1、September 2014 Translation by DIN-Sprachendienst.English price group 9No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).I
2、CS 13.080.10!%:P“2235845www.din.deDDIN EN ISO 17184Soil quality Determination of carbon and nitrogen by near-infraredspectrometry (NIRS) (ISO 17184:2014);English version EN ISO 17184:2014,English translation of DIN EN ISO 17184:2014-09Bodenbeschaffenheit Bestimmung von Kohlenstoff und Stickstoff dur
3、ch Nahinfrarotspektroskopie (NIRS)(ISO 17184:2014);Englische Fassung EN ISO 17184:2014,Englische bersetzung von DIN EN ISO 17184:2014-09Qualit du sol Dosage du carbone et de lazote par spectromtrie proche infrarouge (SPIR)(ISO 17184:2014);Version anglaise EN ISO 17184:2014,Traduction anglaise de DIN
4、 EN ISO 17184:2014-09www.beuth.deIn case of doubt, the German-language original shall be considered authoritative.Document comprises 14 pages 08.14 DIN EN ISO 17184:2014-09 2 A comma is used as the decimal marker. National foreword This document (EN ISO 17184:2014) has been prepared by Technical Com
5、mittee ISO/TC 190 “Soil quality” in collaboration with Technical Committee CEN/TC 345 “Characterization of soils” (Secretariat: NEN, Netherlands). The responsible German body involved in its preparation was the Normenausschuss Wasserwesen (DIN Standards Committee Water Practice), Working Committee N
6、A 119-01-02-02 UA Chemische und physikalische Verfahren of NA 119-01-02 AA Abfall- und Bodenuntersuchung. The DIN Standards corresponding to the International Standards referred to in this document are as follows: ISO 10694 DIN ISO 10694 ISO 11261 DIN ISO 11261 ISO 12099 DIN EN ISO 12099 ISO 13878 D
7、IN ISO 13878 ISO 5725-2 DIN ISO 5725-2 National Annex NA (informative) Bibliography DIN EN ISO 12099, Animal feeding stuff, cereals and milled cereal products Guidelines for the application of near infrared spectrometry DIN ISO 10694, Soil quality Determination of organic and total carbon after dry
8、combustion (elementary analysis) DIN ISO 11261, Soil quality Determination of total nitrogen Modified Kjeldahl method DIN ISO 13878, Soil quality Determination of total nitrogen content by dry combustion (“elemental analysis”) DIN ISO 5725-2, Accuracy (trueness and precision) of measurement methods
9、and results Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 17184 May 2014 ICS 13.080.10 English Version Soil quality - Determination of carbon and nitrogen by near-infrared spec
10、trometry (NIRS) (ISO 17184:2014) Qualit du sol - Dosage du carbone et de lazote par spectromtrie proche infrarouge (SPIR) (ISO 17184:2014)Bodenbeschaffenheit - Bestimmung von Kohlenstoff und Stickstoff durch Nahinfrarotspektroskopie (NIRS) This European Standard was approved by CEN on 24 April 2014.
11、 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
12、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-CENELE
13、C 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,
14、 Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue
15、 Marnix 17, B-1000 Brussels 2014 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 17184:2014 E(ISO 17184:2014) EN ISO 17184:2014 (E) 2 DIN EN ISO 17184:2014-09 Contents Page Foreword 3 1 Scope 4 2 Normative references 4 3 Princi
16、ple 4 4 Apparatus .4 5 Procedure .5 5.1 Preparation of samples .5 5.2 Instrument calibration .5 5.2.1 General 5 5.2.2 Validation of the calibration model 6 5.3 Sample measurement 7 6 Test report 8 Annex A (informative) Precision data 9 Bibliography 12 EN ISO 17184:2014 (E) 3 Foreword This document (
17、EN ISO 17184:2014) has been prepared by Technical Committee ISO/TC 190 “Soil quality” in collaboration with Technical Committee CEN/TC 345 “Characterization of soils” the secretariat of which is held by NEN. This European Standard shall be given the status of a national standard, either by publicati
18、on of an identical text or by endorsement, at the latest by November 2014, and conflicting national standards shall be withdrawn at the latest by November 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 sh
19、all 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 implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, De
20、nmark, 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. Endorsement
21、notice The text of ISO 17184:2014 has been approved by CEN as EN ISO 17184:2014 without any modification. DIN EN ISO 17184:2014-09 1 ScopeThis International Standard specifies a method for the determination of carbon and nitrogen in soils by direct measurement of sample spectra in the near-infrared
22、spectral region. The spectra are evaluated by a suitable calibration model derived from the results obtained by reference methods.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated refer
23、ences, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 11464, Soil quality Pretreatment of samples for physico-chemical analysis3 PrincipleSoil samples are measured by reflectance near-infrared (NIR) spectro
24、scopy. Diffuse reflectance NIR spectroscopy offers a non-destructive means for measurement of soil properties based on reflectance spectra of illuminated soils. Spectral data are evaluated by a suitable calibrating model derived from the measurement of a sufficient number of representative soil samp
25、les with known content of carbon and/or nitrogen determined by reference methods. Calibration equations reflect the relationship between the constituents of the sample and NIR spectral information. The soil samples and the set of calibrating samples for the NIR measurement are prepared the same way.
26、NOTE 1 NIR spectrometry is a very fast non-destructive and environmentally friendly analytical technique when compared to the standard chemical methods used as reference methods.NOTE 2 Soils generally have similar reflectance spectra in the 1 100 nm to 2 500 nm range. The absorption peaks for soils
27、in the near-infrared region are difficult to assign to specific chemical components.4 Apparatus4.1 Near-infrared instrument, based on measurement of reflectance spectra in the near-infrared region (wavelength range from 900 nm to 2 500 nm is usually applied). The instrument should be equipped with a
28、 suitable measurement cell for pulverized solid samples. The instrument should measure sufficiently large sample volume to eliminate any significant influence of inhomogeneity of the sample. The software shall allow instrument tests, calibration, sample measurement and data evaluation.Resolution of
29、the instrument should be equal to 8 nm or better.NOTE Wavelengths of spectra recorded in higher resolution may be averaged to reduce spectra noise and there is a risk of over fitting of the calibration model. Instruments with lower resolution may be used if their performance is verified for intended
30、 purposes.Soil quality Determination of carbon and nitrogen by near-infrared spectrometry (NIRS) EN ISO 17184:2014 (E)DIN EN ISO 17184:2014-09 45 Procedure5.1 Preparation of samplesSoil samples shall be prepared the same way as soils used for the instrument calibration. Any difference in sample prep
31、aration may influence the measurement. Sample preparation shall ensure a good homogenization of the sample.Sample preparation according to ISO 11464, particle size 2 mm, is generally used. Air-dried or oven-dried samples can be used for analysis. The method is not suitable for samples with water con
32、tent higher than 10 %. Oven drying is recommended for samples with high specific surface area that are susceptible to changes in water content due to fluctuations in air humidity.5.2 Instrument calibration5.2.1 GeneralA suitable set of uniformly prepared soil samples is measured by NIR spectroscopy.
33、 The spectra and the results of the content of carbon and/or nitrogen determined by a reference method are used for calculation of the calibration model. Calibration should include enough samples to cover most of the possible spectral variability encountered during routine analysis and to predict th
34、e composition of unknown samples accurately. The calibration sample set shall be selected to gain an evenly distributed coverage of the property range.The NIR spectra represent cumulative information about the chemical and physical properties of a sample. Influence of physical properties of a sample
35、 (e.g. particle size), is reduced by mathematical corrections as derivatives, standard normal variate (SNV), multiplicative scatter corrections (MSC), etc. There are several possible ways for development of calibration equations and no specific procedure can be given. The choice shall aim at minimis
36、ing the calibration error. The methods most frequently applied in the development of calibration equations are: PCR (principal component regression), PLS (partial least square regression), LWR (locally weighted regression), SMLR (stepwise multiple linear regression) and ANN (artificial neural networ
37、k regression). Among these methods, only ANN methods can give calibration for the whole concentration range for carbon and nitrogen in soils but ANN methods only apply with more than 500 calibration samples. For other statistical methods, splitting of the concentration range into two calibrations wa
38、s found to be the best solution. Removal of outliers from the calibration set usually reduces the robustness of the calibration and should be avoided.For samples from different locations and soil types, a minimum of 60 to 100 calibration samples is required. A smaller number of calibration samples c
39、an be used for sample sets with lower variability such as samples from a defined location.NOTE 1 Transformations of the reference measurements or the spectra using e.g. log or square root transformed reference measurements may help to reduce the calibration error.NOTE 2 It is possible that calibrati
40、ons developed on a certain instrument may not always be transferred directly to an identical instrument. It may be necessary to perform bias and slope adjustments to calibration equations. In many cases it is necessary to standardize the two instruments against each other before calibration equation
41、s can be transferred. Standardization procedures can be used to transfer calibrations between instruments of different types provided that samples are measured the same way and that the spectral region is identical.NOTE 3 If the reference method is unbiased and a good linear calibration model is ach
42、ieved, increasing number of calibration samples averages out errors in the reference method. Therefore, the lack of repeatability in the reference method can be compensated for by using high number of calibrating samples.EN ISO 17184:2014 (E)DIN EN ISO 17184:2014-09 55.2.2 Validation of the calibrat
43、ion model5.2.2.1 GeneralThere are two main methods for validation of the calibration model: cross (internal) validation (see 5.2.2.2), and external validation (see 5.2.2.3).Cross validation (see 5.2.2.2) is used to determine the number of factors used for PLS by determining a minimum RMSECV (root me
44、an square error of cross validation), and when not enough samples are available for external validation. The number of factors shall be as small as possible to avoid over fitting of the calibration model. An external validation (see 5.2.2.3) shall be used to determine the calibration error since cro
45、ss validations tend to underestimate the calibration error.In all cases, if a new calibration is developed on an expanded calibration set, the validation process should be repeated. The calibrations should be checked whenever any major part of the instrument (optical system, detector) has been chang
46、ed or repaired.Next to the initial validation, NIR calibrations should be validated on a regular basis against reference methods to ensure optimal performance of calibrations. The frequency of checkings depends mainly on the number of changes in the sample population. The number of samples for the c
47、ontinuous checking should be sufficient for the statistics applied. The validation exercise is valid only for the range and for the sample types used in the validation.The prediction ability of the calibration model is given by the correlation coefficient (R) and the root mean squared error of predi
48、ction (RMSEP) which is also called root mean squared error of cross validation (RMSECV) when using cross validation. These characteristics should be reported with the results. If the difference between two parallel measurements is higher than RMSECV or RMSEP, the results may not be valid and should be investigated further.5.2.2.2 Cross validationThe set of calibration data is divided into K groups, each group has n/K individual samples. One group of the K groups is retained for validation of the model and the remaining K 1 groups a
