SIST EN 16319:2013
(Main)Fertilizers - Determination of trace elements - Determination of cadmium, chromium, lead and nickel by inductively coupled plasma-atomic emission spectrometry (ICP-AES) after aqua regia dissolution
Fertilizers - Determination of trace elements - Determination of cadmium, chromium, lead and nickel by inductively coupled plasma-atomic emission spectrometry (ICP-AES) after aqua regia dissolution
This European Standard specifies a method for the determination of the content of cadmium, chromium, nickel and lead in fertilizers with inductively coupled plasma-atomic emission spectrometry (ICP-AES) after extraction with aqua regia. Limits of quantification are dependent on the sample matrix as well as on the instrument, but can roughly be expected to be 0,3 mg/kg for Cd and 1 mg/kg for Cr, Ni and Pb.
Düngemittel - Bestimmung von Elementspuren - Bestimmung von Cadmium, Chrom, Blei und Nickel mit Atomemissionsspektrometrie mit induktiv gekoppeltem Plasma (ICP-AES) nach Königswasseraufschluss
Diese Europäische Norm legt ein Verfahren zur Bestimmung des Gehalts an Cadmium, Chrom, Nickel und Blei in Düngemitteln mit Atomemissionsspektrometrie mit induktiv gekoppeltem Plasma (ICP-AES) nach Königswasseraufschluss fest. Die Bestimmungsgrenzen sind sowohl von der Probenmatrix als auch vom verwendeten Gerät abhängig, werden jedoch etwa bei 0,3 mg/kg für Cd und 1 mg/kg für Cr, Ni und Pb erwartet.
ANMERKUNG Aufgrund signifikanter Störungen durch Cu, Fe und Mn können bei Anwendung dieses Verfahrens für Düngemittelmatrizes mit hohen Konzentrationen (≥ 10 %) dieser Spurennährstoffe keine zuverlässigen Ergebnisse ausgewiesen werden.
Engrais - Dosage des éléments traces - Détermination du cadmium, chromium, plomb et nickel par spectrométrie d'émission atomique avec plasma induit par haute fréquence (ICP-AES) après digestion à l'eau régale
La présente norme européenne spécifie une méthode permettant de déterminer la teneur en cadmium, chrome, nickel et plomb dans les engrais par spectrométrie d’émission atomique avec plasma à couplage inductif (ICP-AES) après extraction à l’eau régale. Les limites de quantification dépendent de la matrice de l’échantillon ainsi que de l’instrument, mais peuvent être attendues de l’ordre de 0,3 mg/kg pour Cd et 1 mg/kg pour Cr, Ni et Pb.
NOTE Du fait d’une interférence significative du Cu, Fe et Mn, aucun résultat valide ne peut être donné en utilisant cette méthode pour les matrices engrais contenants des concentrations élevés (≥ 10%) en ces oligo-éléments.
Gnojila - Določevanje elementov v sledovih - Določevanje kadmija, kroma, svinca in niklja z atomsko emisijsko spektrometrijo z induktivno sklopljeno plazmo (ICP-AES) po raztapljanju v zlatotopki
Ta evropski standard določa metodo za določevanje vsebnosti kadmija, kroma, niklja in svinca v gnojilih z atomsko emisijsko spektrometrijo z induktivno sklopljeno plazmo (ICP-AES) po ekstrakciji z zlatotopko. Meje kvantifikacije so odvisne od matrice vzorca in instrumenta, vendar za Cd običajno znašajo približno 0,3 mg/kg, za Cr, Ni in Pb pa 1 mg/kg.
General Information
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Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Düngemittel - Bestimmung von Elementspuren - Bestimmung von Cadmium, Chrom, Blei und Nickel mit Atomemissionsspektrometrie mit induktiv gekoppeltem Plasma (ICP-AES) nach KönigswasseraufschlussEngrais - Dosage des éléments traces - Détermination du cadmium, chromium, plomb et nickel par spectrométrie d'émission atomique avec plasma induit par haute fréquence (ICP-AES) après digestion à l'eau régaleFertilizers - Determination of trace elements - Determination of cadmium, chromium, lead and nickel by inductively coupled plasma-atomic emission spectrometry (ICP-AES) after aqua regia dissolution65.080GnojilaFertilizersICS:Ta slovenski standard je istoveten z:EN 16319:2013SIST EN 16319:2013en,fr,de01-december-2013SIST EN 16319:2013SLOVENSKI
STANDARDSIST-TS CEN/TS 16319:20121DGRPHãþD
SIST EN 16319:2013
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 16319
October 2013 ICS 65.080 Supersedes CEN/TS 16319:2012English Version
Fertilizers - Determination of trace elements - Determination of cadmium, chromium, lead and nickel by inductively coupled plasma-atomic emission spectrometry (ICP-AES) after aqua regia dissolution
Engrais - Dosage des éléments trace - Détermination du cadmium, chrome, plomb et nickel par spectrométrie d'émission atomique avec plasma induit par haute fréquence (ICP-AES) après digestion à l'eau régale
Düngemittel - Bestimmung von Elementspuren - Bestimmung von Cadmium, Chrom, Blei und Nickel mit Atomemissionsspektrometrie mit induktiv gekoppeltem Plasma (ICP-AES) nach Königswasseraufschluss This European Standard was approved by CEN on 15 September 2013.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre:
Avenue Marnix 17,
B-1000 Brussels © 2013 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 16319:2013: ESIST EN 16319:2013
EN 16319:2013 (E) 2 Contents Page Foreword .3 1 Scope .4 2 Normative references .4 3 Terms and definitions .4 4 Principle .4 5 Sampling and sample preparation .4 6 Reagents .4 7 Apparatus .5 8 Procedure .6 8.1 General .6 8.2 Preparation of the test solution .6 8.2.1 General .6 8.2.2 Preparation .7 8.3 Preparation of the test solution for the correction of matrix effects by spike recovery .7 8.4 Preparation of the blank test solution .8 8.5 Preparation of the calibration solutions for the analysis of cadmium, chromium, nickel and lead .8 8.6 Determination of cadmium, chromium, nickel and lead by ICP-AES .8 8.6.1 General .8 8.6.2 Determination by ICP-AES .8 9 Calculation and expression of the results . 10 9.1 External calibration. 10 9.2 Correction for spike recovery . 10 9.3 Standard addition method . 11 9.4 Calculation of the element content in the sample . 12 10 Precision . 12 10.1 Inter-laboratory tests . 12 10.2 Repeatability . 12 10.3 Reproducibility . 12 11 Test report . 14 Annex A (informative)
Results of the inter-laboratory test . 15 A.1 Inter-laboratory tests . 15 A.2 Statistical results for the determination of cadmium, chromium, lead and nickel . 15 Bibliography . 17
SIST EN 16319:2013
EN 16319:2013 (E) 3 Foreword This document (EN 16319:2013) has been prepared by Technical 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 April 2014, and conflicting national standards shall be withdrawn at the latest by April 2014. 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. This document supersedes CEN/TS 16319:2012. The following changes have been made to the former edition: the CEN Technical Specification has been adopted as a European Standard; an explanation concerning possible interferences when using this method for the determination of Cd, Cr, Ni and Pb in micro-nutrient fertilizers has been added as a NOTE to Clause 1;
the document has been editorially revised. This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
SIST EN 16319:2013
EN 16319:2013 (E) 4 1 Scope This European Standard specifies a method for the determination of the content of cadmium, chromium, nickel and lead in fertilizers with inductively coupled plasma-atomic emission spectrometry (ICP-AES) after extraction with aqua regia. Limits of quantification are dependent on the sample matrix as well as on the instrument, but can roughly be expected to be 0,3 mg/kg for Cd and 1 mg/kg for Cr, Ni and Pb. NOTE Due to significant interference from Cu, Fe and Mn, no valid results can be reported using this method for fertilizer matrices containing high concentrations (≥ 10 %) of these micro-nutrients. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 1482-2, Fertilizers and liming materials — Sampling and sample preparation — Part 2: Sample preparation EN 12944-1:1999, Fertilizers and liming materials and soil improvers — Vocabulary — Part 1: General terms EN 12944-2:1999, Fertilizers and liming materials and soil improvers — Vocabulary — Part 2: Terms relating to fertilizers EN ISO 3696, Water for analytical laboratory use — Specification and test methods (ISO 3696) 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 12944-1:1999 and EN 12944-2:1999 apply. 4 Principle Cadmium, chromium, nickel and lead are extracted from the sample with aqua regia and conventional boiling. The concentrations in the extract are measured by inductively coupled plasma–atomic emission spectrometry (ICP-AES), with axial or radial viewing. 5 Sampling and sample preparation Sampling is not part of the method specified in this European Standard. A recommended sampling method is given in EN 1482-1. Sample preparation shall be carried out in accordance with EN 1482-2. 6 Reagents Use only reagents of recognized analytical grade. Commercially available stock solutions shall be replaced according to the specifications from the supplier or after one year if prepared in the laboratory from available salts. Standard solutions shall be renewed monthly as a general rule. 6.1 Water, conforming to grade 2 according to EN ISO 3696. 6.2 Hydrochloric acid, c(HCl) = 12 mol/l; 37 % volume fraction;
≈ 1,18 g/ml. 6.3 Nitric acid, c(HNO3) = 16 mol/l; not less than 65 % volume fraction;
≈ 1,42 g/ml. SIST EN 16319:2013
EN 16319:2013 (E) 5
6.4 Mixed solution of 0,8 mol/l nitric acid and 1,8 mol/l hydrochloric acid. Mix 150 ml of hydrochloric acid (6.2) and 50 ml nitric acid (6.3) to 1,0 l of water (6.1). 6.5 Standard stock solutions, cadmium, chromium, nickel and lead standard stock solutions, e.g.
= 1 000 mg/l for each element. Use suitable stock solutions. Both single-element stock solutions and multi-element stock solutions with adequate specification stating the acid used and the preparation technique are commercially available. It is recommended to use commercially available standard stock solutions for cadmium, chromium, nickel and lead. 6.6 Working standard solutions. Depending on the scope, different working standard solutions may be necessary. In general, when combining elements in working standard solutions, their chemical compatibility shall be regarded. Spectral interferences from other elements present in working standard solutions also need to be considered. Various combinations of elements at different concentrations may be used, provided that the standard stock solutions (6.5) are diluted with the same acid and in equal concentration as the acid in the test solution.
NOTE In equal concentrations (in mg/l), cadmium, chromium, nickel and lead are compatible in a multi-element standard solution for the determination by ICP-AES for this application. 6.6.1 Working standard solution I,
= 100 mg/l for cadmium, chromium, nickel and lead.
Dilute 10,0 ml of each standard stock solution of cadmium, chromium, nickel and lead (6.5) to 100,0 ml with the mixed acid solution (6.4) in the same 100 ml flask. If non-equal concentrations of cadmium, chromium, nickel and lead are needed, dilute the required volumes into 100,0 ml. This solution is used to prepare spiked test solutions and standard and calibration solutions. 6.6.2 Working standard solution II,
= 10 mg/l for cadmium, chromium, nickel and lead. Dilute 10,0 ml of the working standard solution I of cadmium, chromium, nickel and lead (6.6.1) to 100,0 ml with the mixed acid solution (6.4) in a 100 ml flask. If non-equal concentrations of cadmium, chromium, nickel and lead are needed, dilute the require volume from the standard stock solutions (6.5) into 100,0 ml. This solution is used to prepare spiked test solutions and calibration solutions. 7 Apparatus 7.1 Common laboratory glassware. 7.2 Analytical balance, capable of weighing to an accuracy of 1 mg. 7.3 Inductively coupled plasma-atomic emission spectrometer, with axial or radial viewing of the plasma and with suitable background correction. The settings of the working conditions (e.g. gas flows, RF or plasma power, sample uptake rate, integration time and number of replicates) shall be optimized according to the manufacturer’s instructions. Radial viewing of the plasma may be used if it can be shown that the limits of quantification for cadmium, chromium, nickel and lead are below the required legal limit values. The use of axial orientation of the viewing optics requires good control of the matrix effects coming from "easily ionisable elements" (i.e. the influence of easily ionisable elements in varying concentrations on the signal intensities of the analytes).
SIST EN 16319:2013
EN 16319:2013 (E) 6 For alkali-elements, this can be achieved by adding caesium-chloride solution (CsCl). In general, matrix matching of calibration solutions or calibration by standard additions with several calibration standards will correct accurately for these matrix effects. Spike recovery of one known standard combined with external calibration can, if used properly, also correct sufficiently for matrix effects (see 8.1). Correction by internal standardization is also a good option, but the accuracy of the measurements after internal standard correction should be validated properly prior to use on unknown fertilizer samples. 7.4 Dilutor. Instrument used for automated volumetric dilutions or other appropriate equipment (e.g. pipettes and volumetric glassware) to perform dilutions. The precision and accuracy of this type of equipment for volumetric dilutions shall be established, and controlled and documented regularly.
7.5 Ash-free filter paper, i.e. Whatman® 589/21) or equivalent quality. 8 Procedure 8.1 General Calibrations by standard additions with several standards or by matrix matching are very powerful calibration techniques and can be used to accurately correct for matrix effects from easy-ionisable elements (multiplicative matrix effects). Additive matrix effects (i.e. spectral interferences) are not corrected for with standard additions calibration. For matrix matching, additive matrix effects will be corrected for when the added matrix is the cause of the matrix effect. The main drawback of calibration by standard addition with several standards is the requirement for a calibration function for each sample type, which is a time consuming process. For matrix matching a profound knowledge of the sample matrix is needed, which is not always necessarily available. These two techniques may thus not be practical to use in routine fertilizer laboratories. Correction by internal standardization is also a good option, but the accuracy of the measurements after internal standard correction should be validated properly prior to use on unknown fertilizer samples. It is therefore suggested that calibrations are to be performed by means of external calibration and correction of matrix effects by addition of one known spike of a standard solution (spike recovery). The method of external calibration and correction for spike recovery allows for the analysis of fertilizers with unknown matrix composition or with a matrix that cannot be synthetically imitated easily. This calibration technique may not be as precise as calibration by standard additions with several standards but the increased uncertainty is small compared to the total uncertainty of the method, if the total analyte concentration is in the linear working range after the spike and the added spike corresponds to at least a doubling of the analyte concentration. Many matrix errors can be compensated for by this procedure, if they are not additive (e.g. spectral interferences). Aliquots of the sample solution are analyzed by the means of external calibration and then one aliquot is spiked with known concentrations of the analytes without changing the matrix of the s
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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Düngemittel - Bestimmung von Elementspuren - Bestimmung von Cadmium, Chrom, Blei und Nickel mit Atomemissionsspektrometrie mit induktiv gekoppeltem Plasma (ICP-AES) nach KönigswasseraufschlussEngrais - Dosage des éléments traces - Détermination du cadmium, chromium, plomb et nickel par spectrométrie d'émission atomique avec plasma induit par haute fréquence (ICP-AES) après digestion à l'eau régaleFertilizers - Determination of trace elements - Determination of cadmium, chromium, lead and nickel by inductively coupled plasma-atomic emission spectrometry (ICP-AES) after aqua regia dissolution65.080GnojilaFertilizersICS:Ta slovenski standard je istoveten z:FprEN 16319kSIST FprEN 16319:2013en,fr,de01-maj-2013kSIST FprEN 16319:2013SLOVENSKI
STANDARD
kSIST FprEN 16319:2013
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
FINAL DRAFT
FprEN 16319
March 2013 ICS 65.080 Will supersede CEN/TS 16319:2012English Version
Fertilizers - Determination of trace elements - Determination of cadmium, chromium, lead and nickel by inductively coupled plasma-atomic emission spectrometry (ICP-AES) after aqua regia dissolution
Engrais - Dosage des éléments trace - Détermination du cadmium, chrome, plomb et nickel par spectrométrie d'émission atomique avec plasma induit par haute fréquence (ICP-AES) après digestion à l'eau régale
Düngemittel - Bestimmung von Elementspuren - Bestimmung von Cadmium, Chrom, Blei und Nickel mit Atomemissionsspektrometrie mit induktiv gekoppeltem Plasma (ICP-AES) nach Königswasseraufschluss This draft European Standard is submitted to CEN members for unique acceptance procedure. It has been drawn up by the Technical Committee CEN/TC 260.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre:
Avenue Marnix 17,
B-1000 Brussels © 2013 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. FprEN 16319:2013: EkSIST FprEN 16319:2013
FprEN 16319:2013 (E) 2 Contents Page Foreword .3 1 Scope .4 2 Normative references .4 3 Terms and definitions .4 4 Principle .4 5 Sampling and sample preparation .4 6 Reagents .4 7 Apparatus .5 8 Procedure .6 8.1 General .6 8.2 Preparation of the test solution .6 8.2.1 General .6 8.2.2 Preparation .7 8.3 Preparation of the test solution for the correction of matrix effects by spike recovery .7 8.4 Preparation of the blank test solution .8 8.5 Preparation of the calibration solutions for the analysis of cadmium, chromium, nickel and lead .8 8.6 Determination of cadmium, chromium, nickel and lead by ICP-AES .8 8.6.1 General .8 8.6.2 Determination by ICP-AES .8 9 Calculation and expression of the results . 10 9.1 External calibration. 10 9.2 Correction for spike recovery . 10 9.3 Standard addition method . 11 9.4 Calculation of the element content in the sample . 12 10 Precision . 12 10.1 Inter-laboratory tests . 12 10.2 Repeatability . 12 10.3 Reproducibility . 12 11 Test report . 14 Annex A (informative)
Results of the inter-laboratory test . 15 A.1 Inter-laboratory tests . 15 A.2 Statistical results for the determination of cadmium, chromium, lead and nickel . 15 Bibliography . 17
kSIST FprEN 16319:2013
FprEN 16319:2013 (E) 3 Foreword This document (FprEN 16319:2013) has been prepared by Technical Committee CEN/TC 260 “Fertilizers and liming materials”, the secretariat of which is held by DIN. This document is currently submitted to the Unique Acceptance Procedure. This document will supersede CEN/TS 16319:2012. The following changes have been made to the former edition: a) the CEN Technical Specification has been adopted as a European Standard; b) an explanation concerning possible interferences when using this method for the determination of Cd, Cr, Ni and Pb in micro-nutrient fertilizers has been added as a NOTE to Clause 1;
c) the document has been editorially revised. This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association. kSIST FprEN 16319:2013
FprEN 16319:2013 (E) 4 1 Scope This European Standard specifies a method for the determination of the content of cadmium, chromium, nickel and lead in fertilizers with inductively coupled plasma-atomic emission spectrometry (ICP-AES) after extraction with aqua regia. Limits of quantification are dependent on the sample matrix as well as on the instrument, but can roughly be expected to be 0,3 mg/kg for Cd and 1 mg/kg for Cr, Ni and Pb. NOTE Due to significant interference from Cu, Fe and Mn, no valid results can be reported using this method for fertilizer matrices containing high concentrations (≥ 10 %) of these micro-nutrients. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 1482-2, Fertilizers and liming materials — Sampling and sample preparation — Part 2: Sample preparation EN 12944-1:1999, Fertilizers and liming materials and soil improvers — Vocabulary — Part 1: General terms EN 12944-2:1999, Fertilizers and liming materials and soil improvers — Vocabulary — Part 2: Terms relating to fertilizers EN ISO 3696, Water for analytical laboratory use — Specification and test methods (ISO 3696) 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 12944-1:1999 and EN 12944-2:1999 apply. 4 Principle Cadmium, chromium, nickel and lead are extracted from the sample with aqua regia and conventional boiling. The concentrations in the extract are measured by inductively coupled plasma–atomic emission spectrometry (ICP-AES), with axial or radial viewing. 5 Sampling and sample preparation Sampling is not part of the method specified in this European Standard. A recommended sampling method is given in EN 1482-1. Sample preparation shall be carried out in accordance with EN 1482-2. 6 Reagents Use only reagents of recognized analytical grade. Commercially available stock solutions shall be replaced according to the specifications from the supplier or after one year if prepared in the laboratory from available salts. Standard solutions shall be renewed monthly as a general rule. 6.1 Water, conforming to grade 2 according to EN ISO 3696. 6.2 Hydrochloric acid, c(HCl) = 12 mol/l; 37 % volume fraction;
≈ 1,18 g/ml. 6.3 Nitric acid, c(HNO3) = 16 mol/l; not less than 65 % volume fraction,
≈ 1,42 g/ml. kSIST FprEN 16319:2013
FprEN 16319:2013 (E) 5 6.4 Mixed solution of 0,8 mol/l nitric acid and 1,8 mol/l hydrochloric acid. Mix 150 ml of hydrochloric acid (6.2) and 50 ml nitric acid (6.3) to 1,0 l of water (6.1). 6.5 Standard stock solutions, cadmium, chromium, nickel and lead standard stock solutions, e.g.
= 1 000 mg/l for each element. Use suitable stock solutions. Both single-element stock solutions and multi-element stock solutions with adequate specification stating the acid used and the preparation technique are commercially available. It is recommended to use commercially available standard stock solutions for cadmium, chromium, nickel and lead. 6.6 Working standard solutions. Depending on the scope, different working standard solutions may be necessary. In general, when combining elements in working standard solutions, their chemical compatibility shall be regarded. Spectral interferences from other elements present in working standard solutions also need to be considered. Various combinations of elements at different concentrations may be used, provided that the standard stock solutions (6.5) are diluted with the same acid and in equal concentration as the acid in the test solution.
NOTE In equal concentrations (in mg/l), cadmium, chromium, nickel and lead are compatible in a multi-element standard solution for the determination by ICP-AES for this application. 6.6.1 Working standard solution I,
= 100 mg/l for cadmium, chromium, nickel and lead.
Dilute 10,0 ml of each standard stock solution of cadmium, chromium, nickel and lead (6.5) to 100,0 ml with the mixed acid solution (6.4) in the same 100 ml flask. If non-equal concentrations of cadmium, chromium, nickel and lead are needed, dilute the required volumes into 100,0 ml. This solution is used to prepare spiked test solutions and standard and calibration solutions. 6.6.2 Working standard solution II,
= 10 mg/l for cadmium, chromium, nickel and lead. Dilute 10,0 ml of the working standard solution I of cadmium, chromium, nickel and lead (6.6.1) to 100,0 ml with the mixed acid solution (6.4) in a 100 ml flask. If non-equal concentrations of cadmium, chromium, nickel and lead are needed, dilute the require volume from the standard stock solutions (6.5) into 100,0 ml. This solution is used to prepare spiked test solutions and calibration solutions. 7 Apparatus 7.1 Common laboratory glassware. 7.2 Analytical balance, capable of weighing to an accuracy of 1 mg. 7.3 Inductively coupled plasma-atomic emission spectrometer, with axial or radial viewing of the plasma and with suitable background correction. The settings of the working conditions (e.g. gas flows, RF or plasma power, sample uptake rate, integration time and number of replicates) shall be optimised according to the manufacturer’s instructions. Radial viewing of the plasma may be used if it can be shown that the limits of quantification for cadmium, chromium, nickel and lead are below the required legal limit values. The use of axial orientation of the viewing optics requires good control of the matrix effects coming from "easily ionisable elements" (i.e. the influence of easily ionisable elements in varying concentrations on the signal intensities of the analytes).
kSIST FprEN 16319:2013
FprEN 16319:2013 (E) 6 For alkali-elements, this can be achieved by adding caesium-chloride solution (CsCl). In general, matrix matching of calibration solutions or calibration by standard additions with several calibration standards will correct accurately for these matrix effects. Spike recovery of one known standard combined with external calibration can, if used properly, also correct sufficiently for matrix effects (see 8.1). Correction by internal standardisation is also a good option, but the accuracy of the measurements after internal standard correction should be validated properly prior to use on unknown fertilizer samples. 7.4 Dilutor. Instrument used for automated volumetric dilutions or other appropriate equipment (e.g. pipettes and volumetric glassware) to perform dilutions. The precision and accuracy of this type of equipment for volumetric dilutions shall be established, and controlled and documented regularly.
7.5 Ash-free filter paper,
i.e. Whatman 589/2 or equivalent quality. 8 Procedure 8.1 General Calibrations by standard additions with several standards or by matrix matching are very powerful calibration techniques and can be used to accurately correct for matrix effects from easy-ionisable elements (multiplicative matrix effects). Additive matrix effects (i.e. spectral interferences) are not corrected for with standard additions calibration. For matrix matching, additive matrix effects will be corrected for when the added matrix is the cause of the matrix effect. The main drawback of calibration by standard addition with several standards is the requirement for a calibration function for each sample type, which is a time consuming process. For matrix matching a profound knowledge of the sample matrix is needed, which is not always necessarily available. These two techniques may thus not be practical to use in routine fertilizer laboratories. Correction by internal standardisation is also a good option, but the accuracy of the measurements after internal standard correction should be validated properly prior to use on unknown fertilizer samples. It is therefore suggested that calibrations are to be performed by means of external calibration and correction of matrix effects by addition of one known spike of a standard solution (spike recovery). The method of external calibration and correction for spike recovery allows for the analysis of fertilisers with unknown matrix composition or with a matrix that cannot be synthetically imitated easily. This calibration technique may not be as precise as calibration by standard additions with several standards but the increased uncertainty is small compared to the total uncertainty of the method, if the total analyte concentration is in the linear working range after the spike and the added spike corresponds to at least a doubling of the analyte concentration. Many matrix errors can be compensated for by this procedure, if they are not additive (e.g. spectral interferences). Aliquots of the sample solution are analysed by the means of external calibration and then one aliquot is spiked with known concentrations of the analytes without changing the matrix of the sample solution. The calculated spike recovery is then used to correct the concentration calculated from the external calibration function. The concentra
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