1、BRITISH STANDARD BS 7709-3: 1993 ISO 10136-3: 1993 Analysis of extract solutions of glass Part 3: Method for determination of calcium oxide and magnesium oxide by flame atomic absorption spectrometry UDC 666.11/.18.01.2:543.422:546.414.46-31BS7709-3:1993 This British Standard, having been prepared u
2、nder the directionof the Laboratory Apparatus Standards Policy Committee, was published underthe authority of the Standards Board and comes intoeffect on 15 September 1993 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference LBC/36 Draft for comment 90/56
3、736 DC ISBN 0 580 22284 5 Committees 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 E
4、ducation BLWA Ltd. (The Association 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
5、the drafting of the standard, through a subcommittee: Society of Glass Technology Amendments issued since publication Amd. No. Date CommentsBS7709-3:1993 BSI 10-1999 i Contents Page Committees responsible Inside front cover National foreword ii Introduction 1 1 Scope 1 2 Normative references 1 3 Def
6、initions 2 4 Principle 2 5 Reagents 2 6 Apparatus 3 7 Sampling and samples 3 8 Procedure 3 9 Expression of results 5 10 Test report 5 Annex A (informative) Bibliography 6 Table 1 Parameters for the measurements of (Ca) and (Mg) 4 List of references Inside back coverBS7709-3:1993 ii BSI 10-1999 Natio
7、nal foreword This Part of BS7709 has been prepared under the direction of the Laboratory Apparatus Standards Policy Committee and is identical with ISO10136-3:1993 Glass and glassware Analysis of extract solutions Part 3: Determination of calcium oxide and magnesium, oxide by flame atomic absorption
8、 spectrometry, published by the International Organization for Standardization (ISO). ISO10136-3 has been prepared by Subcommittee5 of Technical Committee ISO/TC48, with the active participation and approval of the UK. BS 7709 is published in six Parts as follows: Part 1: Method for determination of
9、 silicon dioxide by molecular absorption spectrometry; Part 2: Method for determination of sodium oxide and potassium 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
10、of aluminium oxide by molecular absorption spectrometry; Part 5: Method for determination of iron(III) oxide by 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 a
11、nalysis of glass Part 1:1988 Glasses of the soda-lime-magnesia-silica type and Part 3:1988 Glasses of the potassium 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
12、 Technical Committee has reviewed the provisions of ISO385-2, ISO648, ISO835-3 and ISO6955, to which 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 ISO
13、 835-1:1981 BS 700 Graduated pipettes Part 1:1982 Specification for general requirements (Identical) 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 3585:1
14、991 BS 2598 Glass plant, pipeline and fittings Part 1:1991 Specification for properties of borosilicate 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 e
15、quivalent)BS7709-3:1993 BSI 10-1999 iii This British Standard describes a method of test only and should 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 BS7709-3:1993. A Bri
16、tish Standard does not purport to include all the necessary provisions of a contract. Users of British 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 fro
17、nt cover, an inside front cover, pages i to iv, pages 1 to 6, an inside back cover and a back cover. This 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 blankBS7709-3:1993 BSI 10-1999
18、 1 Introduction Classifications of glass or glassware, in National or International Standards and in the various pharmacopoeia, have relied for many years on a titration of extract solutions with a diluted mineral acid. Such solutions may contain not only the alkali metal oxides (sodium and potassiu
19、m), but also the alkaline earth oxides (calcium and magnesium), which are also titrated by acid. Thus, the determination is actually of the total alkalinity of the extract solution, although this is sometimes calculated as the equivalent mass of sodium oxide. In recent years, with the advent of more
20、 modern techniques, such as flame atomic absorption spectrometry, there has been a move towards a more complete analysis of extract solutions and a measurement of the concentrations of the separate elements present. Technical Committee 2, Chemical Durability and Analysis, of the International Commis
21、sion on Glass (ICG), investigated colorimetric methods for determining calcium and magnesium (see 5 inAnnex A) but concluded that none was particularly suitable for the determination of the very low concentrations normally found in extract solutions. In round-robin studies involving ten laboratories
22、, a procedure using flame atomic absorption spectrometry was devised and recommended for analysing extract solutions. The results of investigations on turbidities, especially in grain test solutions, showed that acidification to dissolve possible hydroxides and/or carbonates is necessary prior to th
23、e analytical determination. This is achieved by using spectroscopic buffer solutions, which are normally strongly acidic, or by addition of acids. 1 Scope This part of ISO10136 specifies the analytical procedure, using flame atomic absorption spectrometry, for measuring the concentrations of calcium
24、 and magnesium, expressed as their oxides (CaO and MgO), released into extract solutions during hydrolytic resistance test procedures. This part of ISO10136 applies to the analysis of extract solutions obtained from any kind of glass or glassware, including laboratory and pharmaceutical ware made, f
25、or example, from borosilicate glass (such as borosilicate glass3.3 according to ISO3585), neutral glass, or soda-lime-silica glass as defined in ISO480234, food and drink packaging ware, tableware and kitchenware. The extract solution may be obtained from glass articles, for example according to ISO
26、4802, or from glass as material, for example when tested according to ISO7191 or ISO7202. In addition, it may be applied to the extract solutions produced by any method for measuring the hydrolytic resistance of glass or glassware. 2 Normative references The following standards contain provisions wh
27、ich, through reference in this text, constitute provisions of this part of ISO10136. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this part of ISO10136 are encouraged to investigate the possibility of applyin
28、g the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 385-2:1984, Laboratory glassware Burettes Part 2: Burettes for which no waiting time is specified. ISO 648:1977, Laboratory glassware One-mark pipett
29、es. ISO 835-1:1981, Laboratory glassware Graduated pipettes Part 1: General requirements. ISO 835-2:1981, Laboratory glassware Graduated pipettes 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
30、 of 15s is specified. ISO 1042:1983, Laboratory glassware One-mark volumetric flasks. ISO 3585:1991, Borosilicate glass3.3 Properties. ISO 3696:1987, Water for analytical laboratory use Specification and test methods. ISO 3819:1985, Laboratory glassware Beakers. ISO 6955:1982, Analytical spectroscop
31、ic methods Flame emission, atomic absorption, and atomic fluorescence Vocabulary. BS7709-3:1993 2 BSI 10-1999 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 speci
32、fic conditions 3.2 sample measuring solution the solution actually used for measuring the 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 conta
33、ining the analyte, expressed as its oxide, in a known but high concentration 3.5 standard 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
34、 solutions a set of simple or synthetic reference solutions having different analyte concentrations. The zero member is, in principle, the solution having zero concentration of the analyte ISO 6955 3.7 flame atomic absorption spectrometry (FAAS) a technique for determining the concentration of chemi
35、cal elements based on the measurement of the absorption of characteristic electromagnetic radiation in a vapour phase in a flame 3.8 spectrochemical buffer solution a solution of a substance or substances added to the sample measuring solution and to the reference solutions in order to reduce interf
36、erences during flame spectrometric measurements 3.9 optimum working range the range of concentrations of an analyte in solution over which the relationship between absorption (or emission) and concentration is linear 3.10 blank test solution a solution prepared in the same way as the sample measurin
37、g solution but so that it does not contain the analyte to be determined 4 Principle Atomizing of the extract solution to be analysed in the flame of an air/acetylene or dinitrogen monoxide/acetylene burner through which is passed the characteristics light emitted by a calcium or magnesium hollow cat
38、hode lamp. Measurement of the portion of the 422,7nm line absorbed by calcium atoms and of the285,2nm line absorbed by magnesium atoms using a flame atomic absorption spectrometer, and comparison with the absorption produced by reference solutions of known calcium and magnesium concentrations atomiz
39、ed under the same conditions. 5 Reagents During the analysis, unless otherwise stated, use only reagents of recognized analytical grade, and grade 1 or grade 2 water as specified in ISO3696. When acids and ammonium hydroxide are specified only by name or chemical formula, the concentrated reagent is
40、 intended. The concentrations of diluted acids or ammonium hydroxide are specified as a ratio, stating the number of volumes of the concentrated 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 with 3 volume
41、s of water. Commercially available standard solutions for spectrometry may be used for the preparation of stock or standard solutions. 5.1 Calcium carbonate (CaCO 3 ), dried at 110 C (at least) and stored in a desiccator. 5.2 Calcium oxide, stock solution. Weigh, to the nearest 0,1mg, 1,7858g of cal
42、cium carbonate (5.1) and transfer to a150ml dish. Cover with a watch glass and carefully add 100ml of hydrochloric acid (5.5) to dissolve. Heat almost to boiling until all the gas has been evolved, rinse the underside of the watch glass into the solution, cool and transfer the solution to a 1000ml o
43、ne-mark volumetric flask (6.4). Make up to the mark with water and mix. Transfer to a 1000ml stoppered bottle (6.3) for storage. 1ml of this stock solution contains1mg of CaO.BS7709-3:1993 BSI 10-1999 3 5.3 Calcium oxide, standard solution. Using a one-mark pipette (6.6), transfer 25ml of the calciu
44、m oxide stock solution (5.2) to a250ml one-mark volumetric flask (6.4), make up to the mark with water and mix. Transfer to a250ml stoppered bottle (6.3) for storage. This solution shall be freshly prepared immediately before use. 1ml of this standard solution contains 1004g ofCaO. 5.4 Hydrochloric
45、acid (HCl), = 1,19g/ml. 5.5 Hydrochloric acid, diluted 1 + 12. 5.6 Magnesium oxide (MgO), ignited at 1050 C for1h and allowed to cool in a desiccator. 5.7 Magnesium oxide, stock solution. Weigh, to the nearest0,1mg, 0,1000g of magnesium oxide (5.6) and transfer it to a250ml beaker (6.2). Add70ml of
46、hydrochloric acid (5.5) and heat, if necessary, to dissolve. Cool the solution, then transfer it to a 1000ml one-mark volumetric flask (6.4), make up to the mark with water and mix. Transfer to a 1000ml stoppered bottle (6.3) for storage. Discard after1month. 1ml of this stock solution contains 1004
47、g of MgO. 5.8 Magnesium oxide, standard solution. Using a one-mark pipette (6.6), transfer25ml of the magnesium oxide stock solution (5.7) to a250ml one-mark volumetric flask (6.4), make up to the mark with water and mix. Transfer to a250ml stoppered bottle (6.3) for storage. This solution shall be
48、freshly prepared immediately before use. 1ml of this standard solution contains 104g of MgO. 5.9 Lanthanum oxide (La 2 O 3 ). 5.10 Spectrochemical buffer solution Transfer 11,7g of lanthanium oxide (5.9) to a250ml beaker (6.2), add 100ml of hydrochloric acid(5.4) and dissolve while heating gently. C
49、ool, transfer to a 1000ml one-mark volumetric flask(6.4), make up to the mark with water and mix. 6 Apparatus All 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 Flame atomic absorption spectrometer, equipped with line sources for calcium (422,7nm) and magnesium (285,2nm) and with gas supplies and burners for air/acetylene or dinitrogen monoxide/acetylene gas mix
