1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA
2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any
3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. ISBN 978-0-626-24442-2 SANS 6059:2010Edition 2.1 SOUTH AFRICAN NATIONAL STANDARD Water Mercury content Published by SABS Standards Division 1 Dr Lategan
4、Road Groenkloof Private Bag X191 Pretoria 0001Tel: +27 12 428 7911 Fax: +27 12 344 1568 www.sabs.co.za SABS SANS 6059:2010 Edition 2.1 Table of changes Change No. Date Scope Amdt 1 2010 Amended to update referenced standards. Foreword This South African standard was approved by National Committee SA
5、BS SC 147A, Water Water sampling and analysis, in accordance with procedures of the SABS Standards Division, in compliance with annex 3 of the WTO/TBT agreement. This document was published in April 2010. This document supersedes SANS 6059:2005 (edition 2). A vertical line in the margin shows where
6、the text has been technically modified by amendment No. 1. SANS 6059:2010 Edition 2.1 1 Water Mercury content 1 Scope and field of application This standard specifies a method for the determination of the mercury content of water and wastewater by using atomic absorption spectrophotometry. The metho
7、d is applicable to the determination of mercury in the concentration range 0,001 mg/L to 0,010 mg/L. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the lat
8、est edition of the referenced document (including any amendments) applies. Information on currently valid national and international standards can be obtained from the SABS Standards Division. SANS 111/ISO 835, Laboratory glassware Graduated pipettes. Amdt 1 SANS 112/ISO 648, Laboratory glassware Si
9、ngle volume pipettes. SANS 115/ISO 385, Laboratory glassware Burettes. Amdt 1 SANS 128/ISO 1042, Laboratory glassware One-mark volumetric flasks. SANS 3696/ISO 3696, Water for analytical laboratory use Specification and test methods. 3 Principle The pretreated water sample is injected into a stannou
10、s chloride solution at a wavelength of 253,6 nm in a cold vapour generator cell atomic absorption system and compared with the peak heights of mercury standards measured under the same conditions. 4 Reagents 4.1 General Unless otherwise specified, only use water that complies with the requirements o
11、f SANS 3696 and reagents of analytical reagent grade. SANS 6059:2010 Edition 2.1 2 4.2 Magnesium perchlorate (MgClO4) Granular, of particle size within the range 0,7 mm to 1,2 mm. 4.3 Nitric acid Concentrated (d at 25 /25 C = 1,42). 4.4 Dilute nitric acid solution 1,5 mL of the concentrated nitric a
12、cid diluted to 1 L with water. 4.5 Nitrogen gas (N2) High purity grade. 4.6 Potassium permanganate solution Dissolve 50 g of potassium permanganate (KMnO4) in water and dilute to 1 000 mL. 4.7 Potassium persulfate solution Dissolve 50 g of potassium persulfate (K2S2O8) in water and dilute to 1 000 m
13、L. 4.8 Sodium chloride-hydroxylamine sulfate solution Dissolve 120 g of sodium chloride and 120 g of hydroxylamine sulfate (NH2OH)2H2SO4) in water and dilute to 1 000 mL. 4.9 Standard mercury solutions 4.9.1 Stock solution (1 000 mg/L) 4.9.1.1 Obtain a commercially available stock solution of mercur
14、y (1 000 mg/L) of guaranteed quality, or prepare a stock solution as described in 4.9.1.2. 4.9.1.2 Dissolve 1,354 0 g of mercuric chloride (HgCl2) in about 700 mL of water, add 1,5 mL of the concentrated nitric acid (see 4.3), and dilute to 1 000 mL with water. 1 mL of this solution contains 1,00 mg
15、 of mercury. 4.9.2 Standard working solution (0,1 mg/L) Dilute 10,00 mL of the stock solution (see 4.9.1) to 1 000 mL with water (see 4.1) in a volumetric flask. Dilute 10,00 mL of the resulting solution with the dilute nitric acid solution (see 4.4) to 1 000 mL in a volumetric flask. 1,00 mL of thi
16、s solution contains 0,1 g of mercury. 4.10 Stannous chloride solution Dissolve 20 g of stannous chloride (SnCl2) in 100 mL of the dilute sulfuric acid solution (see 4.12). 4.11 Sulfuric acid Concentrated (d at 25 /25 C = 1,84). SANS 6059:2010 Edition 2.1 3 4.12 Dilute sulfuric acid solution 53 mL of
17、 the concentrated sulfuric acid diluted to 1 L with water. 5 Apparatus 5.1 Atomic absorption spectrophotometer, together with the associated equipment, and a recorder. 5.2 Mercury hollow-cathode lamp. 5.3 Glass atomizing tube, as shown in figure 1. 5.4 Drying tube, 150 mm 18 mm, as shown in figure 2
18、. 5.5 Cold vapour generator cell, as shown in figure 2. 5.6 Syringe, capable of delivering 10,0 mL. 5.7 Rotameter, to set the nitrogen flow rate at 400 mL/min to 500 mL/min. 5.8 Glassware. Where applicable, only use burettes, pipettes and volumetric flasks that comply with the requirements for class
19、 A items as specified in SANS 111, SANS 112, SANS 115 and SANS 128, as relevant. Amdt 1 6 Procedure 6.1 Instrument operation NOTE The differences between makes and models of atomic absorption spectrophotometers make it impracticable to formulate detailed operating instructions. Follow the manufactur
20、ers operating instructions for the specific instrument but, in general, proceed in accordance with the instructions given in 6.1.1 to 6.1.7 6.1.1 Turn on the instrument, install the mercury hollow-cathode lamp (see 5.2) and apply the current recommended by the manufacturer. 6.1.2 Set the wavelength
21、at 253,6 nm and set the slit width in accordance with the manufacturers instructions. 6.1.3 Allow the lamp to stabilize for approximately 10 min and then align it to obtain optimum transmission. 6.1.4 Adjust the fine control of the wavelength setting of the monochromator in order to ensure maximum r
22、esponse. 6.1.5 Place the atomizing tube in position in the light path, i.e. on top of a support, holding it in position with Terry clips. 6.1.6 Connect the outlet of the vapour generator cell (see 5.5) to one end of the drying tube (see 5.4), which contains about 20 g of magnesium perchlorate, and u
23、se flexible tubing to connect the other end of the drying tube to the inlet of the atomizing tube. SANS 6059:2010 Edition 2.1 4 6.1.7 Connect the inlet at the bottom of the generator cell to a nitrogen source via a flowmeter (rotameter (see 5.7) and set the nitrogen flow at 450 mL/min. 6.1.8 Connect
24、 the recorder to the spectrophotometer. 6.2 Preparation of standards 6.2.1 Prepare a series of mercury standards by transferring 1 mL; 2 mL; 5 mL; 10 mL, etc. of the standard working solution (i.e. 0,1 g; 0,2 g; 0,5 g; 1,0 g, etc. of mercury) to separate 250 mL Erlenmeyer flasks and adding 100 mL of
25、 water to each. 6.2.2 To each flask add 5 mL of concentrated sulfuric acid (see 4.11) and 2,5 mL of concentrated nitric acid (see 4.3). 6.2.3 To each flask add 15 mL of the potassium permanganate solution (see 4.6) and allow to stand for at least 15 min. 6.2.4 To each flask add 8 mL of the potassium
26、 persulfate solution (see 4.7) and heat over a boiling waterbath for 2 h. 6.2.5 Cool to room temperature and add 6 mL of the sodium chloride-hydroxylamine sulfate solution (see 4.8) to reduce the excess permanganate. 6.2.6 Transfer to 200 mL volumetric flasks and make up to the mark with water. 6.3
27、Preparation of test sample Take 100 mL of the sample, or a smaller aliquot that has been diluted to 100 mL, transfer to a 250 mL Erlenmeyer flask, and proceed with the operations described in 6.2.2 to 6.2.6. 6.4 Analysis of test sample 6.4.1 Place 1 mL of the stannous chloride solution (see 4.10) in
28、 the vapour generator cell. Turn the 3-way stopcock at the bottom of the cell to allow the nitrogen gas (see 4.5) to flow through the cell. Suck up 10 mL of the test sample in the syringe (see 5.6) which is fitted with a large-bore needle. Provide the syringe with a rubber collar so as to make a gas
29、-tight joint and place it in the top opening of the generator cell. After the instrument has stabilized at zero, inject the test specimen as rapidly as possible into the generator cell. If mercury is present in the liquid, a reading will be obtained on the recorder. Allow at least 30 s for the maxim
30、um reading to be obtained. 6.4.2 When the recorder has again returned to zero, turn the 3-way tap to allow the solution to discharge to waste from the generator cell. Rinse the generator cell with water before proceeding with the standard solutions as in 6.4.3. 6.4.3 Treat the prepared standards (se
31、e 6.2) in the same way and plot a calibration curve of peak height against mass, in micrograms, of mercury. 6.4.4 From the calibration curve read off the quantity of mercury in the test sample. SANS 6059:2010 Edition 2.1 5 7 Calculation Calculate the mercury content c Hg in milligrams per litre, as
32、follows: c Hg = Vmwhere m is the mass of mercury in the sample aliquot, in micrograms; V is the volume of the sample aliquot, in millilitres. 8 Expression of results So express the results as to indicate the form of metal analysed and the concentration units used, for example “Total mercury as Hg in
33、 mg/L”. SANS 6059:2010 Edition 2.1 6 Figure 1 Atomizing tube Figure 2 Cold vapour generator cell and drying tube SABS SABS Standards Division The objective of the SABS Standards Division is to develop, promote and maintain South African National Standards. This objective is incorporated in the Stand
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