1、Designation: D4458 15Standard Test Method forChloride Ions in Brackish Water, Seawater, and Brines1This standard is issued under the fixed designation D4458; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision
2、. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method2is applicable to the measurement ofchloride in highly mineralized waters such as oil field brines,seawater, and b
3、rackish water. The test method is based uponthe titration of chloride with silver nitrate, using a visualindicator.1.2 Samples containing from 10 to 150 mg of chloride canbe analyzed by this test method. These levels are achieved bydilution as described in the test method.1.3 The values stated in SI
4、 units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 It is the users responsibility to assure the validity of themethod for untested types of water.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use
5、. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3D1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD277
6、7 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD3370 Practices for Sampling Water from Closed ConduitsD5810 Guide for Spiking into Aqueous SamplesD5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water Analys
7、is3. Terminology3.1 DefinitionsFor definitions of terms used in this testmethod, refer to Terminology D1129.4. Summary of Test Method4.1 This test method is based upon the Mohr procedure fordetermining chloride ion with silver nitrate. The chloride reactswith the silver ion before any silver chromat
8、e forms, due to thelower solubility of silver chloride. The potassium chromateindicator reacts with excess silver ion to form a red silverchromate precipitate. The end point is the appearance of thefirst permanent orange color.4.2 This test method is suitable for analyzing solutions witha pH between
9、 6.0 and 8.5.5. Significance and Use5.1 Chloride is present in virtually all oil field brines,seawaters, and many waste waters. Identification of the originof the water and selection of its disposal method may be basedupon the chloride content. The chloride content is also used toestimate the resist
10、ivity of formation waters and to differentiatebetween subsurface formations.6. Interferences6.1 Sulfide, bromide, iodide, thiocyanate, cyanide,phosphate, sulfite, carbonate, hydroxide, and iron interfere inthis test method. Sulfide, sulfite, and thiosulfate can be re-moved with a peroxide treatment,
11、 but usually no attempt ismade to remove bromide and iodide because they are usuallypresent in insignificant quantities compared to chloride. Ifnecessary, the pH can be raised and the hydroxides of severalmetals, including iron, can be filtered off. Iron, barium, lead,and bismuth precipitate with th
12、e chromate indicator.7. Apparatus7.1 Laboratory Glassware.7.2 Buret, 25-mL capacity.7.3 Hotplate.7.4 Magnetic Stirrer and TFE-fluorocarbon-Coated StirringBars.1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of D19.05 on Inorganic Constituent
13、s in Water.Current edition approved Feb. 1, 2015. Published March 2015. Originallyapproved in 1985. Last previous edition approved in 2009 as D4458 09. DOI:10.1520/D4458-15.2Hillebrand, W. F., Lundell, G. E. F., Bright, H. A., and Hoffman, J. I., AppliedInorganic Analysis, 2nd Ed., 732, John Wiley b
14、rines; chloride ion; seawater; silvernitrateSUMMARY OF CHANGESCommittee D19 has identified the location of selected changes to this standard since the last issue(D4458 09) that may impact the use of this standard. (Approved Feb. 1, 2015.)(1) Added 8.8.(2) Revised the equation in 11.1.(3) Revised Sec
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