Villagrán Constanza, Banks Craig E, Hardacre Christopher, Compton Richard G
The QUILL Centre and The School of Chemistry, Queen's University Belfast, Belfast BT9 5AG, Northern Ireland, U.K.
Anal Chem. 2004 Apr 1;76(7):1998-2003. doi: 10.1021/ac030375d.
The electroanalytical quantification of chloride in [C4mim][BF4], [C4mim][NTf2], and [C4mim][PF6] ionic liquids has been explored using linear sweep and square wave voltammetry. Cathodic stripping voltammetry at a silver disk electrode is found to be the most sensitive. The methodology is based on first holding the potential of the electrode at +2.0 V (vs Ag wire), to accumulate silver chloride at the electrode. On applying a cathodic scan, a stripping wave is observed corresponding to the reduction of the silver chloride. This stripping protocol was found to detect ppb levels of chloride in [C4mim][BF4], [C4mim][NTf2], and [C4mim][PF6]. Although other methods for chloride have been reported for BF4- and PF6-based ionic liquids, no methods have been reported for NTf2 ionic liquids.
