Potentiometric Microdetermination of Tungsten in Organic Compounds after Combustion in a Modified Oxygen Flask

✍ Scribed by Antonio Campiglio

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 85 KB
• Volume: 55
• Category: Article
• ISSN: 0026-265X
• DOI: 10.1006/mchj.1996.1319

✦ Synopsis

A new method for the microdetermination of tungsten in organic compounds such as phosphotungstate and silicotungstate of basic organic compounds is described. The sample is burnt in a modified oxygen flask, the products are absorbed in a sodium hydroxide solution, and complete dissolution of WO 3 formed is achieved by boiling the solution for 6-7 min. After removal of carbon dioxide and appropriate pH adjustment, W(VI) is titrated potentiometrically with 10 mM Pb(NO 3 ) 2 by using a lead(II) ion-selective electrode as indicator electrode and a double-junction reference electrode. Accurate and precise results are obtained. The absolute error does not exceed 0.14%; the recoveries of tungsten are in the range from 99.74 to 100.00%. The mean relative standard deviation is 0.10%.