1、BRITISH STANDARD BS 7709-1: 1993 ISO 10136-1: 1993 Analysis of extract solutions of glass Part 1: Method for determination of silicon dioxide by molecular absorption spectrometry UDC 666.11/.18.01.2:543.422:546.284-31BS7709-1:1993 This British Standard, having been prepared under the directionof the
2、 Laboratory Apparatus Standards Policy Committee, was published underthe authority of theStandards Board and comesinto effect on 15September1993 BSI 11-1999 The following BSI references relate to the work on this standard: Committee reference LBC/36 Draft for comment 90/56734 DC ISBN 0 580 22277 2 C
3、ommittees responsible for this British Standard The preparation of this British Standard was entrusted by the Laboratory Apparatus Standards Policy Committee (LBC/-) to Technical Committee LBC/36, upon which the following bodies were represented: Association for Science Education BLWA Ltd. (The Asso
4、ciation of the Laboratory Supply Industry) British Glass Manufacturers Confederation CLEAPSS School Science Service Department of Trade and Industry (Laboratory of the Government Chemist) Institute of Medical Laboratory Sciences The following body was also represented in the drafting of the standard
5、, through a subcommittee: Society of Glass Technology Amendments issued since publication Amd. No. Date CommentsBS7709-1:1993 BSI 11-1999 i Contents Page Committees responsible Inside front cover National foreword ii Introduction 1 1 Scope 1 2 Normative references 1 3 Definitions 2 4 Principle 2 5 R
6、eagents 2 6 Apparatus 3 7 Sampling and samples 3 8 Procedure 4 9 Expression of results 4 10 Test report 4 Annex A (informative) Bibliography 5 List of references Inside back coverBS7709-1:1993 ii BSI 11-1999 National foreword This Part of BS7709 has been prepared under the direction of the Laborator
7、y Apparatus Standards Policy Committee and is identical with ISO10136-1:1993 Glass and glassware Analysis of extract solutions Part 1: Determination of silicon dioxide by molecular absorption spectrometry, published by the International Organization for Standardization (ISO). ISO10136-1 has been pre
8、pared by Subcommittee5 of Technical Committee ISO/TC48, with the active participation and approval of the UK. BS7709 is published in six Parts as follows: Part 1: Method for determination of silicon dioxide by molecular absorption spectrometry; Part 2: Method for determination of sodium oxide and po
9、tassium oxide by flame spectrometric methods; Part 3: Method for determination of calcium oxide and magnesium oxide by flame atomic absorption spectrometry; Part 4: Method for determination of aluminium oxide by molecular absorption spectrometry; Part 5: Method for determination of iron(III) oxide b
10、y molecular absorption spectrometry and flame atomic absorption spectrometry; Part 6: Method for determination of boron(III) oxide by molecular absorption spectrometry. BS 2649 Methods for analysis of glass Part 1:1988 Glasses of the soda-lime-magnesia-silica type and Part 3:1988 Glasses of the pota
11、ssium oxide-lead oxide-silica type describe methods of determination primarily of the gravimetric type. The methods given in BS7709 should be considered complementary to those of BS2649. The Technical Committee has reviewed the provisions of ISO385-2, ISO648, ISO835-3, ISO6955 and ISO7056, to which
12、normative reference is made in the text, and has decided that they are acceptable for use in conjunction with this standard. Cross-references International Standard Corresponding British Standard BS 700 Graduated pipettes ISO 835-1:1981 Part 1:1982 Specification for general requirements (Identical)
13、ISO 835-2:1981 Part 2:1982 Specification for pipettes for which no waiting time is specified (Identical) ISO 1042:1983 BS 1792:1982 Specification for one-mark volumetric flasks (Identical) ISO 3585:1991 BS 2598 Glass plant, pipeline and fittings Part 1:1991 Specification for properties of borosilica
14、te glass 3.3 (Identical) ISO 3696:1987 BS 3978:1987 Specification for water for laboratory use (Identical) ISO 3819:1985 BS 6523:1984 Specification for glass beakers for laboratory use (Technically equivalent)BS7709-1:1993 BSI 11-1999 iii This British Standard describes a method of test only and sho
15、uld not be used or quoted as a specification defining limits of performance. Reference to this British Standard should indicate that the method of test used is in accordance with BS7709-1:1993. A British Standard does not purport to include all the necessary provisions of a contract. Users of Britis
16、h Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i to iv, pages1to 6, an inside back cover and a back cover. Th
17、is standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.iv blankBS7709-1:1993 BSI 11-1999 1 Introduction The determination of silica (SiO 2 ) in durability extract solutions has not, hitherto,
18、 been included in classifications of glass or glassware according to chemical resistance. Indeed, in many applications the concentrations of silica found in such extract solutions, normally very low, are not significant and are of little interest. There are occasions where such releases could be imp
19、ortant, for example from glassware used in the determination of small concentrations of silica in solutions or, in some cases, releases from medical and pharmaceutical ware. Then again, in examining the properties of new glass compositions it could be an advantage to know the full analysis of the du
20、rability extract solutions. Technical Committee2, Chemical Durability and Analysis, of the International Commission on Glass (ICG), investigated two procedures for determining silica (see6 in Annex A) by the molecular absorption spectrometric technique. Both were based on the formation of colour com
21、plexes in the presence of ammonium molybdate, one using the yellow colour of the complex formed, the other using the blue colour produced when a suitable reducing agent is added. In collaborative experimental work, twelve laboratories analysed silica in two synthetic solutions and in extract solutio
22、ns produced by the test described in ISO480234. It was agreed that whilst determinations using the yellow complex were more consistent, they were also less sensitive and, since the concentrations of silica in extract solutions are normally very low, the blue complex method was preferred. The results
23、 of investigations on turbidities, especially in grain test solutions, showed that acidification to dissolve possible hydroxides and/or carbonates is necessary prior to the analytical determination. This is achieved by using spectroscopic buffer solutions, which are normally strongly acidic, or by a
24、ddition of acids. 1 Scope This part of ISO10136 specifies an analytical procedure, using molecular absorption spectrometry, for measuring the concentrations of silicon, expressed as silicon dioxide or silica (SiO 2 ), released into extract solutions during hydrolytic resistance test procedures. This
25、 part of ISO10136 applies to the analysis of extract solutions obtained from any kind of glass or glassware, including laboratory and pharmaceutical ware made, for example, from borosilicate glass (such as borosilicate glass 3.3 according to ISO3585), neutral glass, or soda-lime-silica glass as defi
26、ned in ISO480234, food and drink packaging ware, tableware and kitchenware. The extract solution may be obtained from glass articles, for example according to ISO4802, or from glass as material, for example when tested according to ISO7191 or ISO7202. In addition, it may be applied to the extract so
27、lutions produced by any method for measuring the hydrolytic resistance of glass or glassware. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part of ISO10136. At the time of publication, the editions indicated we
28、re valid. All standards are subject to revision, and parties to agreements based on this part of ISO10136 are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International St
29、andards. ISO 385-2:1984, Laboratory glassware Burettes Part 2: Burettes for which no waiting time is specified. ISO 648:1977, Laboratory glassware One-mark pipettes. ISO 835-1:1981, Laboratory glassware Graduated pipettes Part 1: General requirements. ISO 835-2:1981, Laboratory glassware Graduated p
30、ipettes Part 2: Pipettes for which no waiting time is specified. ISO 835-3:1981, Laboratory glassware Graduated pipettes Part 3: Pipettes for which a waiting time of15s is specified. ISO 1042:1983, Laboratory glassware One-mark volumetric flasks. ISO 3585:1991, Borosilicate glass 3.3 Properties. ISO
31、 3696:1987, Water for analytical laboratory use Specification and test methods. ISO 3819:1985, Laboratory glassware Beakers. ISO 6955:1982, Analytical spectroscopic methods Flame emission, atomic absorption, and atomic fluorescence Vocabulary. ISO 7056:1981, Plastics laboratory ware Beakers. BS7709-
32、1:1993 2 BSI 11-1999 3 Definitions For the purposes of this part of ISO10136, the following definitions apply. 3.1 extract solution the aqueous solution obtained from the reaction of glass with water under specific conditions 3.2 sample measuring solution the solution actually used for measuring the
33、 concentration of the analyte. It may be the undiluted, diluted or modified extract solution 3.3 analyte the element or constituent to be determined 3.4 stock solution a solution of appropriate composition containing the analyte, expressed as its oxide, in a known but high concentration 3.5 standard
34、 solution a solution containing the analyte, expressed as its oxide, in a known concentration suitable for the preparation of reference or calibration solutions 3.6 set of calibration solutions; set of reference solutions a set of simple or synthetic reference solutions having different analyte conc
35、entrations. The zero member is, in principle, the solution having zero concentration of the analyte ISO6955 3.7 molecular absorption spectrometry (MAS) a technique for determining the concentration of an analyte in solution by measuring the optical density of a colour complex of the analyte 3.8 blan
36、k test solution a solution prepared in the same way as the sample measuring solution but so that it does not contain the analyte to be determined 4 Principle Conditioning of the extract solution to be analysed and developing of the blue silicomolybdate complex using ammonium molybdate and a reducing
37、 solution. Measurement of the optical density of the colour complex, when measuring the sample measuring solution, by means of a molecular absorption spectrometer at800nm using10mm optical cells. 5 Reagents During the analysis, unless otherwise stated, use only reagents of recognized analytical grad
38、e, and grade1 or grade2 water as specified in ISO3696. When acids and ammonium hydroxide are specified only by name or chemical formula, the concentrated reagent is intended. The concentrations of diluted acids or ammonium hydroxide are specified as a ratio, stating the number of volumes of the conc
39、entrated reagent to be added to a given number of volumes or water. For example, 1+3 means that1 volume of the concentrated reagent shall be diluted with3 volumes of water. Commercially available standard solutions for spectrometry may be used for the preparation of the stock or standard solutions.
40、5.1 4-Amino-3-hydroxynaphthalene-1-sulfonic acid or1-amino-2-hydroxynaphthalene-4-sulfonic acid NH 2 C 10 H 5 (OH)SO 3 H 5.2 Ammonium molybdate (NH 4 ) 6 Mo 7 O 24 .4H 2 O, 60g/l aqueous solution. 5.3 Boric acid (H 3 BO 3 ), 50g/l solution. 5.4 2,4-Dinitrophenol 2,4-(NO 2 ) 2 C 6 H 3 OH,1g/l indicat
41、or solution. 5.5 Hydrochloric acid (HCl), =1,19 g/ml. 5.5.1 Hydrochloric acid, diluted1+5. 5.5.2 Hydrochloric acid, diluted1+24. 5.6 Hydrofluoric acid (HF) solution, =1,13g/ml. 5.7 Reducing solution Dissolve0,7g of sodium sulfite (5.15) in20mlofwater, add0,15g of 4-amino-3-hydroxynaphthalene-1-sulfo
42、nic acid or1-amino-2-hydroxynaphthalene-4-sulfonic acid(5.1) and stir to dissolve. Dissolve9g of sodium metabisulfite (5.14) in160ml of water and transfer both solutions to the same200ml one-mark volumetric flask (6.7). Make up to the mark and mix. This solution shall be discarded if the faintest bl
43、ue coloration appears.BS7709-1:1993 BSI 11-1999 3 5.8 Silicon dioxide (also called silica) (SiO 2 ). Use finely ground silica sand containing at least99,9% (m/m) SiO 2 , dried at110 C at least. 5.9 Silica, stock solution. Weigh, to the nearest0,1mg, about1g of silica (5.8) into a platinum dish (6.6)
44、. Add4,5g of sodium carbonate (5.11) and intimately mix using a dry rod (do not use a glass rod). Ease the mixture into the centre of the dish and flatten it to cover an area of diameter about30mm. Cover the mixture as evenly as possible with a further0,5g of sodium carbonate(5.11), then gently brus
45、h any particles adhering to the rod into the dish. Cover the dish with a platinum lid (6.6) and place it in a muffle furnace at300 C to400 C. Gradually increase the temperature to1100 C and maintain this for about10min or until fusion is complete. Remove the dish from the furnace and gently swirl th
46、e melt to incorporate any remaining particles. Allow to cool, wash any material adhering to the underside of the lid into the dish using hot water, then dissolve the fused mass in hot water. Cool, transfer the solution to a1000ml one-mark volumetric flask (6.7), make up to the mark with water and mi
47、x. Transfer the solution to the plastics bottle (6.3) for storage. 1ml of this solution contains1mg of SiO 2 . 5.10 Silica, standard solution. Using a one-mark pipette (6.10), transfer10,00ml of the silica stock solution (5.9) to a1000ml one-mark volumetric flask (6.7), make up to the mark with wate
48、r and mix. This solution shall be freshly prepared immediately before use. 1ml of this standard solution contains104g of SiO 2 . 5.11 Sodium carbonate (Na 2 CO 3 ), anhydrous. 5.12 Sodium hydroxide, solution, c(NaOH) . 2mol/l, stored in a plastics bottle (6.3). 5.13 Sodium hydroxide, solution, c(NaO
49、H) . 0,1mol/l, stored in a plastics bottle (6.3). 5.14 Sodium metabisulfite (Na 2 S 2 O 5 ) 5.15 Sodium sulfite (Na 2 SO 3 ), anhydrous. 5.16 Tartaric acid (CHOHCOOH) 2 200g/l solution. 6 Apparatus Laboratory glassware, except pipettes and burettes, shall be made of borosilicate glass, preferably of type3.3 complying with the requirements in ISO3585. Ordinary laboratory apparatus, and 6.1 Molecular absorption spectrophotometer, capable of measuring optical density at800nm. 6.2 Optical cells, 10mm
