APHA-AWWA-WEF

Ammonium chloride is analyzed by treatment with formaldehyde (neutralized with NaOH) and the product HCl formed is analyzed by titration using an acid-base color indicator such as phenolphthalein. Alternatively, it may be mixed with caustic soda solution and distdled. The distillate may be analyzed for NH3 by titration with H2SO4 or by colorimetric Nesslerization or with an ammonia-selective electrode (APHA, AWWA, WEF. 1995. Standard Methods for the Examination of Water and Wastewater. 19th ed. Washington, DC, American Pubhc Health Association). The presence of ammonia or any other ammonium compound would interfere in the test. The moisture content in NH4CI may be determined by Karl—Fischer method. 

Elemental composition H 3.73%, C 44.44%, N 51.83%. HCN may be analyzed by GC or GC/MS. The aqueous solution may be directly injected onto the GC column and determined by an FID. For GC/MS determination, an alcoholic solution may be injected into the column. The characteristic mass ions are 27 and 26. The cyanide ion in aqueous solution also may be measured by cyanide ion-selective electrode, titrimetry, and by colorimetric methods (APHA, AWWA, WEF. 1999. Standard Methods for the Examination of Water and Wastewater, 20th ed. Washington, DC American Public Health Association). For colorimetric analysis, the aqueous solution may be treated with a dilute caustic soda solution, followed by treatment with chloramine-T, and then with pyridine-barbituric acid reagent. A red-blue color develops, the absorbance of which is measured by spectrophotometer at 578 nm. The concentration of CN is determined from a standard cahbration curve using KCN standards. 

Franson, MA, ed. 1998. Standard methods 4500-C102, amperometric method II. In Standard. Methods for the Examination of Water and Wastewater, 20th Ed. Baltimore, MD APHA/AWWA/WEF. Pp. 4-73-4-79. 

APHA, AWWA, WEF (1992). Standard Methods for the Examination of Water and Waste-water. American Pnblic Health Association, Washington. 

Standard Methods for Examination of Water and Wastewater (1998) 20th Edn, APHA AWWA WEF, 3-1 3-105. ISBN 0-87553-235-7. 

APHA-AWWA-WEF (1995) Standard methods for the examination of water and wastewater. In Eaton AD, Clesceri LS, Greenberg AE (eds), 19th edn. American Public Health Association, Washington, DC... 

Water, wastewater, and brine FIA 0.7 pg P (from 21 replicates of a 5.0 pg P L-i standard) Silica, arsenate, and iron at high concentration (>30 mg L ) Formation of antimony-phosphomolybdate complex reduced by ascorbic acid APHA-AWWA-WEF 2005 Method 4500-P G [128]... 

Surface water. Ion Function of sample size Any substance that has a retention Separation by ion exchanger with APHA-AWWA-WEF... 

Acid sulfuric and persulfate Manual digestion + 2.0 pg (with a APHA-AWWA-WEF 2005... 

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