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Journal of Chemistry
Volume 2013, Article ID 719179, 4 pages
http://dx.doi.org/10.1155/2013/719179
Research Article

Interference of Lithium in Measuring Magnesium by Complexometry: Discussions of the Mechanism

1Tianjin Key Laboratory of Marine Resources and Chemistry, College of Marine Science & Engineering, Tianjin University of Science & Technology, Tianjin 300457, China
2Department of Chemistry & Biochemistry, Laurentian University, Sudbury, ON, Canada P3E 2C6

Received 25 May 2013; Revised 25 July 2013; Accepted 29 July 2013

Academic Editor: Danielle Ballivet-Tkatchenko

Copyright © 2013 Jie Gao et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

There is usually a large concentration of magnesium in the brine of salt lakes and as a consequence it is difficult to measure Mg2+ accurately with the complexometric titration by ethylenediaminetetraacetic acid disodium salt (EDTA) because of the large levels of Li+ also coexisting in brine samples. In this study, a relationship between the relative error related to the number of drops of the indicator and the NMR spectra of anhydrous ethanol and n-butanol, with or without LiCl, was analyzed and compared. It was then possible to suggest a mechanism to explain the interference of Li+ when measuring Mg2+ and to control the interference in the alcohol mixture because Li+ can then complex with the alcohols and mainly form a complex with n-butanol.