Ministry of Agricultural, Food and Forestry Policies
CENTRAL INSPECTORATE DIVISION FOR THE PROTECTION OF QUALITY AND THE
REPRESSION OF FRAUD IN AGRO-FOOD PRODUCTS
DIRECTORATE GENERAL FOR THE PREVENTION AND FOR THE FIGHT AGAINST
FRAUD CONCERNING AGRO-FOOD PRODUCTS
1. ------IND- 2016 0021 I-- EN- ------ 20160127 --- --- PROJET
Decree No _______
Approval of the official methods for analysing fertilisers - Supplement No 13
DIRECTOR-GENERAL
HAVING REGARD TO Legislative Decree No 282 of 18 June 1986, converted, with
amendments, into Law No 462 of 7 August 1986, Article 10 of which provided for the establishment
of the Central Inspectorate for the Repression of Fraud within the Ministry of Agriculture and
Forestry for the performance, among other things, of duties inherent to the prevention and repression
of violations in the preparation and trade of agro-food products and substances for agrarian and
forestry use;
HAVING REGARD TO Legislative Decree No 165 of 30 March 2001 and subsequent
amendments;
HAVING REGARD TO Ministerial Decree of 5 May 2006 of the pro tempore Ministry of
Agricultural and Forestry Policies concerning the establishment, in accordance with Article 44 of
Law No 82 of 20 February 2006, of the Consultative Commission for the update of the official
analysis method of agro-food products and substances for agrarian and forestry use, structured into
10 sub-commissions with sector-specific competencies, including the Sub-commission for fertilisers
and related products, established and appointed by Ministerial Decree No 1793 of 19 December 2008
as subsequently amended in its composition;
HAVING
4 August 2010 in
the reduction of
extension of the
28 June 2012;
REGARD TO the Directive of the President of the Council of Ministers of
relation to interpretative guidelines on the reorganisation of collective bodies and
the costs of the administrative apparatus that ordered the operation, under an
above-mentioned Consultative Commission and related sub-commissions until
HAVING REGARD TO Article 6 of Legislative Decree No 75 of 29 April 2010 on the
and revision of the regulations governing fertilisers, pursuant to Article 13 of Law
No 88 of 7 July 2009,” which provides that compliance with the provisions regarding conformity
with respect to the types of fertilisers and compliance of the declared titres of fertilising elements or
declared titres of the forms and solubility of said elements shall be ascertained, during official
inspections, by means of the sampling and analysis methods adopted by a decree of the Ministry of
Agricultural, Food and Forestry Policies after seeking the opinion of the Consultative Commission
pursuant to Article 44 of Law No 82 of 20 February 2006;
“Reorganisation
HAVING REGARD TO Decree of the President of the Council of Ministers No 105 of
27 February 2013 laying down the “Organisation of the Ministry of Agricultural, Food and Forestry
Policies,” Article 4 of which establishes for the Central Inspectorate the title “Dipartimento
dell’Ispettorato centrale della tutela della qualità e repressione frodi dei prodotti agro-alimentari”
Ministry of Agricultural, Food and Forestry Policies
CENTRAL INSPECTORATE DIVISION FOR THE PROTECTION OF QUALITY AND THE
REPRESSION OF FRAUD IN AGRO-FOOD PRODUCTS
DIRECTORATE GENERAL FOR THE PREVENTION AND FOR THE FIGHT AGAINST
FRAUD CONCERNING AGRO-FOOD PRODUCTS
(Central Inspectorate Division for the Protection of Quality and the Repression of Fraud in AgroFood Products) with the acronym ICQRF, confirming among its responsibilities the updating of
official methods of analysis of agro-food products and substances for agrarian and forestry use;
HAVING REGARD TO the Ministerial Decree of 24 March 1986 regarding the approval of
the “Official methods for analysing fertilisers,” published in the Ordinary Supplement of the Official
Journal of the Italian Republic No 180 of 5 August 1986, most recently amended and supplemented
by Decree No 1377 of 27 January 2014, Supplement No 12, published on the institutional website of
the Ministry of Agricultural, Food and Forestry Policies;
HAVING CONSIDERED it necessary to incorporate the compilation of analysis methods into
the analytical methods suitable for checking national fertilisers already incorporated or pending
incorporation in the annexes of Legislative Decree No 75 of 29 April 2010, as amended and
expanded;
CONSIDERING that the methods assessed for the “Determination of the isotopic ratio of
sulfur (34S/32S)”, the “Determination of the total carbon content of organic origin and total hydrogen”
and the “NMR analysis of industrial and urban sludge” are suitable for application in terms of
precision and accuracy, in compliance with the guidelines for the preparation of the test methods
approved by the Consultative Commission pursuant to Article 44 of Law No 82 of 20 February 2006;
HAVING REGARD TO Directive (EU) No 2015/1535 laying down a procedure for the
provision of information in the field of technical regulations and of rules on Information Society
services (codification);
HEREBY DECREES
Article 1
1. The official analysis methods for fertilisers are approved, Supplement No 13, described in an
annex to this Decree.
2. The methods of analysis described in the annex to this Decree apply to the inspection of national
fertilisers.
Article 2
This Decree shall enter into force the day after its publication on the institutional website of the
Ministry of Agricultural, Food and Forestry Policies.
p. THE MINISTRY OF AGRICULTURAL, FOOD AND FORESTRY POLICIES
The Director-General of the Directorate-General for the Prevention and for the Fight Against
Fraud Concerning Agro-Food Products
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Ministry of Agricultural, Food and Forestry Policies
CENTRAL INSPECTORATE DIVISION FOR THE PROTECTION OF QUALITY AND THE
REPRESSION OF FRAUD IN AGRO-FOOD PRODUCTS
DIRECTORATE GENERAL FOR THE PREVENTION AND FOR THE FIGHT AGAINST
FRAUD CONCERNING AGRO-FOOD PRODUCTS
Rome, on
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Ministry of Agricultural, Food and Forestry Policies
CENTRAL INSPECTORATE DIVISION FOR THE PROTECTION OF QUALITY AND THE
REPRESSION OF FRAUD IN AGRO-FOOD PRODUCTS
DIRECTORATE GENERAL FOR THE PREVENTION AND FOR THE FIGHT AGAINST
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ANNEX
OFFICIAL METHODS FOR ANALYSING FERTILISERS
Supplement No 13
1. Determination of the isotopic ratio of sulfur (34S/32S)
2. Determination of the total carbon content of organic origin and total hydrogen content
3. NMR analysis of industrial and urban sludge. Urban sludge, after clarification, preceded by a
potential treatment with oxygenated water
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Ministry of Agricultural, Food and Forestry Policies
CENTRAL INSPECTORATE DIVISION FOR THE PROTECTION OF QUALITY AND THE
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1.
Determination of the isotopic ratio of sulfur (34S/32S)
WARNING: the people appointed to carry out this test method must be familiar with normal
laboratory practice; this method does not deal with the safety problems associated with its
application, if such should exist. The user is responsible for establishing good practices for safety and
health and to guarantee conformity with Italian legislation.
1. Subject
This document describes a method for determining the isotopic ratio of sulfur (34S/32S) in fertilisers
and/or matrices for which this ratio is useful to their characterisation and traceability.
2. Scope
This method can apply to all solid and liquid fertilisers.
3. Terms and definitions
34
S/32S: isotopic ratio of sulfur 34 and sulfur 32 for a given sample. This value is also defined as R.
δ34S: 34S content expressed in parts per 1 000 (‰) with respect to the international primary reference
material.
V-CDT: Vienna-Canyon Diablo Troilite (CDT) is the universal reference standard for the
measurement of the isotopic ratio of sulfur, and all measurements are expressed in reference to this
standard. As regards sulfur, this standard is an iron sulfur mineral (troilite) obtained from the
meteorite Canyon Diablo, which includes numerous fragments of an asteroid that struck Earth at the
Barringer Crater (Meteor Crater), in Arizona, USA. Reference materials calibrated to universal
standards are available from the International Atomic Energy Agency (IAEA) in Vienna, Austria.
4. Principle
An element’s isotopes have small differences in their physical and chemical properties caused by
their different mass. For elements with a low atomic number, these differences in mass are
sufficiently large as to mean that thermodynamic reactions or biological processes can lead to
isotopic splitting, i.e. they can change the relative proportion of the different isotopes of the same
element in the various compounds (reagents and products of the reaction). Isotopic splitting can take
place in systems at equilibrium (“equilibrium effects”) and consist of an exchange of isotopes of each
of the two molecular species or phases that take part in a reaction. The reaction can be a simple
change in state or chemical transformation. Isotopic splits also take place following incomplete, oneway processes, such as evaporation, reactions of dissociation, dissemination and biochemical
reactions. This type of one-way reaction (“non-equilibrium effect”) generally results in preferential
enrichment in a light isotope in reaction products. More specifically, through their metabolic
activities, live organisms always produce one-way isotopic splits (“non-equilibrium effects”). Isotopic
splitting due to metabolic activities can also be the result of both types of splitting due to systems in
equilibrium and one-way reactions. The isotopic composition of a substance is therefore the result of
the isotopic composition of the original material and the physical, chemical and biochemical
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transformations it undergoes over time. The
following complete sample combustion.
34
S content is measured in the SO2 gas that forms
The comparison with the laboratory standard calibrated according to the universal reference
standards makes it possible to calculate and express the content of 34S of a sample in terms of δ unit
(‰).
5. Reactions and interference
The method is based on the use of an elemental analysis technique coupled with mass spectroscopy;
no reactions are used for analysis, and no interference is envisaged.
6. Reagents
The materials and consumables depend on the equipment used by the laboratory. The systems used
for the combustion of the sample are generally based on elemental analysers. These systems can be
prepared for the introduction of samples positioned in sealed metal capsules or for the injection of
liquid samples. Depending on the type of instruments used, the following reference materials,
reagents and consumables can be used:
6.1 Reference materials available at the IAEA (by way of example):
Name
Material
δ 34S with respect to V-CDT
IAEA S-1
Silver sulfide
-0.30 ‰
IAEA S-2
Silver sulfide
+22.7 ‰
IAEA S-3
Silver sulfide
-32.3 ‰
IAEA S-4
Sulfur
+16.9 ‰
IAEA SO-5
Barium sulfate
+0.5 ‰
6.2 Working standard
6.2.1 Sulfur dioxide (SO2) of a suitable purity, as a secondary reference gas for the measurement of
δ34S.
6.2.2 Working standard and standard for internal inspections with a reference value of δ 34S calibrated
with respect to the international reference materials (e.g. casein).
6.3 Consumable materials
Below is an approximate list of consumables for continuous flow systems.
6.3.1 Copper oxide (CuO) for microanalysis, granular.
6.3.2 Reduced copper (Cu) for microanalysis, in coils or wire.
6.3.3 Chrome oxide (III) for microanalysis, granular.
6.3.4 Magnesium perchlorate (Mg(ClO4)2) for microanalysis, granular.
6.3.5 Gaseous oxygen (O2) with a minimum purity of 99.995 %.
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6.3.6 Gaseous helium (He) with a minimum purity of 99.999%.
6.3.7 Disposable tin capsules, with dimension 5 (i.d.) x 8 (h) mm or similar.
6.3.8 Quartz wool.
6.3.9 Chromosorb (inert absorbent material for determination of fluid samples).
6.3.10 Spoon-shaped spatula.
6.3.11 Tweezers.
6.3.12 Pasteur pipette.
NB: the laboratory can use different materials and/or reagents, depending on its instruments, as long
as the minimum performance required by this method is guaranteed.
7. Equipment
7.1 Mass spectrometer for determining the isotopic ratios (IRMS).
The isotope ratio mass spectrometer enables the determination of the relative contents of 34S of SO2,
with an internal accuracy, expressed as the standard deviation from 10 measurements of the same
sample of standard gas, of no more than 0.08‰.
The instrument must be fitted with a continuous flow system that transfers the SO2 from the
combustion of the samples and working standards into the mass spectrometer.
7.2 Elemental analyser
Through dry combustion in the presence of oxygen, the elemental analyser enables the quantitative
conversion of the sulfur of the sample into SO2, the elimination of other products of combustion,
including water, and the separation of the gases that form.
In turn, the analyser can be configured with a self-sampler for solids or liquids, the first is in any case
to be preferred insofar as it enables the analysis of both sample types: solid and liquid.
7.3 Precision scales with a minimum format unit of 10 μg.
8. Preparation of the sample
8.1 Preparation of the solid sample
Weigh an aliquot of air-dried, finely ground (< 250 m) sample on the precision scales (7.3), in
the tin capsules (6.3.7). Use the tweezers to close the capsule (6.3.11), being careful not to break it
or touch it by hand. Weigh it when the capsule is closed.
8.2 Preparation of the fluid sample
Put a little Chromosorb (6.3.9) into the tin capsule, so as to have a layer of inert material in the
bottom of the capsule. Calibrate the capsule with Chromosorb. With the Pasteur pipette or similar,
put a small aliquot of fluid sample into the capsule. Use the tweezers to close the capsule (6.3.11),
being careful not to break it, and use laboratory gloves to avoid leaving any residues on the
surface.
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NB: The quantity of sample to be weighed generally varies from a few hundred micrograms to a few
milligrams, depending on the assumed S content of the sample. It may be useful for this purpose to
perform some preliminary analyses to determine the optimal quantity of sample to be weighed, so as
to ensure that the SO2 signal in the spectrometer is as similar as possible to that of the reference
standard.
The sample can be injected with syringes, potentially using a self-sampler for liquids, in respect of
the above criteria.
8.3 Cleaning work tools
Wash the tweezers and spatula thoroughly between one sample and the next, using distilled water and
ethanol.
8.4 Blank preparation
The blank consists of an empty capsule.
8.5 Preparation of the standard
Weigh out a suitable number of capsules on the precision scales, containing the working standard and
internal control (6.2.2), so as to have a quantity of S of the standard such as to provide a signal that is
as similar as possible to that of the sample.
9. Procedure
9.1 Instrument checks
- For optimal sample combustion, regulate the furnace temperature of the elemental analyser and the
flows of gaseous helium and oxygen.
- Start an analysis sequence of at least 10 samples of the working standard.
The standard deviation must be less than 0.15‰;
- Also check the efficacy of the analyser combustion flash by analysing an empty capsule;
- Before starting to measure the samples, check the system using working and internal control
materials (6.2.2).
9.2 Sequence preparation
The analysis procedure is managed by software. The sequence of samples to be analysed is set on the
isotope ratio mass spectrometer management software according to the criterion that establishes, in
order, an initial blank, at least two standards, the samples and at least two more standards at the end
of the sequence. At least three replications of each sample are analysed.
10 Expression of results
The value of isotopic ratios, calculated by the software and potentially corrected as shown below, is
expressed as delta unit per thousand (δ ‰):
δ 34S ‰ = [(Rsample /Rstandard) – 1] x 1000
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Rsample and Rstandard is the isotopic ratio 34S/32S, respectively, of the sample and standard. The
universal reference standard for S is the Vienna-Canyon Diablo Troilite (V-CDT).
In the calculations, the raw values of δ are used with three decimal figures supplied by the
instrument, while the final result is expressed as a decimal figure.
11 Precision
11.1 Repeatability
The repeatability of the measurements, expressed as the absolute difference between the two
individual results of the same test material by an operator using the same equipment in the shortest
time frame possible, must be no greater than the value of r. The value r for δ 34S = 19.33 is r = 0.5 ‰.
NB: the laboratory considers the values of repeatability, in assessing the precision obtained, for each
sample, following the repetition of the three replications. The comparison can be drawn using
Fisher’s F-test or another equivalent statistical test.
11.2 Accuracy of the measurement
Considering that, when measuring in line, there may be minor differences due to the variation of
instrument conditions, the laboratory implements suitable analysis procedures by which to ensure the
accuracy of the measurement and the reference to the international reference standard, including
through the use of internal working standards and controls.
NB: By way of example, the following procedure is given. The experimental values of δ34S of the
samples must be corrected according to the difference between the working standard value and its
real value, previously calibrated with respect to the V-CDT for comparison with one of the
international reference materials. In this case, the correction to be made to the samples varies in a
linear fashion with respect to the difference in the value of the two previous working standards and
follow the samples. The working reference needs to be measured at the start and end of each series of
samples. A correction can then be calculated for each sample by means of linear interpolation
between the two values (the difference between the value assigned to the working standard and the
measurements of values obtained).
12. Bibliography
 Robinson, B. W. (1995): Sulphur isotope standards. Proceedings of a consultants' meeting held
in Vienna, 1-3 December 1993 IAEA-TECDOC-825, 39-45.
 Stichler, W., Gonfiantini, R., Rozanski, K. (1995): Reference and intercomparison materials for
stable isotopes of light elements. Proceedings of a consultants' meeting held in Vienna, 1-3
December 1993. IAEA-TECDOC-825, 7-11.
 Coplen, T. B., Krouse, H. R. (1998): Sulphur isotope data consistency improved. Nature, 392,
32.
 Fritz, P., Drimmie, R.J., and Nowicki, V.K. (1974). Preparation of sulfur dioxide for mass
spectrometer analyses by combustion of sulfides with copper oxide. Anal. Chem., 46, 164-6.
 Haur, A., Hladikova, J., and Smejkal, V. (1973). Procedure of direct conversion of sulfates into
S02 for mass spectrometric analysis of sulfur. Isotopenpraxis, 9, 329-31.
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

Robinson, B.S., and Kusakabe, M. (1975). Quantitative preparation of sulfur dioxide, for 34Sp2S
analyses, from sulfides by combustion with cuprous oxide. Anal. Chem., 47, 1179-81.
Ueda, A., and Krouse, H.R. (1987). Direct conversion of sulphide and sulphate minerals to S02
for isotope analyses. Geochem. J., 20, 209-12.
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2.
Determination of total carbon content of organic origin and total hydrogen
WARNING: The people appointed to carry out this test method must be familiar with normal
laboratory practice. This method does not deal with the safety problems associated with its use, if
such should exist. The user is responsible for establishing good practices for safety and health and to
guarantee conformity with Italian legislation.
1. Introduction
This test method is specific for the determination of carbon and hydrogen in the biochar.
2. Subject
This document proposes a method for determining the carbon and hydrogen in the biochar, classified
as a soil improver and component of growing media. The method proposed, dry combustion, was
developed as the Dumas manual method. Its application has been considerably improved through the
use of automated instruments.
3. Scope
This test method applies only to the biochar matrix obtained from pyrolysis and gasification, to be
used as a soil improver and/or component of growing media.
The limits of detection and field of measurement refer to and are traced to the type of instrument
used. The range of measurement is between 0.2 % and 95 % of C and between 0.1 % and 13 % of H.
4. Regulatory framework
UNI EN 13040:2008, Soil improvers and growing media. Sample preparation for chemical and
physical tests, determination of dry matter content, moisture content and laboratory compacted bulk
density.
UNI EN 12579:2002, Soil improvers and growing media. Sampling.
5. Terms and definitions
The terms and definitions used in this method are those pursuant to the reference standard
UNI EN 13040:2008.
6. Principle
The method is based on the complete and instant oxidation of the sample by “flash combustion.”
The sample is heated to at least 900°C in the presence of oxygen; the compounds deriving from the
combustion (CO2, N2, H2O and SO2) are detected using a thermal conductivity detector.
7. Reactions and interference
Following the complete, instant oxidation of the sample by flash combustion, all organic and
inorganic substances are converted into gaseous products. The combustion gases pass, in a helium
current, onto a layer of a suitable catalyst, to complete the oxidation process and then onto a layer of
copper to remove any excess oxygen. Thereafter, the gaseous mixture is separated by gas
chromatography; CO2 and H2O (in addition to N2, and SO2) are detected by a thermal conductivity or
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IR absorption detector. Calcium carbonate (inorganic carbon), which is potentially present in the
sample, can be preventively removed by means of treatment with HCl or removed later, following
volumetric gas determination and stoichiometric calculation of inorganic C.
8. Reagents
Only use reagents with a recognised analytical quality.
Reference material of known titre; by way of example acetanilide (C8H9NO) (CAS No 103-84-4),
atropine (C17H23NO3) (CAS No 51-55-8), cyclohexanone 2-4 DNPH (C12H14N4O4) (CAS No 158962-4).
The reference materials must have a concentration of the element sought that is as close as possible to
that present in the matrix to be analysed.
9. Equipment and consumable materials
Normal laboratory equipment, in particular:
9.1 Analytical scales that are capable of weighing with a precision of 1.0 mg.
9.2 Elemental analyser CHN or CHNS (Dumas equipment) used to determine the carbon and
hydrogen content of the sample combustion at a temperature of at least 900°C, including detectors
used to determine the quantity of carbon and hydrogen present.
9.3 Disposable tin (or silver) capsules, of a suitable size for the instrument to be used (refer to the
user’s manual of the instrument provided)
10. Sampling
UNI EN 12579:2002, Soil improvers and growing media. Sampling.
11. Procedure
11.1 Preparation of test aliquots
Weigh out an aliquot of sample dried at 75°C in a tin capsule (9.3) with an approximation of 0.1 mg,
as indicated in standard UNI EN 13040:2008 (paragraph 9) and subsequently ground to 0.5 mm, in
relation to the concentration of the element envisaged in the sample.
At the same time, determine the residual humidity of the sample at 105°C on a second aliquot of
sample dried at 75°C, as indicated in standard UNI EN 13040:2008, in order to be able to express the
final datum on the dry matter.
11.2 Measurement system calibration
Calibrate the instrument as described in the manufacturer’s manual. For the purpose of calibration,
use one of the substances indicated under paragraph 8 or, in any case, a reference material with
known titre of the element to be determined. Again in accordance with the indication given in the
manufacturer’s manual, perform a calibration line with at least three concentration points of the
element to be determined, ensuring that the reading of the sample yields a datum that ranges between
the two extremes of the calibration line performed.
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11.3 Determination
Once closed, the tin capsules are placed inside the instrument samples, thereafter proceeding in
accordance with the indications and working instructions of the instrument supplied by the
manufacturer.
12. Expression of results
The total carbon and hydrogen content, expressed as a percentage of dry matter, is calculated
according to the following formulas:
Total carbon:
Ctot =
C1 1
´
M 1 10
where:
Ctot = % total carbon of dry matter.
l = mg total carbon present in the aliquot of the sample analysed.
M1 = g dry matter of the sample analysed, calculated as follows:
M1 = grams of the dry sample at 75°C ×
[100 – residual humidity %]
100
10 = coefficient to express the final datum as a percentage (%).
The analytical result is expressed with one decimal figure.
To express the total organic-origin carbon content in the sample, if the inorganic carbon has not been
removed in advance, subtract the value of inorganic carbon (determined separately using the gasvolumetric method) from the total carbon value.
NB
Description of volumetric gas method with calcimeter for determining inorganic carbon
in the biochar.
A sample containing carbonates (inorganic carbon) brought into contact with an acid
solution produces CO2.
The calcimeter (available on the market in various models) is an instrument with a
simple function that can quantify the volume of CO2 produced by a sample by reading
the variation in the water level contained in the instrument’s graduated tube. The
quantity of CO2 produced is expressed as CaCO3.
An aliquot of sample (ranging between 0.25 and 1.0 gram), prepared in accordance
with standard UNI EN 13040:2008 (paragraph 9, dried at 75°C), is placed in a flask in
which there is a second container holding 10 ml of a solution of HCl 1:1 v/v; once
connected to the calcimeter, the flask is inclined and manually shaken so as to bring the
acid solution into contact with the sample and facilitate the production of gas (CO2).
The quantity of gas produced is quantified by detecting the variation in the water level it
contains (in ml) in the graduated tube. Every five minutes, if the water level in the
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graduated tube has changed, gently shake the flask containing the sample with the acid
solution. When the water level in the graduated tube has not changed for at least one
hour, detect the total variation in the water level in the graduated tube, equivalent to the
ml of CO2 produced by the sample. In the meantime, carry out a blank test (same
operating conditions, without the sample). Before measuring the sample, the instrument
is calibrated using a standard of CaCO3 100 % (the instrument is calibrated for at least
two different concentrations of CaCO3 100 %).
The CO2 produced by the sample, expressed as a percentage of CaCO3, is calculated
using the following formula:
where:
CaCO3: % calcium carbonate present in the sample analysed (express the datum with
one decimal figure)
100 = conversion factor to express the datum as a %
m1 = sample weight in grams
12 = average weight in grams of the two concentrations of the standard used for
calibration
V1 = volume in ml of the CO2 produced by the sample
V2 = average volume in ml of the CO2 produced by the two concentrations of the
standard used for calibration
V3 = volume in ml of the CO2 produced by the blank test
In order to report the datum on the dry matter, use the datum of residual humidity
determined on a separate aliquot of sample, according to UNI EN 13040:2008.
Total carbon of organic origin is calculated using the following formula:
C org = C tot – C inorg
where:
C org = % total carbon of organic origin of dry matter.
C tot = % total carbon of dry matter.
C inorg = % inorganic carbon of dry matter obtained using the following formula.
C inorg = CaCO3 x 0.12.
where:
CaCO3 = % CaCO3 of dry matter.
0.12 = conversion factor to obtain the C content in the CaCO3.
Total hydrogen:
H tot =
H1 1
´
M 1 10
where:
H tot = % total hydrogen of dry matter.
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Ministry of Agricultural, Food and Forestry Policies
CENTRAL INSPECTORATE DIVISION FOR THE PROTECTION OF QUALITY AND THE
REPRESSION OF FRAUD IN AGRO-FOOD PRODUCTS
DIRECTORATE GENERAL FOR THE PREVENTION AND FOR THE FIGHT AGAINST
FRAUD CONCERNING AGRO-FOOD PRODUCTS
H1 = mg total hydrogen present in the aliquot of the sample analysed.
M1 = g dry matter of the sample analysed, calculated as follows:
M1 = grams of the dry sample at 75°C ×
[100 – residual humidity
%]
100
10 = coefficient to express the final datum as a percentage (%).
The analytical result is expressed with one decimal figure.
13. Precision
13.1 Strict repeatability (constant throughout whole range of measurement)
Repeatability limit (r) Carbon = 0.40 %
Repeatability limit (r) Hydrogen = 0.10 %
13.2 Reproducibility:
NB: The reproducibility limits indicated in the document are those reported in standard
DIN 51732:2007/2008 for the determination of carbon and hydrogen in carbon matrices (such as
biochar) and were obtained by means of the application of standard ISO 5725-1, with the
development of a proficiency test on 10 different samples of biochar, at different concentration levels
of the analytes to be sought, in which 11 laboratories took part.
Reproducibility limit (R) Carbon = 0.85 %
Reproducibility limit (R) Hydrogen = 0.40 %
14. Precision (recovery)
Carbon recovery index > 97 %
Hydrogen recovery index > 97 %
15. Limit of detection
Limit of detection: carbon = 0.07 % m/m
Limit of detection: hydrogen = 0.03 % m/m
16. Quantification limit
Carbon quantification limit: 0.2 % m/m
Hydrogen quantification limit: 0.1 % m/m
17. Bibliography
- Dumas J.B.A. 1831. Procedes de l’analyse organique. Ann. Chim. Phys. 247:198-213
- ISO 10694:1995. Soil Quality. Determination of organic and total carbon after dry combustion
(elementary analysis). International Organization for Standardization. Geneve, Switzerland.
- UNI EN 13654-02:2001 Soil improvers and growing media - Determination of nitrogen - Dumas
method
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Ministry of Agricultural, Food and Forestry Policies
CENTRAL INSPECTORATE DIVISION FOR THE PROTECTION OF QUALITY AND THE
REPRESSION OF FRAUD IN AGRO-FOOD PRODUCTS
DIRECTORATE GENERAL FOR THE PREVENTION AND FOR THE FIGHT AGAINST
FRAUD CONCERNING AGRO-FOOD PRODUCTS
- UNI EN 15104:2011 - Solid biofuels - Determination of total content of carbon, hydrogen and
nitrogen - Instrumental methods
- DIN 51732:2007-08 - Testing of solid mineral fuels - Determination of total carbon, hydrogen and
nitrogen - Instrumental methods
16
Ministry of Agricultural, Food and Forestry Policies
CENTRAL INSPECTORATE DIVISION FOR THE PROTECTION OF QUALITY AND THE
REPRESSION OF FRAUD IN AGRO-FOOD PRODUCTS
DIRECTORATE GENERAL FOR THE PREVENTION AND FOR THE FIGHT AGAINST
FRAUD CONCERNING AGRO-FOOD PRODUCTS
3.
NMR analysis of industrial and urban sludge. Urban sludge, after clarification, preceded
by a potential treatment with oxygenated water
WARNING: The people appointed to carry out this test method must be familiar with normal
laboratory practice. The description of the method does not deal with the safety problems associated
with its use, if such should exist. The user is responsible for establishing good practices for safety and
health and to guarantee conformity with Italian legislation.
1. Subject
This document determines a nuclear magnetic resonance (NMR) analysis method for sludge of
industrial and urban origin.
2. Scope and field of application
The method makes it possible to distinguish between sludge of urban and industrial origin, even
when in mixtures of the two. The method requires no chemical, physical or biological pre-treatment
of the sample, apart from drying the material in a heater before performing NMR analysis.
3. Principle of the method
The method does not envisage clarification of the sludge, which is therefore analysed as is, after
drying in a heater. At least 100 mg of sample is collected and transferred to a zirconium rotor with a
diameter of 7 mm for NMR analysis in solid state. The spectrum 13C-CPMAS-NMR (Cross
Polarization Magic Angle Spinning) is then recorded, rotating the sample at a speed of 7 kHz, and the
resulting spectrum, comprising 10 or so signals, is separated into the various contributions
(deconvolution). The analysis takes 12-18 hours.
4. Reactions and interferences
No interference, considering the lack of chemical handling required during preparation of the sample.
5. Equipment
5.1
5.2
Heater
NMR spectrometer with:
- 7 mm solid sample analysis probe;
- operating at a frequency of 1H 300 MHz or greater;
- with radio frequency channels for nuclei 1H and 13C;
- functioning at impulses and with Fourier transform of the NMR signal;
- system for optimising the frequency of 1H (tuning and matching);
- system for optimising the homogeneity of the field (shimming);
- channels for gradients along the z direction.
17
Ministry of Agricultural, Food and Forestry Policies
CENTRAL INSPECTORATE DIVISION FOR THE PROTECTION OF QUALITY AND THE
REPRESSION OF FRAUD IN AGRO-FOOD PRODUCTS
DIRECTORATE GENERAL FOR THE PREVENTION AND FOR THE FIGHT AGAINST
FRAUD CONCERNING AGRO-FOOD PRODUCTS
5.3
5.4
Analytical scales.
7 mm rotors for NMR analysis at solid state.
6. Procedure
6.1. Preparation of the sample
Dry the sample in a heater until a powder is obtained. Then pack the rotor for NMR at solid state
with a quantity of sample of at least 100 mg.
6.2 Measurement
Insert the rotor into the NMR spectrometer fitted with a probe for solid state analysis, then
optimise the homogeneity of the magnetic field B0 and the frequency of the nuclei 1H and 13C.
Then register the NMR spectrum using a sequence with transfer of polarisation from the nucleus
of the 1H to that of the 13C. The figure given below shows the general layout of the sequence.
ricevitore
receiver
140,800 scans are performed using a spectral window of 240.00 ppm centred at 110.00 ppm. The
spectrum acquired is multiplied by a pre-exponential factor of 5 Hz to reduce the noise and is then
transferred from the domain of time to that of frequency using the Fourier transform. The base and
phase line are then corrected. The spectrum is given by the sum of approximately 10 signals, each
corresponding to a specific functional group of the molecules present. The individual
contributions are calculated as a percentage of the total measuring the area below the signals: this
procedure is applied using a common deconvolution programme.
7. Calculation and expression of results
The analytical variations seen in a sludge of industrial origin with respect to one of urban origin can
be traced to two specific signals centred at 155.2 ppm and 196.3 ppm. These are entirely absent, or
have an intensity of less than 0.1 % in the case of a sludge of urban origin, and have an intensity
18
Ministry of Agricultural, Food and Forestry Policies
CENTRAL INSPECTORATE DIVISION FOR THE PROTECTION OF QUALITY AND THE
REPRESSION OF FRAUD IN AGRO-FOOD PRODUCTS
DIRECTORATE GENERAL FOR THE PREVENTION AND FOR THE FIGHT AGAINST
FRAUD CONCERNING AGRO-FOOD PRODUCTS
greater than 0.5 % in an industrial sludge. We therefore need merely to observe the presence of these
two signals to be certain of the type of sludge analysed.
8. Statistical parameters
For the statistical parameters of this method, please refer to Annex 1.
ANNEX 1
Statistical validation of the method
The repeatability values of the method obtained in the analysis of four industrial sludges obtained
from different locations.
The table below shows the results obtained for the signal at 155.2 ppm.
Parameter
Whole (%)
Sludge 1
1.78
Sludge 2
0.94
Sludge 3
1.01
Sludge 4
1.24
r (%)
0.03
0.01
0.04
0.01
The table below shows the results obtained for the signal at 196.3 ppm of sludge as is and treated.
Parameter
Sludge 1 as is
Whole (%)
2.49
Sludge 1
clarified
1.89
r (%)
0.04
0.07
19
1.47
Sludge 2
clarified
1.24
0.03
0.07
Sludge 2 as is
Ministry of Agricultural, Food and Forestry Policies
CENTRAL INSPECTORATE DIVISION FOR THE PROTECTION OF QUALITY AND THE
REPRESSION OF FRAUD IN AGRO-FOOD PRODUCTS
DIRECTORATE GENERAL FOR THE PREVENTION AND FOR THE FIGHT AGAINST
FRAUD CONCERNING AGRO-FOOD PRODUCTS
ANNEX 2
Analysis by means of 13C-CPMAS-NMR of (a) four industrial sludges of different composition, (b)
untreated urban-origin sludge, (c) urban sludge after clarification without or (d) with pre-treatment
with H2O2
a) Industrial sludge
20
Ministry of Agricultural, Food and Forestry Policies
CENTRAL INSPECTORATE DIVISION FOR THE PROTECTION OF QUALITY AND THE
REPRESSION OF FRAUD IN AGRO-FOOD PRODUCTS
DIRECTORATE GENERAL FOR THE PREVENTION AND FOR THE FIGHT AGAINST
FRAUD CONCERNING AGRO-FOOD PRODUCTS
b) Urban sludge as is
c) Urban sludge after clarification without pre-treatment with H2O2
21
Ministry of Agricultural, Food and Forestry Policies
CENTRAL INSPECTORATE DIVISION FOR THE PROTECTION OF QUALITY AND THE
REPRESSION OF FRAUD IN AGRO-FOOD PRODUCTS
DIRECTORATE GENERAL FOR THE PREVENTION AND FOR THE FIGHT AGAINST
FRAUD CONCERNING AGRO-FOOD PRODUCTS
d) Urban sludge after clarification after treatment with H2O2.
22