1、BRITISH STANDARD BS ISO 7981-1:2005 BS 6068-2.95:2005 Water quality Determination of polycyclic aromatic hydrocarbons (PAH) Part 1: Determination of six PAH by high-performance thin-layer chromatography with fluorescence detection after liquid-liquid extraction ICS 13.060.50 BS ISO 7981-1:2005 This
2、British Standard was published under the authority of the Standards Policy and Strategy Committee on 1 August 2005 BSI 1 August 2005 ISBN 0 580 46410 5 National foreword This British Standard reproduces verbatim ISO 7981-1:2005 and implements it as the UK national standard. The UK participation in i
3、ts preparation was entrusted by Technical Committee EH/3, Water quality, to Subcommittee EH/3/2, Physical, chemical and biochemical methods, which has the responsibility to: A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cross-references The Bri
4、tish Standards which implement international publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This p
5、ublication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible interna
6、tional/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the ISO title
7、page, pages ii to v, a blank page, pages 1 to 22, an inside back cover and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date Comments Reference number ISO 7981-1:2005(E)INTERNATIONAL STANDA
8、RD ISO 7981-1 First edition 2005-06-15 Water quality Determination of polycyclic aromatic hydrocarbons (PAH) Part 1: Determination of six PAH by high- performance thin-layer chromatography with fluorescence detection after liquid-liquid extraction Qualit de leau Dtermination des hydrocarbures aromat
9、iques polycycliques (HAP) Partie 1: Dosage de six HAP par chromatographie de haute performance sur couche mince avec dtection fluorimtrique la suite dune extraction liquide-liquide BS ISO 7981-1:2005ii BS ISO 7981-1:2005 iii Contents Page Foreword iv Introduction v 1 Scope . 1 2 Principle. 1 3 Inter
10、ferences . 2 4 Reagents 3 5 Apparatus 4 6 Sampling 5 7 Procedure 6 8 Evaluation 8 9 Calibration . 11 10 Determination of the recovery. 13 11 Blank measurements 13 12 Calculation. 13 13 Expression of results . 14 14 Test report . 15 15 Accuracy 15 Annex A (informative) R fvalues of the six PAH under
11、various chromatographic conditions . 16 Annex B (informative) Spectroscopic identification. 17 Annex C (informative) Examples for the construction of special apparatus . 18 Annex D (informative) Accuracy . 21 Bibliography . 22 BS ISO 7981-1:2005 iv Foreword ISO (the International Organization for St
12、andardization) is a worldwide federation of national standards bodies (ISO member bodies). 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 rig
13、ht to be represented on that committee. International organizations, governmental and non-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. International
14、 Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as a
15、n International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO
16、7981-1 was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 2, Physical, chemical and biochemical methods. ISO 7981 consists of the following parts, under the general title Water quality Determination of polycyclic aromatic hydrocarbons (PAH): Part 1: Determination of six P
17、AH by high-performance thin-layer chromatography with fluorescence detection after liquid-liquid extraction Part 2: Determination of six PAH by high-performance liquid chromatography with fluorescence detection after liquid-liquid extraction v Introduction Polycyclic aromatic hydrocarbons (PAH) are
18、present in nearly all types of waters. These substances are adsorbed on solids (sediments, suspended matter) as well as dissolved in the liquid phase. Some PAH are known or suspected to cause cancer. The maximum acceptable levels of PAH in waters intended for human consumption are given in European
19、Legislation 1 2 3 4 . The sum of the mass concentrations of the six PAH specified in this part of ISO 7981 normally is about 0,01 g/l to 0,05 g/l in ground water and up to 1 g/l in surface water. BS ISO 7981-1:2005blank1 Water quality Determination of polycyclic aromatic hydrocarbons (PAH) Part 1: D
20、etermination of six PAH by high-performance thin-layer chromatography with fluorescence detection after liquid-liquid extraction WARNING Some substances being measured are presumed to be carcinogenic. Acetonitrile and hexane are harmful. Persons using this part of ISO 7981 should be familiar with no
21、rmal laboratory practise. This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this part of ISO 7981 to establish appropriate safety and health practices and to ensure compliance with any national regulatory co
22、nditions. IMPORTANT It is absolutely essential that tests conducted according to this part of ISO 7981 be carried out by suitably trained staff. 1 Scope This part of ISO 7981 specifies the determination of six selected PAH in drinking water by high-performance thin-layer chromatography with fluoresc
23、ence detection after liquid-liquid extraction. The six PAH are: fluoranthene, benzobfluoranthene, benzoapyrene, benzokfluoranthene, indeno1,2,3-cdpyrene, and benzoghiperylene (see Table 1). A screening method (method A) is described to exclude those samples containing less than 20 % of the limit val
24、ues given in References 1, 2, 3 and 4. A quantitative method (method B) is also described, with a working range of 40 ng/l to 240 ng/l (sum of 6 PAH). Higher concentrations can be determined by using a smaller aliquot of the sample. With some modifications, this method is also applicable for the ana
25、lysis of ground waters and moderately polluted surface waters. 2 Principle Since PAH can to a large extent be adsorbed on particulate matter, the whole test sample is analysed. NOTE For the analysis of surface water, a differentiation between dissolved and undissolved PAH may be desirable, but this
26、is not relevant for drinking water. PAH are extracted from the water sample by liquid-liquid extraction. The extract is evaporated to dryness and the residue is taken up in a solvent and analysed. Extracts of surface waters and other contaminated water samples should be cleaned prior to analysis (7.
27、4). BS ISO 7981-1:20052 PAH are then separated by high-performance thin-layer chromatography (HPTLC) on appropriate stationary phases and detected either visually or by in situ fluorescence measurement at constant or differing wavelength combinations. Table 1 Polycyclic aromatic hydrocarbons determi
28、nable by this method Name Chemical formula Molar mass Carbon fraction CAS-number Structure g/mol Fluoranthene C 16 H 10202,26 95,0 206-44-0 Benzobfluoranthene C 20 H 12252,32 95,2 205-99-2 Benzoapyrene C 20 H 12252,32 95,2 50-32-8 Benzokfluoranthene C 20 H 12252,32 95,2 207-08-9 Indeno1,2,3-cdpyrene
29、 C 22 H 12276,34 95,6 193-39-5 Benzoghiperylene C 22 H 12276,34 95,6 191-24-2 3 Interferences 3.1 Interferences with screening method (method A) Other compounds and/or impurities can interfere in the screening method, thus the use of spectroscopic identification is recommended in order to lower the
30、occurrence of false positives in screening test samples. It may be necessary to clean coloured extracts or test samples known to contain other organic substances on silica prior to analysis (7.4). 3.2 Interferences with sampling and extraction Use sampling containers made of materials (preferably of
31、 glass or steel) that do not affect the test sample during the contact time. Avoid plastics and other organic materials during sampling, sample storage or extraction. BS ISO 7981-1:20053 If automatic samplers are used, avoid the use of silicone or rubber material for the tubes. If present, make sure
32、 that the tubes are as short as possible. Rinse the sampling line with the water to be sampled before the test sample is taken. ISO 5667-2 and ISO 5667-3 can be used for guidance. Keep the samples from direct sunlight and prolonged exposure to light. During storage of the test sample, losses of PAH
33、can occur due to adsorption on the walls of the containers. The extent of the losses depends on the storage time. 3.3 Interferences with HPTLC Substances that exhibit either fluorescence or quenching and co-elute with the PAH to be determined can interfere with the determination. These interferences
34、 can lead to incompletely resolved signals and can, depending on their magnitude, affect the accuracy and precision of the analytical results. Band overlap will make an interpretation of the result impossible. Unsymmetrical bands and bands broader than the corresponding bands of the reference substa
35、nce suggest interferences. The identity and purity of the bands can be checked by recording the excitation and emission spectra. 4 Reagents Use only reagents of recognized analytical grade (e.g. “for residue analysis” or “for HPLC analysis”) as far as available, and only distilled water or water of
36、equivalent purity showing the lowest possible fluorescence. Monitor the blank to guarantee that the reagents do not contain PAH in detectable concentrations (see Clause 11). 4.1 Solvents 4.1.1 Extraction and clean-up solvents 4.1.1.1 Cyclohexane, C 6 H 124.1.1.2 Hexane, C 6 H 144.1.1.3 Dichlorometha
37、ne, CH 2 Cl 2Other volatile solvents may be used as well, if it is proved that the recovery is equivalent or better. NOTE Dichloromethane often contains stabilizers, e.g. ethanol or amylene. Stabilizers can influence the elution strength of the eluent. Without stabilizer, free radicals might develop
38、. This can lead to degradation of PAH. The presence of hydrogen chloride indicates the presence of radicals. Hydrogen chloride can be determined by extracting dichloromethane with water and measuring the pH value. 4.1.2 HPTLC solvents 4.1.2.1 Methanol, CH 3 OH 4.1.2.2 Acetonitrile, CH 3 CN 4.1.2.3 2
39、,4-dimethyl-3-oxypentane (diisopropyl ether), C 6 H 14 O 4.1.2.4 2-propanol (isopropanol), C 3 H 7 OH 4.2 Sodium thiosulfate pentahydrate, Na 2 S 2 O 3 5H 2 O 4.3 Sodium chloride, NaCl BS ISO 7981-1:20054 4.4 Sodium sulfate, Na 2 SO 4 , anhydrous, precleaned by heating to 500 C. 4.5 Nitrogen, having
40、 a purity (volume fraction) of at least 99,999 %. 4.6 Silica, with an average particle size of approximately 40 m and stored in a desiccator to ensure maximum activity. NOTE Prepacked silica cartridges are commercially available. 4.7 Molecular sieve beads, pore size 0,4 nm. 4.8 Caffeine, C 8 H 10 N
41、4 O 24.9 Liquid paraffin 4.10 Reference substances (see Table 1) Because of the dangerous nature of the substances to be used, it is highly recommended to use commercially available, preferably certified, standard solutions. Avoid skin contact. 4.11 Single-substance stock solutions, of those listed
42、in Table 1, diluted in cyclohexane (4.1.1.1) or methanol (4.1.2.1) to a mass concentration of, for example, 10 g/ml. 4.12 Multiple-substance stock solution, preferably certified, diluted in cyclohexane (4.1.1.1) or methanol (4.1.2.1) to a mass concentration of, for example, 10 g/ml for fluoranthene
43、and 2 g/ml for the other reference substances (4.10). 4.13 Calibration solutions Transfer 20 l, 40 l, 60 l, 80 l, 100 l and 120 l of the stock solution (4.12) into a graduated 10 ml flask (5.14) and make up to volume with cyclohexane (4.1.1.1) or methanol (4.1.2.1). 1 ml of this reference solution c
44、ontains 20 ng, 40 ng, 60 ng, 80 ng, 100 ng and 120 ng of fluoranthene and 4 ng, 8 ng, 12 ng, 16 ng, 20 ng and 24 ng of the other reference substances (4.10). NOTE The solutions 4.11 to 4.13 are stable for at least one year when stored in the dark at room temperature and protected from evaporation. 5
45、 Apparatus Use standard laboratory apparatus, cleaned to eliminate all interferences. Clean all glassware, for example by rinsing with detergent and hot water, and dry for about 15 min to 30 min at about 120 C. After cooling, rinse with acetone, seal the glassware and store in a clean environment. G
46、lassware that has been in contact with waste water samples or samples with high PAH concentrations shall not be re-used for drinking water analysis. 5.1 Brown glass bottles, narrow-necked, flat-bottomed, nominal capacity 1 000 ml, with solid glass stopper. 5.2 Magnetic stirrer with stirring rods, PT
47、FE-coated, kept under cyclohexane, with a maximum rotational frequency of 1 000 min 1 . 5.3 Measuring cylinders, nominal capacities 10 ml, 25 ml and 1 000 ml. 5.4 Separating funnel, nominal capacity 1 000 ml, with PTFE stopcock, kept under cyclohexane, and glass stopper, e.g. a Squibb funnel. BS ISO
48、 7981-1:20055 5.5 Conical flask, nominal capacity 100 ml, with glass stopper. 5.6 Reduction flask, nominal capacity 50 ml (see Figure C.1). 5.7 Centrifuge with rotor and centrifuge tubes, with tapered bottom, nominal capacity 50 ml (see Figure C.2) and with a rotational frequency of about 3 000 min
49、1 . 5.8 Pasteur pipettes 5.9 Evaporation assembly, such as a rotary evaporator with vacuum stabilizer and water bath. 5.10 Shaking apparatus, with adjustable rotational speed, suitable for test tubes. 5.11 Blow-down assembly, nitrogen pressure cylinder with pressure-reducing valve and needle valve for fine adjustment. 5.12 Polypropene or glass cartridges, filled with at least 0,5 g silica (4.6). 5.13 Glass v
