substances
Weigh out to the nearest mg 5 g of the sample into a crucible and
ash at 550 ºC in the muffle furnace until an ash which is free
from carbonaceous particles is obtained, and leave to cool. In
order to eliminate silica, add to the ash a sufficient quantity
(15—30 ml) of hydrochloric acid (3.2), evaporate to dryness on
a water bath and transfer to an oven at 105 ºC for one hour. Treat
the residue with 10 ml hydrochloric acid (3.1) and transfer to a
500 ml graduated flask using warm water. Leave to cool and
make to volume with water. Mix and filter into a dry beaker
through a dry pleated filter. Discard the first 30 ml of the filtrate.
5.1.3.Feedingstuffs composed predominantly of organic substances
Weigh out to the nearest mg 5 g of the sample into a crucible and
ash at 550 ºC in the muffle furnace until an ash which is free
from carbonaceous particles is obtained. Treat the ash with 5 ml
hydrochloric acid (3.2), evaporate to dryness on a water bath and
then dry for one hour in the oven at 105 ºC in order to render the1973L0046 — EN — 26.05.1999 — 004.001 — 4
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silica insoluble. Treat the ash with 5 ml hydrochloric acid (3.1),
transfer to a 250 ml graduated flask using warm water, bring to
the boil, leave to cool and make up to volume with water. Mix
and filter into a dry beaker through a dry pleated filter. Discard
the first 30 ml of the filtrate.
5.2.Measurement by atomic absorption
By diluting the standard solution (3.5) with water, prepare at least 5
reference solutions of increasing concentration, corresponding to the
optimal measuring range of the spectrophotometer. Add to each solution
10 ml strontium salt solution (3.4) and then make up the volume to
100 ml with water. Dilute with water one aliquot part of the filtrate
obtained from 5.1.1, 5.1.2 or 5.1.3, so as to obtain a magnesium concen-
tration which is within the limits of concentration of the reference
solutions. The hydrochloric acid concentration of this solution must not
exceed 0·4 N. Add 10 ml strontium salt solution (3.4) and then make up
the volume to 100 ml with water. Measure the absorptionof the solution
to be determined and of the reference solutions at 285·2 nm.
6.Calculationofresults
Calculate the quantity of magnesium in the sample by relation to the refer-
ence solutions. Express the result as a percentage of the sample.
Repeatability
The difference between the results of two parallel determinations carried out
onthe same sample must n ot exceed 5 %, inrelative value.
3.DETERMINATIONOFCRUDEFIBRE
1.Purposeandscope
This method makes it possible to determine fat-free organic substances in
feedingstuffs which are insoluble in acid and alkaline media and are conven-
tionally described as crude fibre.
2.Principle
The sample, defatted where necessary, is treated successively with boiling
solutions of sulphuric acid and potassium hydroxide of specified concentra-
tions. The residue is separated by filtration on a sintered-glass filter washed,dried, weighed and ashed within a range of 475 to 500 ºC. The loss of weight
resulting from ashing corresponds to the crude fibre present in the test
sample.
3.Reagents
3.1. Sulphuric acid, c = 0,13 mol/l.
3.2. Anti-foaming agent (e.g. n-octanol).
3.3. Filter aid (Celite 545 or equivalent), heated at 500 ºC for four hours
(8.6).
3.4. Acetone.
3.5. Light petroleum boiling-range 40 to 60 ºC.
3.6. Hydrochloric acid, c = 0,5 mol/l.
3.7. Potassium hydroxide solution, c = 0,23 mol/l.
4.Apparatus
4.1. Heating unit for digestion with sulphuric acid or potassium hydroxide
solution, equipped with a support for the filter crucible (4.2) and
provided with anoutlet tube with a tap to the liquid outlet an d vacuum,
possibly with compressed air. Before use each day preheat the unit with
boiling water for five minutes.
4.2. Glass filter crucible with fused sintered glass filter plate pore size 40-
90 µm. Before first use, heat to 500 ºC for a few minutes and cool (8.6).
4.3. Cylinder of at least 270 ml with a reflux condenser, suitable for boiling.
4.4. Drying oven with thermostat.
4.5. Muffle furnace with thermostat.1973L0046 — EN — 26.05.1999 — 004.001 — 5
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4.6. Extraction unit consisting of a support plate for the filter crucible (4.2.)
and with a discharge pipe with a tap to the vacuum and liquid outlet.
4.7. Connecting rings to assemble the heating unit (4.1), crucible (4.2) and
cylinder (4.3) and to connect the cold extraction unit (4.6) and crucible.
5. Procedure
Weigh out to the nearest 0,001 g, 1 g of the prepared sample and place it in
the crucible (4.2), (see observations 8.1, 8.2 and 8.3) and add 1 g of filter aid
(3.3).
Assemble the heating unit (4.1) and the filter crucible (4.2), then attach the
cylinder (4.3) to the crucible. Pour 150 ml of boiling sulphuric acid (3.1) into
the assembled cylinder and crucible and if necessary add a few drops of anti-
foaming agent (3.2).
Bring the liquid to the boil within 5 ± 2 minutes and boil vigorously for
exactly 30 minutes.
Open the tap to the discharge pipe (4.1) and, under vacuum, filter the
sulphuric acid through the filter crucible and wash the residue with three
consecutive 30 ml portions of boiling water, ensuring that the residue is
filtered dry after each washing.
Close the outlet tap and pour 150 ml boiling potassium hydroxide solution
(3.7) to the assembled cylinder and crucible and add a few drops of anti-
foaming agent (3.2). Bring the liquid to boiling point within 5 ± 2 minutes
and boil vigorously for exactly 30 minutes. Filter and repeat the washing
procedure used for the sulphuric acid step.
After the final washing and drying, disconnect the crucible and its contents
and reconnect it to the cold extraction unit (4.6). Apply the vacuum and
wash the residue in the crucible with three consecutive 25 ml portions of
acetone (3.4) ensuring that the residue is filtered dry after each washing.
Dry the crucible to constant weight in the oven at 130 ºC. After each drying
cool inthe desiccator an d weigh rapidly. Place the crucible ina muffle
furnace and ash to constant weight at 475 ºC to 500 ºC for at least 30
minutes.
After each heating cool first in the furnace and then in the desiccator before
weighing.
Carry out a blank test without the sample. Loss of weight resulting from
ashing must not exceed 4 mg.
6.Calculationofresults
The crude fibre content as a percentage of the sample is given by the expres-
sion:
b/C0c ðÞ /C2 100
a
where
a = mass of sample ing;
b = loss of mass after ashing during the determination, in g;c = loss of mass after ashing during the blank test, in g.
7.Repeatability
The difference between two parallel determinations carried out on the same
sample must not exceed:
— 0,3 in absolute value for crude fibre contents lower than 10 %,
— 3 % relative to the higher result, for crude fibre contents equal to or
greater than10 %.
8.Observations
8.1. Feedingstuffs containing more than 10 % crude fat must be defatted
prior to analysis with light petroleum (3.5). Connect the filter crucible
(4.2) and its contents to the cold extraction unit (4.6) and apply vacuum
and wash the residue with three consecutive 30 ml portions of light
petroleum, ensuring that the residue is dry. Connect the crucible and its
contents to the heating unit (4.1) and continue as described under 5.1973L0046 — EN — 26.05.1999 — 004.001 — 6
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8.2. Feedingstuffs containing fats which cannot be extracted directly with
light petroleum (3.5) must be defatted as shownin8.1 an d defatted
once more after boiling with acid.
After boiling with acid and the subsequent washing connect the crucible
and its contents to the cold extraction unit (4.6) and wash three times
with 30 ml acetone followed by three further washings with 30 ml
portions of light petroleum. Filter under vacuum until dry and continue
the analysis as described under 5, beginning with potassium hydroxide
treatment.
8.3. If the feedingstuffs contain over 5 % of carbonates, expressed as
calcium carbonate, connect the crucible (4.2) with the weighed sample
to the heating unit (4.1). Wash the sample three times with 30 ml hydro-
chloric acid (3.6). After each addition let the sample stand for about one
minute before filtering. Wash once with 30 ml water and then continue
as described under 5.
8.4. If anapparatus inthe form of a stan d is used (several crucibles attached
to the same heating unit) no two individual determinations on the same
sample for analysis may be carried out in the same series.
8.5. If after boiling it is difficult to filter the acidic and basic solutions, use
compressed air through the discharge pipe of the heating unit and then
continue filtering.
8.6. The temperature for ashing should not be higher than 500 ºC in order to
extend the lifetime of the glass filter crucibles. Care must be taken to
avoid excessive thermal shock during heating and cooling cycles.1973L0046 — EN — 26.05.1999 — 004.001 — 7
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