EN 16320:2013

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Düngemittel - Bestimmung von Elementspuren - Bestimmung von Quecksilber mit Verdampfungstechnik (VG) nach KönigswasseraufschlussEngrais - Dosage des éléments traces - Détermination du mercure par génération de vapeur (VG) après digestion à l'eau régaleFertilizers - Determination of trace elements - Determination of mercury by vapour generation (VG) after aqua regia dissolution65.080GnojilaFertilizersICS:Ta slovenski standard je istoveten z:EN 16320:2013SIST EN 16320:2013en,fr,de01-december-2013SIST EN 16320:2013SLOVENSKI
STANDARDSIST-TS CEN/TS 16320:20121DGRPHãþD

EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 16320
October 2013 ICS 65.080 Supersedes CEN/TS 16320:2012English Version
Fertilizers - Determination of trace elements - Determination of mercury by vapour generation (VG) after aqua regia dissolution Engrais - Dosage des éléments traces - Détermination du mercure par génération de vapeur (VG) après digestion à l'eau régale
Düngemittel - Bestimmung von Elementspuren - Bestimmung von Quecksilber mit Verdampfungstechnik (VG) nach Königswasseraufschluss This European Standard was approved by CEN on 29 August 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.
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Results of the inter-laboratory test . 14 Bibliography. 15
6.1 Water, conforming to grade 2 of EN ISO 3696. 6.2 Hydrochloric acid, c(HCl) = 12 mol/l; 37
≈ 1,18 g/ml. 6.3 Nitric acid, c(HNO3) = 16 mol/l; not less than 65 % volume fraction, ρ ≈ 1,42 g/ml. SIST EN 16320:2013

= 1 000 mg/l. Use suitable stock solutions. Single-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 mercury. 6.6 Working standard solutions. Depending on the scope, different working standard solutions may be necessary. In general, the stability of mercury working standard solutions should be checked. 6.6.1 Working standard solution I,
= 10 mg/l for mercury.
Dilute 1,00 ml of the standard stock solution for mercury (6.5) to 100,0 ml with the mixed acid solution (6.4). This solution is used to prepare 200 µg/l mercury working standard solution.
6.6.2 Working standard solution II,
= 200 g/l for mercury. Dilute 2,00 ml of the 10 mg/l mercury working standard solution I (6.6.1) to 100,0 ml with the mixed acid solution (6.4). This solution is used to prepare spiked test solutions and calibration solutions. 6.7 Reducing agents. 6.7.1 General. Tin(II) chloride or sodium borohydride may be used as the reducing agent, but it is not advisable to use the two reagents alternately. Observe the instructions of the manufacturers of the apparatus. The concentration by mass of the reducing agent solutions may be varied to suit the system, and the relevant information provided by the manufacturer of the apparatus shall be observed. 6.7.2 Tin(II) chloride solution, (SnCl2·2H2O) = 100 g/l. Dissolve 50 g of tin(II) chloride in approximately 100 ml of hydrochloric acid (6.2) in a 500 ml volumetric flask and dilute to the mark. Prepare a fresh solution daily. 6.7.3 Sodium borohydride solution, e.g.
= 2 g/l. Dissolve 2 g of sodium hydroxide pellets in water, add 2 g of sodium borohydride and dilute to 1 000 ml with water (6.1). Prepare a fresh solution daily and, when necessary, filter before use. When the analysis procedure is of a longer time, it is recommended to cool the sodium borohydride solution (i.e. with ice around the flask) during its use in the vapour generation ICP-AES or AAS measurement. WARNING — It is essential to observe the safety instructions for working with sodium borohydride. Sodium borohydride forms hydrogen with acids and this can result in an explosive air/hydrogen mixture. A permanent extraction system shall be provided at the point where measurements are carried out. 7 Apparatus 7.1 Common laboratory glassware. 7.2 Analytical balance, capable of weighing to an accuracy of 1 mg. SIST EN 16320:2013

7.5.2 Element-specific lamp for mercury. 7.6 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.
7.7 Ash-free filter paper, i.e. Whatman 589/2®1) 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. 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 easily imitated synthetically. 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 concentration of the spikes shall be in the linear working range of the analytical detection tec
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