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1、INTERNATIONAL STANDARD 5440 ,NTERNAT,ONAL ORGANiZATlON FOR STANDARDIZATIONMEXJYHAPOHAR OPrAHHBAL,HR fl0 CTAHAF T113AtWlKJRGANISATlON INTERNATIONALE DE NORMALISATION 7; x.,+-i c 5 -i-, + r-y, 3 ,+.$A a, :-A gil :c ;. -4. Sodium hexafluorosilicate for industrial use - Determination of phosphate conten
2、t - Molybdovanadate spectrophotometric method Hexafluorosilicate de sodium ti usage industriel - Dosage des phosphates - Mkthode spectrophotomtitrique au molybdovanadate First edition - 1978-10-01 Gi UDC 661.488 : 546.185 : 543.42 Ref. No. IS0 5440-1978 (E) E 7 s Descriptors : chemical compounds, so
3、dium fluorosilicates, chemical analysis, determination of content, orthophosphates, spectrophoto- P metric analysis. Lo Price based on 3 Pages Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale
4、, 04/28/2007 07:51:48 MDTNo reproduction or networking permitted without license from IHS -,-,- FOREWORD IS0 (the International Organization for Standardization) is a worldwide federation of national standards institutes (IS0 member bodies). The work of developing International Standards is carried
5、out through IS0 technical committees. Every member body interested in a subject for which a technical committee has been set up has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. Draft In
6、ternational Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the IS0 Council. International Standard IS0 5440 was developed by Technical Committee lSO/TC 47, Chemistry, and was circulated to the membe
7、r bodies in July 1976. It has been approved by the member bodies of the following countries : Belgium Brazil Chile Czechoslovakia Egypt, Arab Rep. of France Germany Hungary India Israel Korea, Rep. of Mexico Netherlands Philippines Poland Romania No member body expressed disapproval of the document.
8、 South Africa, Rep. of Spain Switzerland Thailand Turkey United Kingdom U.S.S.R. Yugoslavia 0 International Organization for Standardization, 1978 l Printed in Switzerland Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standard
9、s 1/9972545001 Not for Resale, 04/28/2007 07:51:48 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD IS0 5440-1978 (E) Sodium hexafluorosilicate for industrial use - Determination of phosphate content - Molybdovanadate spectrophotometric method WARNING
10、- Sodium hexafluorosilicate is poisonous if taken internally. Breathing of the dust should be avoided. Contact with the eyes and skin should be prevented and operators should wash thoroughly after handling the material and should wear a respirator and goggles when handling the powdered material. 1 S
11、COPE AND FIELD OF APPLICATION This International Standard specifies a molybdovanadate spectrophotometric method for the determination of the phosphate content of sodium hexafluorosilicate for industrial use. The method is applicable to products having phosphate contents, expressed as P,O, of 0,005 t
12、o 0.05 % (m/m). 2 REFERENCE IS0 5444, Sodium hexafluorosilicate for industrial use - Determination of loss in mass at 105C. 3 TEST SAMPLE Use the residue from the determination of the loss in mass at 105 “C (see IS0 5444) to prepare the test sample. 4 PRINCIPLE Dissolution of a test portion in dilut
13、e hydrochloric and nitric acid solutions. Formation of the yellow molybdovanadate and spectrophotometric measurement at a wavelength of about 420 nm. Calculation of the phosphate content, expressed as P,O, from the measured absorbance. NOTE - If the molybdovanadate complex is used instead of the blu
14、e molybdate complex, it is not necessary to remove fluoro- silicate. There is consequently no need for a reduction step. 5 REAGENTS During the analysis, use only reagents of recognized analytical grade and only distilled water or water of equivalent purity. 5.1 Hydrochloric acid, p approximately 1,1
15、9 g/ml, about 38 % (m/m) solution. 5.2 Nitric acid, p approximately 1,40 g/ml, about 68 % (m/m) solution. 5.3 Ammonium molybdovanadate, nitric acid solution. Dissolve 20 g of ammonium molybdate tetrahydrate (NH,),Mo 0,.4H,O in about 500 ml of water, with heating. When dissolved, add 1 g of ammonium
16、metavanadate (NH,VO,) and allow to dissolve. Cool the solution, and add, in small portions, with swirling, 150 ml of the nitric acid solution (5.2). Cool the solution, dilute to 1 000 ml with water and mix. 5.4 Phosphate, standard solution, corresponding to 0,lO g of P,O, per litre. Weigh, to the ne
17、arest 0,001 g, I,92 g of potassium dihydrogen phosphate (KH,PO,), dissolve it in water in a 1 000 ml one-mark volumetric flask, dilute to the mark and mix. Immediately before use, transfer IO,0 ml of this solution to a 100 ml one-mark volumetric flask, dilute to the mark and mix. 1 ml of this standa
18、rd solution corresponds to 0,lO mg of P,O,. 6 APPARATUS Ordinary laboratory apparatus and 6.1 Spectrophotometer, fitted with cells of 1 cm optical path length. 7 PROCEDURE 7.1 Test portion Weigh, to the nearest 0,001 g, IO f 0,l g of the test sample, dried at 105 C (see clause 3), into a 250 ml beak
19、er. 7.2 Blank test Carry out a blank test at the same time as the determination, following the same procedure and using the same quantities of all the reagents, but omitting the test portion. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NAS
20、A Technical Standards 1/9972545001 Not for Resale, 04/28/2007 07:51:48 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO5440-1978 (E) 7.3 Preparation of the test solution Add 100 ml of water, IO ml of the hydrochloric acid solution (5.1) and 10 ml of the nitric acid solut
21、ion (5.2) to the beaker containing the test portion (7.1). Place a clock-glass on the beaker and heat for IO min to digest the test portion. Allow to cool. In the absence of insoluble material, transfer the solution quantitatively to a 250 ml one-mark volumetric flask. If any insoluble material is p
22、resent, filter it off, wash the filter repeatedly with water and collect the filtrate and washings in a 250 ml one-mark volumetric flask. Finally, dilute to the mark and mix. 7.4 Preparation of calibration graph 7.4.1 Preparation of standard calorimetric solutions for spectrophotometric measurements
23、 carried out with cells of 1 cm optical path length Into a series of eleven 100 ml one-mark volumetric flasks, place the volumes of the standard phosphate solution (5.4) shown in the following table. Standard phosphate solution (5.4) ml OX 1 .o zo 3.0 4,O 5.0 60 7,O 8.0 9.0 10.0 * Compensation solut
24、ion. Corresponding mass of P-JO5 w 0 0,lO 0.20 0,30 0,40 0.50 0,60 0.70 0.80 0.90 ItO Treat the contents of each flask as follows. Dilute to about 50 ml with water, add 2 ml of the hydrochloric acid solution (5.1) and 2 ml of the nitric acid solution (5.2). Then add 25 ml of the ammonium molybdovana
25、date solution (5.3) and mix. Dilute to the mark, mix and allow to stand for not less than 10 min. 7.4.2 Spectrophotometric measurements Carry out the spectrophotometric measurements using the spectrophotometer (6.11, at a wavelength of about 420 nm, in 1 cm cells, after having adjusted the instrumen
26、t to zero absorbance against water. 7.4.3 Plotting the graph Deduct the absorbance of the compensation solution from that of each standard calorimetric solution and plot a graph having, for example, the numbers of milligrams of P,O, contained in 100 ml of standard calorimetric solution as abscissae
27、and the corresponding values of absorbance as ordinates. 7.5 Determination 7.5.1 Colour development Place 50,O ml of the test solution (7.3) into a 100 ml one-mark volumetric flask, add 25 ml of the ammonium molybdovanadate solution (5.3), dilute to the mark, mix and allow to stand for not less than
28、 10 min. 7.5.2 Spectrophotometric measurements Carry out the spectrophotometric measurements on the test solution and on the blank test solution (7.21, after colour development, by the procedure specified in 7.4.2. 8 EXPRESSION OF RESULTS By means of the calibration graph (7.4.31, determine the mass
29、es of P,O, corresponding to the absorbances of the aliquot portions of the test and blank test solutions taken for colour development. The phosphate content, expressed as a percentage by mass of P,O, is given by the formula ml -m2 250 m, -m2 1000 m. x1oox= 2mo m. is the mass, in grams, of the test p
30、ortion (7.1); m, is the mass, in milligrams, of P,O, found in the aliquot portion of the test solution taken for colour development; m2 is the mass, in milligrams, of P,O, found in the corresponding aliquot portion of the blank test solution. 9 TEST REPORT The test report shall include the following
31、 particulars : a) an identification of the sample; b) the reference of the method used; c) the results and the method of expression used; d) any unusual features noted during the determination; e) any operation not included in this International Standard or in the International Standard to which ref
32、erence is made, or regarded as optional. 2 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/28/2007 07:51:48 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0
33、5440-1978 (E) ANNEX IS0 PUBLICATIONS RELATING TO SODIUM HEXAFLUOROSILICATE FOR INDUSTRIAL USE IS0 4281 - Free acidity and sodium hexafluorosilicate content. IS0 5440 - Determination of phosphate content - Molybdovanadate spectrophotometric method. IS0 5443 - Determination of iron content - 1 ,I 0-Ph
34、enanthroline spectrophotometric method. IS0 5444 - Determination of loss in mass at 105 “C. IS0 5915 - Determination of particle size distribution - Sieving method. 3 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/28/2007 07:51:48 MDTNo reproduction or networking permitted without license from IHS -,-,-