1、BRITISH STANDARDBS EN 14888:2005Fertilizers and liming materials Determination of cadmium contentThe European Standard EN 14888:2005 has the status of a British StandardICS 65.080g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g
2、54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 14888:2005This British Standard was published under the authority of the Standards Policy and Strategy Committee on 4 January 2006 BSI 4 January 2006ISBN 0 580 47404 6National forewordThis British Standard is the of
3、ficial English language version of EN 14888:2005.The UK participation in its preparation was entrusted to Technical Committee CII/37, Fertilizers and related chemicals, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary.
4、Cross-referencesThe British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or
5、of British Standards Online.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text;
6、present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK.Summary of pagesThis document comprises a front cover, an in
7、side front cover, the EN title page, pages 2 to 22, an inside back cover and a back cover.The BSI copyright notice displayed in this document indicates when the document was last issued.Amendments issued since publicationAmd. No. Date CommentsEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 14888Au
8、gust 2005ICS 65.080English versionFertilizers and liming materials - Determination of cadmiumcontentEngrais et amendements minraux basiques - Dosage ducadmiumDngemittel und Calcium-/Magnesium-Bodenverbesserungsmittel - Bestimmung desCadmiumgehaltesThis European Standard was approved by CEN on 27 Jun
9、e 2005.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained
10、 on application to the Central Secretariat or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretaria
11、t has the same status as the officialversions.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, S
12、lovakia,Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2005 CEN All rights of exploitation in any form and by any means reservedworldwide
13、for CEN national Members.Ref. No. EN 14888:2005: EEN 14888:2005 (E) 2 Contents Page Foreword 3 Introduction4 1 Scope .5 2 Normative references .5 3 Terms and definitions.5 4 Principle.5 5 Reagents6 6 Apparatus 7 7 Sampling and sample preparation.7 8 Procedure 8 9 Calculation and expression of the re
14、sults 10 10 Precision13 11 Test report .15 Annex A (informative) Results of inter-laboratory tests 16 Annex B (informative) Notes on the detection techniques, interferences and quantification19 Bibliography.22 EN 14888:2005 (E) 3 Foreword This document (EN 14888:2005) has been prepared by Technical
15、Committee CEN/TC 260 “Fertilizers and liming materials”, the secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by February 2006, and conflicting national standards
16、shall be withdrawn at the latest by February 2006. This European Standard has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association to provide a means of conforming to Essential Requirements of the Regulation (EC) No 2003/2003 of the European P
17、arliament and of the Council of 13 October 2003 relating to fertilizers. Once this standard is cited in the Official Journal of the European Communities under that Regulation and has been implemented as a national standard in at least one Member State, compliance with the normative clauses of this s
18、tandard confers, within the limits of the scope of this standard, a presumption of conformity with the relevant Essential Requirements of that Regulation and associated EFTA regulations. WARNING Other requirements and other EU Directives may be applicable to the product(s) falling within the scope o
19、f this standard. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland,
20、Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 14888:2005 (E) 4 Introduction Because flame atomic absorption spectrometry (flame AAS) and inductively coupled plasma-optical emission spectrometr
21、y (ICP-OES) are widely used techniques for the determination of cadmium, both are described in this European Standard (as method A and method B respectively). Much of the procedure and many of the reagents are common to both methods. EN 14888:2005 (E) 5 1 Scope This European Standard specifies two m
22、ethods for the determination of the cadmium content, after extraction with nitric acid, of solid mineral fertilizers and rock phosphates. It is not applicable to organic and organo-mineral fertilizers. It is applicable to the determination of cadmium contents greater than 1 mg/kg. 2 Normative refere
23、nces 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 1482, Sampling of solid fertilizers and l
24、iming materials EN ISO 3696:1995, Water for analytical laboratory use - Specification and test methods (ISO 3696:1987) 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 limit of detection smallest measured content from which it is possible to d
25、educe the presence of the analyte with reasonable statistical certainty NOTE The limit of detection is numerically equal to three times the standard deviation of the mean of blank determinations (n 10, where n is the number of measurements). 3.2 limit of quantification lowest content of the analyte
26、which can be measured with reasonable statistical certainty NOTE If both accuracy and precision are constant over a concentration range around the limit of detection, then the limit of quantification is numerically equal to ten times the standard deviation of the mean of blank determinations (n 10,
27、where n is the number of measurements). 4 Principle The cadmium is extracted from the fertilizer by means of a nitric acid digestion. Its concentration is measured either by flame atomic absorption spectrometry (Flame-AAS) (Method A) or by inductively coupled plasmaoptical emission spectrometry (ICP
28、-OES) (Method B). Both methods are relative techniques. Cadmium concentrations are determined by the standard addition method. EN 14888:2005 (E) 6 5 Reagents 5.1 General Use only reagents of recognized analytical grade, and water conforming to grade 2 of EN ISO 3696:1995. Stock solutions shall be re
29、placed after a maximum of one year, but the standard solution shall be renewed monthly as a minimum. If a stock solution is prepared directly from a metal, care needs to be taken to ensure that the metal used is free of surface oxide layers. WARNING Cadmium is highly toxic. It is essential that all
30、necessary measures are taken to avoid ingestion. 5.2 Nitric acid, 65 %, approximately 1,42 g/ml 5.3 Diluted nitric acid, diluted to a concentration of about 7 mol/l (1 + 1 volume fraction). Mix 1 volume of nitric acid (5.2) with 1 volume of water. 5.4 Diluted nitric acid, diluted to a concentration
31、of about 4,3 mol/l (1 + 3 volume fraction). Mix 1 volume of nitric acid (5.2) with 3 volumes of water. 5.5 Diluted nitric acid, diluted to a concentration of 2 % (volume fraction). Pipette 20,00 ml nitric acid (5.2) in a 1 000 ml volumetric flask and fill to the mark with water. 5.6 Cadmium stock so
32、lution, corresponding to 1 000 mg/l. Weigh to the nearest 0,1 mg, approximately 1,000 g of metallic cadmium (minimum purity 99,5 %) and dilute in a covered 250 ml glass beaker with 40 ml of nitric acid (5.4). Then add 100 ml of water. Boil to expel nitrous fumes, cool, transfer to a 1 000 ml volumet
33、ric flask and fill to the mark with water. NOTE Cadmium stock solution of 1 000 mg/l is also readily available commercially, and may be used instead. 5.7 Cadmium standard solution, corresponding to 50 mg/l. Pipette 50,00 ml of the cadmium stock solution (5.6) into a 1 000 ml volumetric flask and fil
34、l to the mark with the diluted 2 % nitric acid (5.5). EN 14888:2005 (E) 7 5.8 Cadmium standard solution, corresponding to 1 mg/l. Pipette 20,00 ml of the cadmium standard solution (5.7) into a 1 000 ml volumetric flask and fill to the mark with the diluted 2 % nitric acid (5.5). 6 Apparatus 6.1 Gene
35、ral Ordinary laboratory glassware. 6.2 Analytical balance, capable of weighing to an accuracy of 0,1 mg. 6.3 Laboratory grinder, capable of grinding to a particle size of less than or equal to 0,5 mm. 6.4 Electric hot plate, with temperature control. 6.5 Flame atomic absorption spectrometer The inst
36、rument shall be equipped with a cadmium source, a background correction system and a burner suitable for an air/acetylene flame. It shall be operated according to the manufacturers instructions. 6.6 Inductively coupled plasma Optical emission spectrometer The instrument shall be equipped with radial
37、 plasma as a minimum requirement; axial plasma is equally acceptable, as long as it can be shown that the results are statistically equal to the results obtained with radial plasma. Background correction shall also be performed. Settings of the working conditions (e.g. viewing height, gas flows, RF
38、or plasma power, sample uptake rate, integration time, number of replicates) shall be optimized according the manufacturers instructions. 7 Sampling and sample preparation 7.1 Sampling Sampling shall be carried out in accordance with EN 1482. 7.2 Sample preparation Grind the laboratory sample, using
39、 a grinder or mortar, until a particle size of 0,5 mm or less has been reached, and mix thoroughly for reasons of homogeneity. The grinding shall be done in conditions such that the substance is not appreciably heated. The operation is to be repeated as many times as is necessary and it shall be eff
40、ected as quickly as possible in order to prevent any gain or loss of constituents (water, ammonia). Place the whole ground sample in a flask which can be stoppered. Before any weighing is carried out for the analysis, mix the whole sample thoroughly. EN 14888:2005 (E) 8 7.3 Special cases of grinding
41、 Blended fertilizers: in this case, separation frequently occurs. It is therefore essential to grind to a particle size of 0,2 mm or less. Products, that decompose on heating: grinding shall be carried out in such a way as to avoid any heating. It is preferable in this case to use a mortar for grind
42、ing. 8 Procedure 8.1 Preparation of the test solution 8.1.1 Digestion Weigh to the nearest 0,1 mg an amount of test sample between 1 g and 12,5 g depending on the expected cadmium content (as specified in Table 1), into a beaker or reaction vessel. Moisten the sample with a small amount of water. Ad
43、d the appropriate amount of nitric acid (5.3), according to Table 1. Cover the beaker with a watch glass and boil gently for 30 min on a hot plate. In order to maintain the initial volume, add some more water during boiling if necessary. Cool, transfer to an appropriate volumetric flask and fill to
44、the mark with water. After homogenizing, filter through a dry filter into a dry container. Use the first portion of the filtrate to rinse the glassware and discard that part. If the determination is not carried out immediately, the container with the filtrate shall be stoppered. The filtrate will be
45、 used for the preparation of the final test solution as well as for the preparation of the calibration solutions (8.3). Table 1 Preparation of the test portion Expected (declared) content of cadmium in the fertilizer mg/kg 1 to 5 5 to 15 15 to 30 30 to 100 Mass of sample g 12,5 5 2,5 1 Volume of HNO
46、3ml (5.3) 125 50 25 10 Total volume of extract ml 250 250 250 250 Concentration of cadmium in extract mg/l 0,05 to 0,25 0,10 to 0,30 0,15 to 0,30 0,12 to 0,40 NOTE Masses and volumes of the extracts are chosen such that the concentrations in the solutions to be measured are above the typical limits
47、of quantification of flame AAS and ICP-OES, that the concentrations fall within their (linear) working area, and that salt concentrations are not too high. EN 14888:2005 (E) 9 8.1.2 Test solution Pipette 50,00 ml of the filtrate of the test portion (8.1.1) into a 100 ml volumetric flask and fill to
48、the mark with the diluted 2 % nitric acid (5.5). 8.2 Preparation of the blank test solution Carry out a blank test at the same time as the extraction, with only the reagents and follow the same procedure as before. 8.3 Preparation of the calibration solutions Calibration shall be performed by means
49、of the standard addition technique. NOTE An (external) calibration curve method can also be used instead of the standard addition method where the analytical results are demonstrated to be statistically equal. Appropriate matrix matching of the calibration solutions shall be performed if an (external) calibration method is used (see Annex B). 8.3.1 Addition 1 Pipette 50,00 ml of the filtrate of the test portion (8.1.1) into a 100 ml volumetric flask, add 2,00 ml of the cadmium standard solution of 1 mg/l (5.8), and fill to the mark with the diluted 2 % nitric acid
