CEN/TS 15111:2005
(Main)Foodstuffs - Determination of trace elements - Determination of iodine in dietetic foods by ICP-MS (inductively coupled plasma mass spectrometry)
Foodstuffs - Determination of trace elements - Determination of iodine in dietetic foods by ICP-MS (inductively coupled plasma mass spectrometry)
This Technical Specification specifies a method for the determination of added inorganic iodine compounds, including water-soluble iodine compounds of natural origin, in dietetic foods by inductively coupled plasma mass spectrometry (ICP-MS).
Lebensmittel - Bestimmung von Elementspuren - Bestimmung von Iod in diätetischen Lebensmitteln mit der ICP-MS (Massenspektrometrie mit induktiv gekoppeltem Plasma)
Diese Technische Spezifikation legt ein Verfahren zur Bestimmung zugesetzter anorganischer Iodverbindun-gen
in diätetischen Lebensmitteln einschließlich wasserlöslicher Iodverbindungen natürlichen Ursprungs mit
der Massenspektrometrie und induktiv gekoppeltem Plasma (ICP-MS) fest.
Produits alimentaires - Dosage des éléments en traces - Dosage de l'iode dans les aliments diététiques par spectrométrie d'émission avec plasma induit par haute fréquence et spectromètre de masse (ICP-SM)
La présente Spécification technique spécifie une méthode de dosage par spectrométrie d'émission à plasma induit par haute fréquence avec spectromètre de masse (ICP-SM) des composés organiques iodés, y compris les composés iodés d'origine naturelle solubles dans l'eau, ajoutés dans les aliments diététiques.
Živila – Določevanje elementov v sledovih – Določevanje joda v dietetični hrani z ICP-MS (masno spektrometrijo z induktivno sklopljeno plazmo)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-december-2005
äLYLOD±'RORþHYDQMHHOHPHQWRYYVOHGRYLK±'RORþHYDQMHMRGDYGLHWHWLþQLKUDQL]
,&306 PDVQRVSHNWURPHWULMR]LQGXNWLYQRVNORSOMHQRSOD]PR
Foodstuffs - Determination of trace elements - Determination of iodine in dietetic foods
by ICP-MS (inductively coupled plasma mass spectrometry)
Lebensmittel - Bestimmung von Elementspuren - Bestimmung von Iod in diätetischen
Lebensmitteln mit der ICP-MS (Massenspektrometrie mit induktiv gekoppeltem Plasma)
Produits alimentaires - Dosage des éléments en traces - Dosage de l'iode dans les
aliments diététiques par spectrométrie d'émission avec plasma induit par haute
fréquence et spectrometre de masse (ICP-SM)
Ta slovenski standard je istoveten z: CEN/TS 15111:2005
ICS:
67.050 Splošne preskusne in General methods of tests and
analizne metode za živilske analysis for food products
proizvode
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
TECHNICAL SPECIFICATION
CEN/TS 15111
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
August 2005
ICS 01.140.20
English Version
Foodstuffs - Determination of trace elements - Determination of
iodine in dietetic foods by ICP-MS (inductively coupled plasma
mass spectrometry)
Produits alimentaires - Dosage des éléments en traces - Lebensmittel - Bestimmung von Elementspuren -
Dosage de l'iode dans les aliments diététiques par Bestimmung von Iod in diätetischen Lebensmitteln mit der
spectrométrie d'émission avec plasma induit par haute ICP-MS (Massenspektrometrie mit induktiv gekoppeltem
fréquence et spectromètre de masse (ICP-SM) Plasma)
This Technical Specification (CEN/TS) was approved by CEN on 26 March 2005 for provisional application.
The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit their
comments, particularly on the question whether the CEN/TS can be converted into a European Standard.
CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS available
promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS)
until the final decision about the possible conversion of the CEN/TS into an EN is reached.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 15111:2005: E
worldwide for CEN national Members.
Contents Page
Foreword .3
1 Scope .4
2 Normative references .4
3 Principle.4
4 Reagents.4
5 Apparatus and equipment.6
6 Sampling.7
7 Procedure .7
8 Evaluation.9
9 Limit of quantification.9
10 Precision.9
11 Test report .10
Annex A (informative) Results of the inter-laboratory test. .11
Bibliography.12
Tables
Table 1 — Mean values, repeatability and reproducibility. 10
Table A.1 — Statistical results of the inter-laboratory tests. 11
Table A.2 — Accuracy results. 11
Foreword
This Technical Specification (CEN/TS 15111:2005) has been prepared by Technical Committee CEN/TC 275
“Food analysis - Horizontal methods”, the secretariat of which is held by DIN.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to announce this Technical Specification: Austria, Belgium, Cyprus, Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland
and the United Kingdom.
1 Scope
This Technical Specification specifies a method for the determination of added inorganic iodine compounds,
including water-soluble iodine compounds of natural origin, in dietetic foods by inductively coupled plasma
mass spectrometry (ICP-MS).
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.
EN 13804, Foodstuffs – Determination of trace elements – Performance criteria, general considerations and
sample preparation.
3 Principle
Iodine compounds, added to dietetic foods, are extracted with a strong alkaline reagent at elevated
temperature. After the removing of undissolved components, the nebulized solution is atomized and ionized in
an inductively coupled argon plasma. The ions are extracted from the plasma by a system of sampler and
skimmer cones, separated in a mass spectrometer on the basis of their mass/charge ratio and determined
using a pulse counting detector system.
WARNING — The use of this document may involve hazardous materials, operations and equipment.
This document does not purport to address all the safety problems associated with its use. It is the
responsibility of the user of this document to establish appropriate safety and health practices and
determine the applicability or regulatory limitations prior to use.
4 Reagents
4.1 General
The concentration of iodine in the reagents and water used shall be low enough not to affect the results of
determination.
+ -
4.2 Tetramethylammonium hydroxide (TMAH = (CH ) N OH ) solution,
3 4
mass concentration c = 250 g/l, suitable for trace analysis with an iodine content of less than 1 µg/l.
4.3 Diluted tetramethylammonium hydroxide (TMAH) solution
Dilute TMAH solution for preparing the zero member compensation and calibration solutions, with a
concentration to suit that of the test solution (see 7.3).
Prepare e.g. a 0,5 % TMAH solution by diluting 1,0 ml of TMAH solution (4.2) to 50 ml with water.
4.4 Stock solutions
4.4.1 General
Commercial stock solutions may be used as an alternative to the solutions described below.
4.4.2 Iodine stock solution ( KIO ), c = 1 000 mg/l
Dissolve 1,6864 g of potassium iodate in water and dilute to 1 l.
c = 1 000 mg/l
4.4.3 Tellurium stock solution,
Dissolve 1,2508 g of tellurium dioxide (TeO ) in 4 mol/l hydrochloric acid and dilute to 1 l.
4.5 Standard solutions
4.5.1 Iodine standard solution, c = 10 mg/l
Pipette 1 ml of the iodine stock solution (4.4.2) into a 100 ml volumetric flask and dilute to the mark with water.
This solution is stable for about four weeks and is used to prepare the reference solutions in 4.6.
4.5.2 Tellurium standard solution (internal standard)
Tellurium has proved satisfactory as an internal standard for determining iodine since it has a mass in a
comparable range and an ionization energy similar to that of iodine. The original tellurium content in the
sample to be analysed shall be negligible, but if that is not the case, another suitable internal standard shall be
used.
Prepare e.g. a 10 mg/l standard tellurium solution by pipetting 1 ml of the tellurium stock solution (4.4.3) into a
100 ml volumetric flask and dilute to the mark with water. This solution is stable for about four weeks.
4.6 Iodine reference solutions
4.6.1 General
The reference solution concentrations specified below are given as an example and may be modified to suit
the sensitivity of the apparatus and the concentration range to be covered. The linear range of the detector
system shall not be exceeded.
The TMAH concentrations in the reference solutions shall be approximately equal to that of the test solution.
4.6.2 Reference solution 1, c = 10 µg/l
Pipette 25 µl of standard solution (4.5.1) into a 25 ml volumetric flask and dilute to the mark with diluted TMAH
solution (4.3).
4.6.3 Reference solution 2, c = 40 µg/l
Pipette 100 µl of standard solution (4.5.1) into a 25 ml volumetric flask and dilute to the mark with diluted
TMAH solution (4.3).
4.6.4 Reference solution 3, c = 200 µg/l
Pipette 500 µl of standard solution (4.5.1) into a 25 ml volumetric flask and dilute to the mark with diluted
TMAH solution (4.3).
The reference solutions shall be prepared freshly every day.
4.7 Iodine calibration solutions
4.7.1 General
To calibrate the analytical system, the internal standard shall be added to the reference solutions (4.6) in a
concentration high enough to reach a stable detector count rate. The calibration, zero member compensation
and test solutions shall contain the same amount of internal standard. The following solutions are
recommended.
4.7.2 Calibration solution 1
Pipette 0,5 ml of standard tellurium solution (4.5.2) into a vessel (5.8), add 10 ml of iodine reference solution
(4.6.1) and mix.
4.7.3 Calibration solution 2
Pipette 0,5 ml of standard tellurium solution (4.5.2) into a vessel (5.8), add 10 ml of iodine reference solution
(4.6.2) and mix.
4.7.4 Calibration solution 3
Pipette 0,5 ml of tellurium standard solution (4.5.2) into a vessel (5.8), add 10 ml of iodine reference solution
(4.6.3) and mix.
The calibration solutions shall be prepared freshly every day.
4.8 Zero member compensation solution, containing water and the same amount of TMAH and
internal standard as the test solution.Pipette e.g. 0,5 ml of tellurium standard solution (4.5.2) into a vessel
(5.9), and mix with 10 ml of diluted TMAH solution (4.3).
5 Apparatus and equipment
5.1 General
To minimize the blank, all apparatus that comes into direct contact with the sample and the solutions used
shall be carefully pretreated with a diluted TMAH solution (e.g. as in 4.3) and then rinsed with water.
5.2 Vessels, gastight, sealable quartz or glass, of capacity 30 ml to 100 ml.
As an alternative, plastic vessels that can be gastightly sealed and are able to withstand a temperature of not
less than 110 °C (e.g. made of polypropylene, high-density polyethylene or polyfluorine (such as PFA)) may
be used.
NOTE If plastic vessels are repeatedly used, there is a risk of higher blanks, in particular if samples having fairly high
iodine contents are extracted in them.
of capacity 5 ml to 25 ml, preferably with a bayonet-like connection (e.g. Luer lock )
5.3 Plastic syringes,
and a membrane filter, as a dispensable syringe attachment, having a pore size of 5,0 µm, with a connection
fitting the syringe.
5.4 Ultracentrifuge, as an alternative to 5.3., having an acceleration of not less than 10 000 g and
equipped with suitable rotors or adapters for accommodating vessels that can be sealed gastight.
5.5 Membrane filter, as dispensable syringe attachment, having a pore size of 0,45 µm, with a
connection fitting the syringes in 5.3.
NOTE Membrane filters sometimes give different blanks depending on the filter manufacturer and the batch number.
5.6 Drying oven, capable of being maintained at temperatures of (90 ± 3) °C.
5.7 ICP - mass spectrometer (ICP-MS), with inductively coupled plasma as ionization unit, quartz
burner, nebulizing chamber, nebulizer, sample feed device and optionally an automatic sampler.
5.8 Vessels for test solution or for automatic sampler.
6 Sampling
6.1 General
The conditions for sampling as outlined in EN 13804 have to be followed.
6.2 Sampling procedure
To prevent any change in the iodine content between sample collection and analysis, the sample shall be
stored in a tightly sealable vessel or in the original vessel and refrigerated, avoiding prolonged contact with air
and exposure to light.
7 Procedure
7.1 Sample preparation
Homogenize the sample using suitable equipment and avoiding excessive heating.
7.2 Iodine extraction
Weigh to the nearest 3 mg, approximately 200 m
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.