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 978-0-626-24444-6 SANS 6169:2010Edition 1.2SOUTH AFRICAN NATIONAL STANDARD Water Aluminium 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 6169:2010 Edition 1.2 Table of changes Change No. Date Scope Amdt 1 2005 Amended to change the designation of SABS standards to SANS standards and to update referenced standards. Amdt 2
5、2010 Amended to update referenced standards. Foreword This South African standard was approved by National Committee SABS 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 p
6、ublished in April 2010. This document supersedes SANS 6169:2005 (edition 1.1). A vertical line in the margin shows where the text has been technically modified by amendment No. 2. SANS 6169:2010 Edition 1.2 1 Water Aluminium content 1 Scope and field of application This standard specifies a method o
7、f determining the aluminium content of water and wastewater, using a nitrous oxide-acetylene flame and direct flame atomic absorption. The method is applicable to the determination of aluminium in the concentration range 0,1 mg/L to 100 mg/L. 2 Normative references The following referenced documents
8、 are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. Information on currently valid national and international standards can be obtained
9、 from the SABS Standards Division. Amdt 1 SANS 111/ISO 835, Laboratory glassware Graduated pipettes. Amdt 1; amdt 2 SANS 112/ISO 648, Laboratory glassware Single volume pipettes. Amdt 1 SANS 115/ISO 385, Laboratory glassware Burettes. Amdt 1; amdt 2 SANS 128/ISO 1042, Laboratory glassware One-mark v
10、olumetric flasks. Amdt 1 SANS 3696/ISO 3696, Water for analytical laboratory use Specification and test methods. SANS 6168, Water Pretreatment for metal analysis. 3 Principle The pretreated sample is aspirated into a nitrous oxide-acetylene flame, using potassium as an ionization suppressor. The abs
11、orbance measured at 309,3 nm is compared with the absorbance of aluminium standards measured under the same conditions. 4 Reagents NOTE Unless otherwise specified, only use water that complies with the requirements of SANS 3696 and reagents of analytical reagent grade. 4.1 Nitric acid (HNO3) Concent
12、rated (d at 25 /25 C = 1,42). SANS 6169:2010 Edition 1.2 2 4.2 Acidified water Containing 1,5 mL of HNO3(see 4.1) per litre. 4.3 Aluminium stock solution (1 000 mg/L) 4.3.1 Obtain a commercially available stock solution of aluminium (1 000 mg/L) of guaranteed quality, or prepare the stock solution a
13、s described in 4.3.2. 4.3.2 Dissolve 17,584 g of aluminium potassium sulfate (AlK(SO4)212H2O), previously dried in a desiccator for 24 h, in 200 mL of water. Add 1,5 mL of HNO3(see 4.1) and dilute with water to 1 000 mL in a volumetric flask. 4.4 Aluminium working stock solution (100 mg/L) Pipette 1
14、0,0 mL of the stock solution (see 4.3) into a 100 mL volumetric flask and dilute to the mark with acidified water (see 4.2). 4.5 Aluminium standard solutions (0,1 mg/L to 100 mg/L) 4.5.1 Prepare at least three aluminium standard solutions that will bracket the expected concentration of the sample by
15、 dilution of the working stock solution (see 4.4), using the acidified water (see 4.2) as the diluent. 4.5.2 Add 2,0 mL of the KCl solution (see 4.6) to 100 mL of each of the standards. 4.6 Potassium chloride (KCl) solution (250 g/L) Dissolve 250 g of KCl in water and dilute to 1 000 mL in a volumet
16、ric flask. 5 Apparatus 5.1 Atomic absorption spectrophotometer For use at 309,3 nm. 5.2 Nitrous oxide burner Suitable for attachment to the spectrophotometer (see 5.1). 5.3 Aluminium hollow-cathode lamp 5.4 Oxidant 5.4.1 Air, dried and filtered to support combustion before switching to nitrous oxide
17、. 5.4.2 Nitrous oxide, commercially bottled gas. 5.5 Fuel Acetylene, standard commercial grade. (Replace the cylinder when the cylinder pressure drops to 700 kPa.) SANS 6169:2010 Edition 1.2 3 CAUTION: Never allow the operating pressure of acetylene to exceed 105 kPa. 5.6 Pressure-reducing regulator
18、s For the supply of fuel and oxidant to the instrument at the appropriate levels recommended by the manufacturer. 5.7 Glassware Where applicable, only use burettes, pipettes and volumetric flasks that comply with the requirements for class A items as specified in SANS 111, SANS 112, SANS 115 and SAN
19、S 128, as relevant. Amdt 1; amdt 2 6 Sample pretreatment 6.1 Pretreat the sample, a blank (see 4.2) and at least one standard (see 4.5.1) in accordance with SANS 6168 in order to analyse for the appropriate form of metal, i.e. soluble, insoluble or total metal. NOTE For the purposes of legislation o
20、r specifications relating to this method, pretreat the sample for recovery of total aluminium, unless specifically indicated otherwise. 6.2 Add 2,0 mL of the KCl solution (see 4.6) per 100 mL of each sample, standard(s) and blank after pretreatment as in 6.1, and mix well. 7 Procedure 7.1 Instrument
21、 operation NOTE The differences between makes and models of atomic absorption spectrophotometers make it impracticable to formulate detailed operating instructions. Follow the manufacturers operating instructions for the specific instrument but, in general, proceed in accordance with the instruction
22、s given in 7.1.1 to 7.1.12. 7.1.1 Turn on the instrument, install the aluminium hollow-cathode lamp (see 5.3) and apply the current recommended by the manufacturer. 7.1.2 Set the wavelength at 309,3 nm and set the slit width in accordance with the manufacturers instructions. 7.1.3 Allow the lamp to
23、stabilize for approximately 10 min and then align it to obtain optimum transmission. 7.1.4 Adjust the fine control of the wavelength setting of the monochromator in order to ensure maximum response. 7.1.5 Install the nitrous oxide burner (see 5.2). 7.1.6 Check and, if necessary, adjust the gas flow
24、rates to ensure that they are at the levels specified for the instrument. 7.1.7 Turn on the air supply and then the acetylene flow, and ignite the mixture. 7.1.8 Increase the acetylene flow rate to give an acetylene-rich (white) flame. SANS 6169:2010 Edition 1.2 4 7.1.9 With a rapid motion, switch f
25、rom air to nitrous oxide and so increase the flow rate of the acetylene that the flame has a red core, of height approximately 20 mm. 7.1.10 Aspirate the acidified water (see 4.2) and, if necessary, check that the aspiration rate is in the range 3 mL/min to 5 mL/min and then zero the instrument in t
26、he absorbance mode. 7.1.11 Aspirate a standard that will give an absorbance exceeding 0,2, and optimize the burner position until the maximum absorbance value is recorded. The instrument is now ready for calibration and analysis. 7.1.12 After analysis, extinguish the flame by rapidly switching from
27、nitrous oxide to air. Allow the flame to stabilize and then turn off the acetylene. When the flame is extinguished, turn off the air supply. 7.2 Instrument calibration 7.2.1 Aspirate the analyte blank (see 4.2) and zero the instrument. 7.2.2 Aspirate each of the standard solutions (see 4.5.2), using
28、 the acidified water (see 4.2) to flush the nebulizer between aspirations, and record their respective absorbances. 7.2.3 Construct a calibration curve, using the standard concentrations and their respective absorbances. 7.3 Sample analysis 7.3.1 Aspirate the pretreated blank, standard(s) and sample
29、 (see 6.2), using the acidified water (see 4.2) to flush the nebulizer between aspirations. 7.3.2 Record the absorbances and determine the concentrations by referring to the calibration curve as constructed in 7.2.3, or record the concentrations directly if an instrument with concentration mode is u
30、sed. 7.3.3 Correct the results for the sample and the control standard(s) by subtracting the result for the pretreated blank, if applicable, and verify the absence of interference due to the pretreatment method by confirmation of the true concentration(s) of the control standard(s). 8 Expression of
31、results So express the result as to indicate the form of metal analysed and the concentration units used, e.g. Total aluminium as Al in mg/L. SABS SABS Standards Division The objective of the SABS Standards Division is to develop, promote and maintain South African National Standards. This objective
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