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 978-0-626-24319-7 SANS 5214:2010Edition 3.2SOUTH AFRICAN NATIONAL STANDARD Water Zinc content Published by SABS Standards Division 1 Dr Lategan Road
4、 Groenkloof Private Bag X191 Pretoria 0001Tel: +27 12 428 7911 Fax: +27 12 344 1568 www.sabs.co.za SABS SANS 5214:2010 Edition 3.2 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 2010
5、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 publis
6、hed in April 2010. This document supersedes SANS 5214:2005 (edition 3.1). A vertical line in the margin shows where the text has been technically modified by amendment No. 2. SANS 5214:2010 Edition 3.2 1 Water Zinc content 1 Scope and field of application This standard specifies a method of determin
7、ing the zinc content of water and wastewater, using an air-acetylene flame and direct flame atomic absorption. The method is applicable to the determination of zinc in the concentration range 0,01 mg/L to 2,0 mg/L. 2 Normative references The following referenced documents are indispensable for the a
8、pplication 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 from the SABS Standards Div
9、ision. 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 volumetric flasks. Amdt 1 SAN
10、S 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 an air-acetylene flame under oxidizing conditions and the absorbance measured at 213,9 nm is compared with the ab
11、sorbances of zinc 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) Concentrated (d at 25 /25 C = 1,42). SANS 5214:2010 Edition 3.2
12、 2 4.2 Dilute nitric acid 1 + 1 HNO3. 4.3 Acidified water Containing 1,5 mL of HNO3(see 4.1) per litre. 4.4 Zinc stock solution (1 000 mg/L) 4.4.1 Obtain a commercially available stock solution of zinc (1 000 mg/L) of guaranteed quality, or prepare the stock solution as described in 4.4.2. 4.4.2 Dis
13、solve 1,245 g of zinc oxide (ZnO), previously dried at 105 C for 1 h and cooled in a desiccator, in 20 mL of the dilute HNO3(see 4.2) and dilute with water to 1 000 mL in a volumetric flask. 4.5 Zinc working stock solution (100 mg/L) Pipette 10,0 mL of the stock solution (see 4.4) into a 100 mL volu
14、metric flask and dilute to the mark with the acidified water (see 4.3). 4.6 Zinc standard solutions (0,01 mg/L to 2,0 mg/L) Prepare at least three zinc standard solutions that will bracket the expected concentration of the sample by dilution of the working stock solution (see 4.5), using the acidifi
15、ed water (see 4.3) as the diluent. 5 Apparatus 5.1 Atomic absorption spectrophotometer, for use at 213,9 nm. 5.2 Air-acetylene burner, suitable for attachment to the spectrophotometer (see 5.1). 5.3 Zinc hollow-cathode lamp. 5.4 Oxidant, air, dried and filtered. 5.5 Fuel, acetylene, standard commerc
16、ial grade. (Replace the cylinder when the cylinder pressure drops to 700 kPa.) CAUTION: Never allow the operating pressure of acetylene to exceed 105 kPa. 5.6 Pressure-reducing regulators, for the supply of fuel and oxidant to the instrument at the appropriate levels recommended by the manufacturer.
17、 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 SANS 128, as relevant. Amdt 1; amdt 2 SANS 5214:2010 Edition 3.2 3 6 Sample pretreatment Pretreat the sample, a bla
18、nk (see 4.3) and at least one standard 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 or specifications relating to this method, pretreat the sample for recovery of total zinc, unless spe
19、cifically indicated otherwise. 7 Procedure 7.1 Instrument 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 bu
20、t, in general, proceed in accordance with the instructions given in 7.1.1 to 7.1.10. 7.1.1 Turn on the instrument, install the zinc hollow-cathode lamp (see 5.3) and apply the current recommended by the manufacturer. 7.1.2 Set the wavelength at 213,9 nm and set the slit width in accordance with the
21、manufacturers instructions. 7.1.3 Allow the lamp to 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 air-acetylene burner (see 5.2).
22、 7.1.6 Check and, if necessary, adjust the gas flow 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 Ensure that the flame is oxidizing (non-luminous with a hazy blue inner core), and the
23、n zero the instrument in the absorbance mode. 7.1.9 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. 7.1.10 After analysis, extinguish the flame b
24、y turning off the acetylene flow first. When the flame is extinguished, turn off the air supply. 7.2 Instrument calibration 7.2.1 Aspirate the analyte blank (see 4.3) and zero the instrument. 7.2.2 Aspirate each of the standard solutions (see 4.6), using the acidified water (see 4.3) to flush the ne
25、bulizer between aspirations, and record their respective absorbances. 7.2.3 Construct a calibration curve, using the standard concentrations and their respective absorbances. SANS 5214:2010 Edition 3.2 4 7.3 Sample analysis 7.3.1 Aspirate the pretreated blank, standard(s) and sample (see clause 6) u
26、sing the acidified water (see 4.3) 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 used. 7.3.3 Co
27、rrect 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 results So ex
28、press the result as to indicate the form of metal analysed and the concentration units used, e.g. Total zinc as Zn 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 is incorporated i
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