BS ISO 11041-1997 Workplace air - Determination of particulate arsenic and arsenic compounds and arsenic trioxide vapour - Method by hydride generation and atomic absorption spectr.pdf

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1、BRITISH STANDARD BS ISO 11041:1996 Implementation of ISO 11041:1996 Workplace air Determination of particulate arsenic and arsenic compounds and arsenic trioxide vapour Method by hydride generation and atomic absorption spectrometry ICS 13.040.30BS ISO 11041:1996 This British Standard, having been p

2、repared under the direction of the Health and Environment Sector Board, was published under the authority of the Standards Board and comes into effect on 15 January 1997 BSI 12-1998 The following BSI references relate to the work on this standard: Commitee reference EH/2/2 Draft for comment 94/50311

3、1 DC ISBN 0 580 26877 2 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee EH/2, Air quality, to Subcommittee EH/2/2, Workplace atmospheres, upon which the following bodies were represented: Asbestos Information Centre Limit

4、ed Asbestosis Research Council BCIRA British Ceramic Research Limited British Gas plc British Occupational Hygiene Society Chemical Industries Association Department of Trade and Industry (Laboratory of the Government Chemist) Employers Association of Catering Equipment Engineers Limited Engineering

5、 Equipment and Materials Users Association Fibre Cement Manufacturers Association Limited Health and Safety Executive Institute of Energy Institution of Occupational Hygienists Institute of Occupational Medicine London Transport Royal Society of Chemistry Amendments issued since publication Amd. No.

6、 Date CommentsBSISO11041:1996 BSI 12-1998 i Contents Page Committees responsible Inside front cover National foreword ii Foreword iii Text of ISO 11041 1BS ISO 11041:1996 ii BSI 12-1998 National foreword This British Standard reproduces verbatim ISO11041:1996 and implements it as the UK national sta

7、ndard. This British Standard is published under the direction of the Health and Environment Sector Board whose Technical Committee EH/2 has the responsibility to: aid enquirers to understand the text; present to the responsible international committee any enquiries on interpretation, or proposals fo

8、r change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK. NOTEInternational and European Standards, as well as overseas standards, are available from Customer Services, BSI,389 Chiswick High Road, London W44AL. Textual errors Whe

9、n adopting the text of the international standard, the textual errors listed below were discovered. They have been marked in the text and have been reported to ISO in a proposal to amend the text of the international standard. 1. 8.2.2 “cover with a watch” should read “cover with a watch glass”. 2.

10、8.2.3 The word “NOTE” should precede “34 The solutions”. 3. 8.4.1 The word “NOTE” should precede “38 The 193,7 nm arsenic line”, and the text should read “but the use of the latter” and not “but its use”, for clarity. A British Standard does not purport to include all the necessary provisions of a c

11、ontract. 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 front cover, an inside front cover, pages i and ii, theISOtitle page, pages ii t

12、o iv, page 1 to 18, an inside back cover and abackcover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on theinside front cover.BSISO11041:1996 ii BSI 12-1998 Contents Page Foreword iii 1 Scope 1 2 Normativ

13、e references 1 3 Principle 1 4 Reactions 2 5 Reagents 2 6 Apparatus 4 7 Sampling 7 8 Procedure for analysis 11 9 Expression of results 15 10 Special cases 17 11 Test report 18 Annex A (informative) Bibliography Inside back cover Figure 1 Schematic example of a configuration of a continuous-flow hydr

14、ide generation system 8 Figure 2 Schematic example of a configuration of a flow-injection-analysis hydride generation system 9BS ISO 11041:1996 BSI 12-1998 iii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies)

15、. The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non

16、-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies

17、for voting. Publication as an International Standard requires approval by at least75% of the member bodies casting a vote. International Standard ISO11041 was prepared by Technical Committee ISO/TC146, Air quality, Subcommittee SC2, Workplace atmospheres. Annex A of this International Standard is fo

18、r information only.iv blankBS ISO 11041:1996 BSI 12-1998 1 WARNING Arsenic and arsenic compounds are toxic and are recognized as human carcinogens (see reference 1 in annex A). Avoid any exposure by inhalation. Personal protection (e.g. an effective respirator) must be used in all cases where exposu

19、re to arsenic or arsenic compounds is possible. 1 Scope This International Standard specifies a method for the determination of the mass concentration of particulate arsenic and arsenic compounds and arsenic trioxide vapour in workplace air, using either continuous-flow hydride generation or flow-in

20、jection-analysis hydride generation and atomic absorption spectrometry. The method is not suitable for determination of arsenic in the form of metal arsenides which decompose in the presence of water or acid (see10.1). The method is applicable to the determination of masses of approximately100ng to1

21、25g of arsenic per sample, for analysis of test solutions prepared using sample solution aliquots in the recommended range (see9.3.2). The concentration range for arsenic in air, for which this procedure is applicable, is determined in part by the sampling procedure selected by the user. The method

22、is applicable to personal and fixed-location sampling. A number of transition metals may interfere with the determination of arsenic by hydride generation and atomic absorption spectrometry (see10.3) 2 Normative references The following standards contain provisions which, through reference in this t

23、ext, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent ed

24、itions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 648:1977, Laboratory glassware One-mark pipettes. ISO 1042:1983, Laboratory glassware One-mark volumetric flasks. ISO 3585:1991, Borosilicate glass3.3 Properties. ISO 36

25、96:1987, Water for analytical laboratory use Specification and test methods. ISO 6955:1982, Analytical spectroscopic methods Flame emission, atomic absorption and atomic fluorescence Vocabulary. ISO 7708:1995, Air quality Particle size fraction definitions for health-related sampling. ISO 8655-1: 1)

26、 , Piston and/or plunger operated volumetric apparatus (POVA) Part1: Definitions. ISO 8655-2: 1) , Piston and/or plunger operated volumetric apparatus (POVA) Part2: Operating considerations. ISO 8655-3: 1) , Piston and/or plunger operated volumetric apparatus (POVA) Part3: Methods of test. ISO 8655-

27、4: 1) , Piston and/or plunger operated volumetric apparatus (POVA) Part4:Specifications. ISO8756:1994, Air quality Handling of temperature, pressure and humidity data. EN482:1994, Workplace atmospheres General requirements for the performance of procedures for the measurement of chemical agents. EN4

28、82, CEN, Brussels, Belgium (1994). EN 1232: 1) , Workplace atmospheres Pumps for personal sampling of chemical agents Requirements and test methods. 3 Principle 3.1 Particulate arsenic and arsenic compounds and arsenic trioxide vapour are collected by drawing a measured volume of air through a cellu

29、lose ester membrane filter and a back-up paper pad impregnated with sodium carbonate and mounted in a sampler designed to collect the inhalable fraction of airborne particles. 3.2 The cellulose ester membrane filter, back-up paper pad and collected sample are wet-ashed using nitric acid, sulfuric ac

30、id and hydrogen peroxide. The nitric acid and hydrogen peroxide are removed by boiling on a hotplate until dense, white fumes of sulfur trioxide are evolved, and the sample solution is then allowed to cool and diluted to a given volume with water. NOTE1The wet-ashing procedure specified in8.2.2 is b

31、ased upon a NIOSH procedure (see reference 2 in annex A) which has been modified to avoid taking the sample solution to dryness. 3.3 A test solution is prepared by transferring an aliquot of the sample solution to a volumetric flask, together with appropriate volumes of dilute sulfuric acid, concent

32、rated hydrochloric acid and potassium iodide solution, and diluting to volume with water. 1) To be publishedBS ISO 11041:1996 2 BSI 12-1998 3.4 The test solution is reacted with sodium tetrahydroborate solution in a continuous-flow hydride generation system or flow-injection-analysis hydride generat

33、ion system to liberate arsine and hydrogen. These gaseous products are separated from the reaction liquid in a gas/liquid separator and carried by an inert purge gas into a silica or quartz absorption cell. This absorption cell is mounted in the optical path of an atomic absorption spectrometer equi

34、pped with an arsenic hollow cathode lamp or electrodeless discharge lamp, and it is heated either electrically or by an oxidizing air/acetylene flame. NOTE2This International Standard describes the use of two types of hydride generation system. Continuous flow systems function by pumping a continuou

35、s stream of test solution to the mixing piece, and such systems generate a constant atomic absorption signal. Flow injection analysis systems inject a discrete volume of test solution, and produce a transient atomic absorption signal. 3.5 Absorbance measurements are made at197,2nm or193,7nm, and res

36、ults are obtained by the analytical-curve technique (seeISO6955:1982, subclause 6.1.1), or the analyte addition technique (seeISO6955:1982, subclause6.1.3). 4 Reactions 4.1 In most workplace situations where exposure to arsenic can occur (e.g. in the refining of base metals, welding and other hot me

37、tal processes) a significant proportion of the arsenic is present in the form of arsenic trioxide vapour (see reference 3 in annexA). This vapour is collected by reaction with sodium carbonate on an impregnated back-up paper pad. As 2 O 3+ Na 2 CO 3 2NaAsO 2+ CO 2 4.2 The majority of arsenic compoun

38、ds which are commonly found in samples of workplace air are converted to soluble arsenate ions (AsO 4 3 ) by the wet-ashing procedure specified in 8.2.2. However, if there is any doubt about the effectiveness of this procedure for dissolution of particulate arsenic compounds which could be present i

39、n the test atmosphere, investigate before proceeding with the method (see10.2). 4.3 Prior to hydride generation (see4.4) arsenate ions (AsO 4 3 ) are reduced to arsenite ions (AsO 2 ) by reaction with potassium iodide (see8.2.4). AsO 4 3+ 2l + 4H + AsO 2 + l 2+ 2H 2 O This reduction is necessary sin

40、ce pentavalent arsenic gives a lower analytical response than trivalent arsenic because it is less rapidly converted to arsine. 4.4 Hydride generation occurs as a result of the reaction between trivalent arsenic and nascent hydrogen produced by the action of hydrochloric acid on sodium tetrahydrobor

41、ate solution. 4.5 Arsenic atoms are produced from arsine by the action of heat in a silica or quartz absorption cell, heated either by a lean air/acetylene flame or electrically. 5 Reagents During the analysis, use only reagents of analytical grade, and only water as specified in 5.1. 5.1 Water, com

42、plying with the requirements for ISO3696 grade 2 water (electrical conductivity less than0,1mS/m and resistivity greater than0,01MWm at 25 C). 5.2 Sodium carbonate,1mol/l solution in 5 % (V/V) glycerol solution. Weigh 10,6 g of sodium carbonate (Na 2 CO 3 ) into a250ml beaker (6.2.1.1). Add5ml of gl

43、ycerol and50ml of water (5.1) and swirl to dissolve. Quantitatively transfer the solution to a100ml one-mark volumetric flask (6.2.1.5), dilute to the mark with water, stopper and mix thoroughly. 5.3 Hydrochloric acid (HCl), concentrated r 1,18g/ml, 35 % (m/m) to 36 % (m/m). The concentration of ars

44、enic shall be less than0,01g/ml. WARNING Concentrated hydrochloric acid is corrosive, and hydrochloric acid vapour is irritant. Avoid exposure by contact with the skin or eyes, or by inhalation of fumes. Personal protective equipment (e.g. gloves, face shield or safety spectacles, etc.) must be used

45、 when working with the concentrated or diluted hydrochloric acid, and concentrated hydrochloric acid must be used in a fume hood. The vapour pressure of hydrochloric is high, therefore beware of pressure build-up in stoppered flasks when preparing acid/water mixtures. 5.4 Hydrochloric acid, diluted

46、1 + 1. Pour approximately900ml of water (5.1) into a2000 ml one-mark volumetric flask (6.2.1.5). Carefully add1000 ml of concentrated hydrochloric acid (5.3) to the flask and swirl to mix. Allow to cool, dilute to the mark with water, stopper and mix thoroughly. NOTE3This is used as the solvent blan

47、k, as defined in ISO6955:1982, subclause 5.4.2, but in this International Standard the solvent blank is referred to as the acid blank. BH 4 + H + 3H 2 O H 3 BO 3+ 8H . . . (1) AsO 2 + H + 6H AsH 3+ 2H 2 O . . . (2)BS ISO 11041:1996 BSI 12-1998 3 5.5 Hydrochloric acid, diluted 1 + 4. Pour approximate

48、ly 700 ml of water (5.1) into a1000ml one-mark volumetric flask (6.2.1.5). Carefully add 200 ml of concentrated hydrochloric acid (5.3) to the flask and swirl to mix. Allow to cool, dilute to the mark with water, stopper and mix thoroughly. 5.6 Nitric acid (HNO 3 ), concentrated, r 1,42 g/ml, 69 % (

49、m/m) to 71 % (m/m). The concentration of arsenic shall be less than0,01g/ml. WARNING Concentrated nitric acid is corrosive and oxidizing, and nitric acid fumes are irritant. Avoid exposure by contact with the skin or eyes, or by inhalation of fumes. Personal protective equipment (e.g. gloves, face shield or safety spectacles, etc.) must be used when working with the concentrated or diluted nitric acid, and concentrated nitric acid must be used in a fume hood. 5.7 Sulfuric acid (H 2 SO 4 ), co