International Standard (ISo 6059 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEXAYHAPOAHAA OPrAHM3AUWH HO CTAHAAPTW3AUMWORGANISATION INTERNATIONALE DE NORMALISATION Water quality - Determination of the sum of calcium and magnesium -- EDTA titrimetric method Qualité de I'eau -- Dosage de la somme du calcium et du magnésium -- Methode titrimétrique a I'EDTA First edition - 1984-06-01 ISO 6059-1984 (E) UDC 543.3: 543.24 : 546.41 : 546.46 Ref. No. ISO 6059-1984 (E) Descriptors : water, quality. chemical analysis, determination of content, calcium, magnesium, voiumetric analysis. Price based on 4 pages No reproduction or networking per Foreword Iso (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of developing International Standards is carried out through Iso technical committees. Every member body interested in a subject for which a technical committee has been authorized has the and non-governmental, in liaison with Iso, also take part in the work. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the ISo Council. International Standard ISO 6059 was developed by Technical Committee ISO/TC 147 Water quality, and was circulated to the member bodies in January 1983. It has been approved by the member bodies of the following countries: Australia Hungary Poland Austria India Romania Belgium Iran South Africa, Rep. of Iraq Spain Canada Italy Sweden China ueder Switzeriand Czechoslovakia Korea, Dem. P. Rep. of Thailand Denmark Korea, Rep.of United Kingdom Finland Netherlands USSR France New Zealand Germany, F. R. Norway No member body expressed disapproval of the document. ? International Organization for Standardization, 1984 Printed in Switzerland No reproductic networking permitted without license from IHS Not for Resale ISO6059-1984 (E) INTERNATIONAL STANDARD Water quality - Determination of the sum of calcium and magnesium - EDTA titrimetric method Scope and field of application Reagents This International Standard specifies a titrimetric method using During the analysis, use only reagents of recognized analytical ethylenediaminetetraacetic acid (EDTA) for the determination grade and only distilled water or water of equivalent purity. of the sum of the calcium and magnesium concentrations in ground waters, surface waters and drinking waters. 4.1 Buffersolution. The method is not intended for effluents and waters having a Dissolve 67,5 g of ammonium chloride (NH4Cl) in 570 ml of high concentration of salts, such as sea waters. The lowest ammonia solution [25 % (m/m); Q20 = 0,910 g/mll. Then concentration that can be determined is 0,05 mmol/1. add 5,0 g of the disodium magnesium salt of EDTA (ChoH12N20gNa2Mg) and dilute to 1 000 ml with water. Store the solution (shelf-life limited) in a polyethylene bottle. 2 References Dilute 10 ml of the solution to 100 ml with water. If this solution fails to givea pH value of 10± 0,1,discard the original solu- Iso 385/1,Laboratory glassware - Burettes - Part 1: tion. General requirements. 1) 4.2 EDTA, standard volumetric solution, Iso 5667,Water quality -Sampling- c(Na2EDTA) ~ 10 mmol/l. Part 1: Guidance on the design of sampling programmes. Part2:Guidanceonsamplingtechniques. 4.2.1 Preparation Part 3: Guidance on the preservation and handling of Dry a portion of the disodium salt of EDTA dihydrate samples. 2) (C1oH14N20gNa2:2H20) at 80 °C for 2 h, dissolve 3,725 g of the dry salt in water and dilute to 1 000 ml in a volumetric flask. Store the EDTA solution in a polyethylene bottle and check the 3 Principle concentration at regular intervals. Complexometric titration of calcium and magnesium with an 4.2.2 Standardization aqueous solution of thedisodiumsaltof EDTAatapHvalue of 10. Mordant black 11, which forms a claret or violet colour in Standardize the solution (4.2.1) against the ca