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1、TECHNICAL REPORT ISOITR 11905-2 First edition 1997003- 15 Water quality - Determination of nitrogen - Part 2: Determination of bound nitrogen, after combustion and oxidation to nitrogen dioxide, using chemiluminescence detection Qua/it6 de Ieau - Dosage de Iazote - Parfie 2: Dosage de Iazote lib, ap
2、r - type 2, when the subject is still under technical development or where for any other reason there is the future but not immediate possibility of an agreement on an International Standard; - type as a 3, when n Interna a technical committee tional Standard (“state has collected of the art”, for d
3、ata of a different example). kind from that which is normally published Technical Reports of types 1 and 2 are subject to review within three years of publication, to decide whether they can be transformed into International Standards. Technical Reports of type 3 do not necessarily have to be review
4、ed until the data they provide are considered to be no longer valid or useful. ISO/TR 119052, which is a Technical Report of type 2, was prepared by Technical Committee lSO/TC 147, Water quality, Subcommittee SC 2, Physical, chemical, biochemical methods. This document is being issued in the Technic
5、al Report (type 2) series of publications (according to subclause G.3.2.2 of part 1 of the ISO/IEC Directives, 1995) as a “prospective standard for provisional application” in the field of water quality because there is an urgent need for guidance on how standards in this field should be used to mee
6、t an identified need. This document is not to be regarded as an “International Standard”. It is proposed for provisional application so that information and experience of its use in practice may be gathered. Comments on the content of this document should be sent to the IS0 Central Secretariat. A re
7、view of the Technical Report (type 2) will be carried out not later than three years after its publication with the options of: extension for another three years; conversion into an International Standard; or withdrawal. 0 IS0 1997 All rights reserved. Unless otherwise specified, no part of this pub
8、lication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. International Organization for Standardization Case postale 56 l CH-1211 Geneve 20 l Switzerland Internet central iso.
9、ch x.400 c=ch; a=4OOnet; p=iso; o=isocs; s=central Printed in Switzerland ii Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 02:50:50 MDTNo reproduction or networking permitted w
10、ithout license from IHS -,-,- 0 IS0 ISO/TR 119052:1997(E) IS0 11905 consists of the following parts, under the general title Water quality - Determination of nitrogen - Part I: Method using oxidative digestion with peroxodisulfate - Part 2: Determination of bound nitrogen, after combustion and oxida
11、tion to nitrogen dioxide, using chemiluminiscence detection (Technical Report) Annexes A to D of this Technical Report are for information only. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resa
12、le, 04/21/2007 02:50:50 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO/TR 119052: 1997(E) 0 IS0 Introduction It is absolutely essential that the tests described in this Technical Report be carried out by suitably qualified staff. This Technical Report specifies a metho
13、d for the determination of bound nitrogen, after oxidation of inorganic and organic nitrogen compounds by combustion to nitric oxide and oxidation (by conversion with ozone) to electronically excited nitrogen dioxide. Quantification is carried out by chemiluminescence detection. The procedure descri
14、bed is the reference method. Whilst staying within the scope of this Technical Report, it is permissible to use such alternatives as given in annex A, provided that their performance .is equal to or better than that given in annex C, when calculated using the procedures given in IS0 5725-2, and when
15、 the comparison of performance data between this Technical Report and any alternative technique is carried out using the procedures described in IS0 2854. All references to mass concentrations of nitrogen are expressed in milligrams of nitrogen per litre of solution (i.e. mg/l). Copyright Internatio
16、nal Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 02:50:50 MDTNo reproduction or networking permitted without license from IHS -,-,- TECHNICAL REPORT o IS0 ISOflR 11905-2: 1997(E) Water quality - Dete
17、rmination of nitrogen - Part 2: Determination of bound nitrogen, after combustion and oxidation to nitrogen dioxide, using chemiluminescence detection 1 Scope This Technical Report specifies a method for the determination of nitrogen present in water in the form of free ammonia, ammonium, nitrite, n
18、itrate and organic compounds capable of conversion to nitrogen dioxide under the oxidative conditions described. Determination is carried out instrumentally using chemiluminescence detection. Dissolved nitrogen gas is not determined by this method. This method is applicable to the analysis of natura
19、l freshwater, sea water, drinking water, surface water, waste water and treated sewage effluent. 1.1 Range The concentration range of the method will depend on the injection volume used, which is instrument specific. Nitrogen can be determined in the range up to 200 mg/l. Higher concentrations can,
20、if necessary, be determined by dilution of the sample. 1.2 Limit of detection The limit of detection will depend on the instrument used. Using a suitable injection volume, the limit of detection is typically 0,5 mg/l. 2 Normative references The following standards contain provisions which, through r
21、eference in this text, constitute provisions of this Technical Report. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this Technical Report are encouraged to investigate the possibility of applying the most rec
22、ent editions of the standards indicated below. Members of IEC and IS0 maintain registers of currently valid International Standards. IS0 3696:1987, Water for analytical laboratory use - Specification and test methods. I SO 5667-3: 1994, Water quality - Sampling - Part 3: Guidance on the preservation
23、 and handling of samples. 3 Principle Oxidation of the sample containing nitrogen, by combustion in an oxygen atmosphere at 1 000 OC, to nitric oxide. Reaction with ozone to give electronically excited nitrogen dioxide (NO,*). Quantification of nitrogen concentration by chemiluminescence detection.
24、4 Reagents 4.1 General requirements During the analysis, use Grade 3 purity water as specified in IS0 3696 and only reagents of recognized analytical grade. The content of bound nitrogen in water used for the preparation of calibration solutions shall be negligibly low compared with the lowest conce
25、ntration to be determined. 1 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 02:50:50 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO/TR 119052: 199
26、7(E) 4.2 Hydrochloric acid, p = 1 ,I2 g/ml. 4.3 Nitrogen stock solution, p = 1,000 g/l. 4.3.1 Dissolve (4,717 - , + 0 001) g of ammonium (NH,),SO, previously dried at (105 t 2) “C to constant mass, in a volumetric flask of nominal capacity 1 000 ml, and dilute to volume with water. 4.3.2 Dissolve (7
27、,219 _ , + 0 001) g of potassium nitrate (KNO,) previously dried at (105 t 2) “C to constant mass, in a volumetric flask of nominal capacity 1 000 ml, and dilute to volume with water. 43.3 Mix equal volumes of the solutions prepared in 4.3.1 and 4.3.2 to produce a mixed standard solution. 4.4 Nitrog
28、en control stock solution, p = 1,000 g/l. Dissolve (5,358 _ , + 0 001) g of glycine (NH,-CH,-COOH) in a volumetric flask, of nominal capacity 1 000 ml, and dilute to volume with water. 4.5 Oxygen, 99,7 % (WV). 5 Apparatus 5.1 Apparatus for the determination of bound nitrogen by oxidation, with, for
29、example: reaction vessel, automatic sample injection device, sample homogenizing equipment, chemiluminescence detector and computing system. A manual injection system may also be used. Equipment should be checked using controlled samples according to the manufacturers instructions. 5.2 Homogenizer.
30、5.3 Filtration apparatus. 5.4 Syringes. 6 Sampling and sample preparation 6.1 When sampling, ensure that a representative sample is obtained (this is particularly important for samples containing any undissolved matter), and that the sample is not contaminated. In addition, see IS0 5667-3. 6.2 Withd
31、raw the samples in suitable containers made of glass or suitable plastics and appropriately sealed. 6.2.1 Analyse the samples as soon as possible. NOTE 1 Delay may result in the reporting of low values (especially in the case of biologically active samples). 62.2 Samples may be stabilized by the add
32、ition of hydrochloric acid (4.2) to achieve a pi-l-value of less than 2, and stored in a refrigerator at (4 t 2) “C for a period of up to 8 d. 6.2.3 If necessary, homogenize the sample using a homogenizer (5.2) so that a representative aliquot of it is obtained for the determination (see clause 7).
33、If this is impracticable, filter through a filter of nominal pore size 0,45 pm. 7 Interferences Depending on the instrument used, interferences may arise from memory effects. These may occur either in samples or standard solutions with high contents of bound nitrogen. Replicate measurements are ther
34、efore necessary and the first value should be rejected. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 02:50:50 MDTNo reproduction or networking permitted without license from I
35、HS -,-,- 0 IS0 ISOmR 119052: 1997(E) NOTE 2 Potential problems may arise with samples containing significant total organic carbon (TOC) concentrations. The analysis of samples containing large amounts of TOC will lead to the reporting of lower results for nitrogen. Suspected problems may be identifi
36、ed by determining nitrogen before and after suitable dilution, or by using standard addition techniques. Not all organic nitrogen compounds are quantitatively converted to nitrogen oxide by the oxidation procedure described, and consequently to nitrogen dioxide by the reaction with ozone. Poor recov
37、eries can occur with compounds containing either double or triple bonded nitrogen atoms. See the performance data in annexes B and C. If a homogenized sample containing suspended material produces results (obtained from replicate measurements) which deviate by more than IO %, the sample needs to be
38、filtered through a 0,45 pm filter, free of compounds containing nitrogen. In this case, only the dissolved portions of the bound nitrogen will be determined and reported. 8 Procedure 8.1 Follow the instructions of the instrument manufacturer. 8.2 Prior to the determination of bound nitrogen, ensure
39、that instrumental operational tests and the verification of the responses to blank and standard solutions are carried out within the intervals specified by the manufacturer. 83 . Adjust the instrument according to the manufacturers instructions for each series of measurements. 8.4 If an instrument i
40、s fitted with an automatic injection device (see 5.1), ensure that the sample is unlikely to cause any interference with the injection procedure by, for example, homogenizing the sample. (See also clause 7). 8.5 Inject identical volumes of blank solutions and samples into the instrument, according t
41、o the manufacturers instructions, and measure the responses obtained for each solution at least three times. 8.6 Use the mean response from at least three injections, taking into account any memory effects that are likely to occur (see clause 7). Use the calibration graph (see clause 9) to determine
42、 the concentration of bound nitrogen in the sample. 9 Establishment of the calibration curve 9.1 Use the mixed standard stock solution (see 4.3.3) to prepare calibration solutions in accordance with the range of concentrations of bound nitrogen expected in the samples to be determined. 9.2 The calib
43、ration solutions shall be used on the day of preparation only. For the concentration range of IO mg/l to 100 mg/l, proceed, for example, as follows. Into seven separate volumetric flasks of nominal capacity 100 ml, pipette 0 ml (blank); I,0 ml; 2,0 ml; 3,0 ml; 6,0 ml; 8,O ml or IO,0 ml of the mixed
44、standard solution (see 4.3.3) and dilute to volume with water. These quantities correspond to mass concentrations of nitrogen of 0 mg/l; IO,0 mg/l; 20,O mg/l; 40,O mg/l; 60,O mg/l; 80,O mg/l or 100,O mg/l, respectively. 9.3 The injection volume used for the measurement of each of these solutions sha
45、ll be identical to the injection volume used for the blank and sample measurements. 9.4 Use a coordinate system to plot the mass concentration of nitrogen in the calibration solutions (see 9.2) on the abscissa, and the response values on the ordinate, respectively. Alternatively, a handling system f
46、or laboratory data may be used. 9.5 Establish the linear regression function for the series of measurement so obtained. 96 I N1 is the response value of the sample, in instrument-related units; NO b is the response value of the blank, in instrument-related units; is the slope of the calibration grap
47、h, in instrument-related units . Iitres per milligram; f is the dilution factor, if applicable. where identical injection volumes of the samples and the calibration solutions are 12 Expression of results For a given mass concentration of bound nitrogen in a sample, report the results as follows: les
48、s than or equal to IO mg/l to the nearest 0,l mg/l; - IO mg/l to 100 mg/l to the nearest 1 mg/l; or greater than or equal to 100 mg/l to a maximum of two significant figures. 13 Test report The report shall contain the following information: a) a reference to this Technical Report; b) identity of th
49、e water sample; C) expression of the results according to clause 12; 4 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 02:50:50 MDTNo reproduction or networking permitted without license from IHS -,-,- 0