1、 Descriors: Water, quality, water anaiysia. chemimili analpis, detmirratiQn1 a? cpnteN nitrite, OIWUI$F abssrptiarr sw- troptmom by prtmxddiragi a5 desmitred! ia 7.2, twt replaang the te EN 232777 : 1993; %It: used Hydtaggljy carbonate Hydroggn carhonate Nitm Ammonium Cadmiumi zmc mm= Iron(li1ii Iro
2、oJll)i COWW Alunmiium Silica Urea Thiosulfate Thiosulfate Chlorine Chlixina Chltnamirre Chituamine roxylammanium chloride Sdium polphospkte ihexamtapbsphatei Sodium po(lFh0sptkgte ihexamataosphatete)i mN = 1,oOcu;r 0,W 0,W - 0.m 0,W - 0,01 + 0,03 i o,= 0,W - 0,01 -o,= -U,Qo - 0.22 -l,Cn - 0:m -o;= O
3、! rn -o!coJ: -o!m mh = 1Q.O -0;07, - O7 -E13 - qoz -0;13 i ,O1 + ,o6 -os - 0,m -O; om - 0;m - 0;m -0;ga - 407. - KO3 - - qoa - 482 - a,n - ($25, - 2,84 - qov- - 2.78. - EO1 - 982. -%IO- Water quality Determination of nitrite by the molecular absorption spectrometric method (IS0 6777: 1984) English v
4、ersion of DIN EN 26 777 Wasserbeschaffenheit; Bestimmung von Nitrit; spektrometrisches Verfahren (IS0 6777: 1984) DIN EN 26777 - Supersedes DIN 38405 Part 10, February 1981 edition. European Standard EN 26 777: 1992 has the status of a DIN Standard. A comma is used as the decimal marker This standar
5、d is part of the series Deutsche Einheitsverfahren zur Wasser-, Abwasser- und Schlammuntersuchung; Anionen (Gruppe D) (German standard methods for the examination of water, waste water and sludge; anions (group DI). National foreword This standard has been published in accordance with a decision tak
6、en by CEN/TC 230 to adopt, without alteration, International Standard IS0 6777 as a European Standard. The responsible German body involved in the preparation of this standard was the Normenausschu Wasserwesen (Water Practice Standards Committee). Expert assistance and specialized laboratories will
7、be required to perform the analysis described in this standard. Depending on the objective of the analysis, a check shall be made in each individual case on whether and to what extent additional boundary conditions will have to be specified. NOTE: Standard methods published as DIN Standards are obta
8、inable from Beuth Verlag GmbH, either individ- ually or grouped in volumes. The standard methods included in the loose-leaf publication entitled Deutsche Einheitsverfahren zur Wasser-, Abwasser- und Schlammuntersuchung will continue to be published by VCH Verlagsgesellschaft, Weinheim. The standard
9、methods relating to the Wasserhaushaltsgesefz (German Water Management Act) itself and all the regulations on waste water that have been issued to date are included in DIN-Taschenbuch (DIN Handbook) 230. Standard methods or drafl standards bearing the group title German standard methods for the exam
10、ination of water, waste water and sludge are classified under the following categories (main titles): General information (group A) (DIN 38402) Physical and physicochemical parameters (group C) (DIN 38404) Anions (group D) (DIN 38405) Cations (group E) (DIN 38406) Substance group analysis (group F)
11、(DIN 38407) Gaseous constituents (group G) (DIN 38408) Parameters characterizing effects and substances (group H) (DIN 38409) Biological-ecological methods of analysis (group M) (DIN 38410) Microbiological methods (group K) (DIN 3841 1) Bio-assays (group L) (DIN 38412) Individual constituents (group
12、 P) (DIN 38413) Sludge and sediments (group S) (DIN 38414) Bio-assays with microorganisms (group T) (DIN 38415) Information on Parts of these standards that have already been published can be obtained from the offices of the Normen- ausschu Wassewesen, telephone (030) 26 01-24 23, or from Beuth Verl
13、ag GmbH, D-10772 Berlin. Continued overleaf. EN comprises 7 pages. Beorb Verlag GmbH, Berlin, has the exclusive right of sale for German Standards (DIN-Normen). DIN EN 26 777 Engl. Price group 7 Sales No. 1107 09.93 Page 2 DIN EN 26 777: 1993 Previous edition DIN 38405 Part 10: 02.81. Amendments In
14、comparison with DIN 38405 Part 10, February 1981 edition, details of the method (sampling, apparatus and procedure) have been changed. International Patent Classification G O1 N 33/18 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 26 777 January 1993 UDC 628.1 /.3 : 620.1 : 543.3 : 543.42 : 54
15、6.173 Descriptors: Water, quality, water analysis, chemical analysis, determination of content, nitrite, molecular absorption spec- trophotometry. English version Water quality Determination of nitrite Molecular absorption spectrometric method (IS0 6777: 1984) Qualit de leau; dosage des nitrites; mt
16、hode par spectromtrie dabsorption molculaire (IS0 6777: 1984) Wasserbeschaffenheit; Bestimmung von Nitrit; spektrometrisches Verfahren (IS0 6777: 1984) This European Standard was approved by CEN on 1993-01 -20 and is identical to the IS0 Standard as referred to. CEN members are bound to comply with
17、the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national stand- ard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretari
18、at or to any CEN member. This European Standard exists in three official versions (English, French, German). A ver- sion in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officia
19、l versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Nor
20、malisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels O 1993. Copyright reserved to all GEN members. Ref. No. EN 26777:1993 E Page 2 EN 26 777: 1993 Foreword This European Standard is the endorsement of International Standard IS0 6777: 1984. Endorsement o
21、f IS0 6777 was recommended by CEN/Technical Committee 230 Water analysis under whose competence this European Standard will henceforth fall. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, and conflicting national
22、 standards withdrawn, by July 1993 at the latest. In accordance with the CENICENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Por
23、tugal, Spain, Sweden, Switzerland and United Kingdom. Water quality: determination of nitrite: molecular absorption spectrometric method Endorsement notice The text of the International Standard IS0 67771984 was approved by CEN as a European Standard without any modifi- cation. 1 Scope Page 3 EN 26
24、777: 1993 3 Principle This International Standard specifies a molecular absorption spectrometric method for the determination of nitrite in potable, raw and waste water. 2 Field of application 2.1 Range A nitrite nitrogen concentration, N, of up to 0.25 mg/i can be determined when using the maximum
25、volume (40 mi) of test portion. 2.2 Limit of detection 11 When using cells of optical path length 40 mm and a test por- tion of 40 mi, the limit of detection has been determined to lie within the range eN = 0.001 to 0,002 mg/l. 2.3 Sensitivity 1) Using a 40 mi test portion and a cell of optical path
26、 length 40mm, = 0,062 mg/l gives an absorbance of about O,= units. Using a 40 ml test portion and a cell of optical path length 10 mm, N = 0,25 mg/l gives an abcorbance of about 0.67 units. 2.4 Interferences If the alkalinity of the sample is high, some interference may be encountered (see clause 9)
27、. A range of substances often encountered in water samples has been tested for possible interference. Full details are given in the annex. Of the substances tested, only chloramine, chlorine, thiosulfate, sodium polyphosphate and iron(1ll) interfere significantly. Reaction of nitrite in the test por
28、tion with Caminobenzene sulfonamide reagent in the presence of orthophosphoric acid at pH 1,s to form a diazonium salt which forms a pink-coloured dye with N-(1-naphthyl)-1,Z-diaminoethane dihydrochloride (added with the 4-aminobenzene sulfonamide reagent). Measurement of the absorbance at 540 nrn.
29、4 Reagents During the analysis, use only reagents of recognized analytical grade and only distilled water or water of equivalent pur. 4.1 (e = 1,70g/ml). Orthophosphoric acid, 15 mol/ solution, 4.2 Orthophosphoric acid, approximately 1.5 mol/l solu- tion. Add, by means of a pipette, 25 ml of the ort
30、hophosphoric acid (4.1) to 150 f 25 ml of water. Mix and cool to room temperature. Transfer the solution to a 250 ml one-mark volumetric flask and dilute to the mark with water. Store in an amber.glass bottle. The solution is stable for at least 6 months. 4.3 Colour reagent. WARNING - This reagent i
31、s hazardous. Skin contact or ingestion of it or its ingredients must be avoided. Dissolve 4,O i 0,5 g of 4-aminobenzene sulfonamide (NH2C6H,S02NH,) in a mixture af 100 f 1 ml of the or- thophosphoric acid (4.11 and 500 I 50 ml of water in a beaker. Dissolve 2,OO f O,M g of N-( l-naphthyli-1,2-diamin
32、oethane dihydrochloride (C,HTNH-CHTCH2-NHz2HCI) in the resulting solution. Transfer to a 1 o00 ml one-mark volumetric flask and dilute to the mark with water. Mix well. Store in an amber glass bottle. The solution is stable for 1 month if stored at 2 to 5 OC. 1) Information derived from a United Kin
33、gdom interlaboratory trial involving five participants. Page 4 EN 26 777: 1993 4.4 Nitrite, standard solution, N = 100 q/i. Dissolve 0.492 2 I 0,OOO 2 g of sodium nitrite (dried at 105 OC for at least 2 h) in about 750 ml of water. Transfer quantitatively to a 1 o00 ml one-mark volumetric flask and
34、dilute to the mark with water. Store in a stoppered amber glass bottle at 2 to 5 OC. This solu- tion is stable for at least 1 month. (See clause 10.1 4.5 Nitrite, standard solution, N = 1.00 mg/l. Transfer, by means of a pipette, 10 ml of the standard nitrite solution (4.4) to a 1 o00 ml onemark vol
35、umetric flask and dilute to the mark with water. Prepare this solution each day as required, and discard after Use. 5 Apparatus All glassware shall be carefully cleaned using approximately 2 mol/l hydrochloric acid and then rinsed thoroughly with water. Ordinary laboratory apparatus, and Spectromete
36、r. suitable for measurements at a wavelength of 540 nm, together with cells of optical path length between 10 and 50 mm. 6 Sampling and samples Laboratory samples should be collected in glass bottles and should be analysed as soon as possible within 24 h of collec- tion. Storage of the samples at 2
37、to 5 OC may preserve many types of sample, but this should be verified. 7 Procedure 7.1 Test portion The maximum volume of test portion is 40 mi. This is suitable for the determination of nitrite concentrations of up to e, = 0,25 mg/l. Smaller test portions may be used as ap- propriate in order to a
38、ccommodate much higher nitrite concen- trations. If the laboratory sample contains suspended matter, this should be allowed to settle, or the sample should be filtered through a glass fibre paper before taking the test portion. 7.2 Determination Transfer, by means of a pipette, the selected volume o
39、f test portion to a 50 ml one-mark volumetric flask, and, if necessary, dilute, to 40 I 2 ml with water. I NOTE - It is always essential to adjust the volume to 40 i 2 ml to en- sure that the correct pH is obtained (after addition of the reagent) for the reaction. Add, by means of a pipette, 1 ,O ml
40、 of the colour reagent (4.3). Mix immediately by swirling and dilute to the mark with water. Mix and allow to stand. The pH at this stage should be 1,9 i 0,l. (See clause9.) At least 20 min after addition of the reagent, measure the ab- sorbance of the solution at the wavelength of maximum absor- ba
41、nce, approximately 540 nm, in a cell of suitable optical path length, using water as the reference liquid. NOTE - The wavelength of maximum absorbance should be checked when this method is first used, and should be used in all subsequent determinations. 7.3 Correction for colour If the colour of the
42、 test portion is such that it may interfere with the measurement of abcorbance, treat a duplicate test portion as described in 7.2, but replacing the colour reagent (4.3) with 1,0 ml of the orthophosphoric acid solution (4.2). 7.4 Blank test Carry out a blank test by proceeding as described in 7.2,
43、but replacing the test portion with 40 I 2 ml of water. 7.5 Preparation of the calibration graph Place, by means of a burette, into a series of nine 50 ml one mark volumetric flasks, the volumes of the standard nitrite solu- tion (4.5) shown in table 1. Dilute the contents of each flask with water t
44、o give a volume of 40 I 2 mi and proceed as described in 7.2, from the second paragraph to the end, using cells of optical path length specified in table 1. Subtract the absorbance of the zero term from the absorbances obtained for the other standard solutions and plot a graph of absorbance against
45、the mass of nitrite, as nitrogen, for each optical path length. The graph should be linear and should pass through the origin. 8 Expression of results 8.1 Method of calculation The corrected absorbance, A, of the test solution is given by the equation A, = A, - Ab or, if correction for colour was ma
46、de, by means of the equation A, = A, - Ab - A, where A, is the absorbance, as measured, of the test solution; A, is the absorbance of the blank test sdution; A, is the absorbance of the solution prepared for the cor- rection for colour. Page 5 EN 26 777: 1993 ml 0,OO 0.50 1.00 1,50 2300 z50 5.00 7s
47、10,w NOTE - It is essential that the values of A, A, and A, are measured in cells of the same optical path length for a particular sample. lis mm 0.00 10 and W 0.50 40 1,00 10 and 40 1.50 40 2m 40 2.50 10 and 40 5m 10 7.50 10 10,00 10 From the corrected absorbance A, determine from the calibra- tion
48、 graph (7.51, for the appropriate optical path length of the cell, the corresponding mass of nitfie, as nitrogen, in micrograms. The nitrite content, expressed in milligrams of nitrogen per litre, is given by the formula where mN is the mass, in micrograms, of nitrite nitrogen cor- responding to the
49、 corrected absorbance (Ar); Y is the volume, in millilitres, of the test portion. The result may be expressed as the mass concentration of nitrogen, N, or nitrite, e#% in milligrams per litre, or as the amount of substance concentration of nitrite ion, CANO;), in micromoles per litre. The appropriate conversion factors are given in table 2. Table 2 QNo; = 1 mgll 0.304 21.7 dNO$ = 1 pmol/l 0,014 0.046 Emple: A nitrogen concentration of 1 mg/l corresponds to a nitrite concentration of 3.29 mgil. 8.2 Pr
