TITLE:
Sensitive Determination of Metal Ions in Drinking Water by Capillary Electrophoresis Coupled with Contactless Conductivity Detection Using 18-Crown-6 Ether and Hexadecyltrimethylammonium Bromide as Complexing Reagents
AUTHORS:
Wujuan Chen, Fan Gao, Yi Zhang, Yan Zhang, Yi Li, Yating Zhang, Qingjiang Wang, Pingang He
KEYWORDS:
Capillary Electrophoresis, Contactless Conductivity Detection, Metal Ions, Food, Drinking Water
JOURNAL NAME:
American Journal of Analytical Chemistry,
Vol.7 No.11,
October
25,
2016
ABSTRACT: A simple, economical, and
sensitive capillary electrophoresis (CE) method integrated with capacitively
coupled contactless conductivity detection was developed for the determination
of metal ions such as K+, Na+, Mg2+, Sr2+,
Ca2+ in drinking water. 18-Crown-6 ether and
Hexadecyltrimethylammonium Bromide (CTAB) were employed as complexing reagents.
The effects of electrolyte additives, citric acid buffer solution, and other
separation conditions of CE were comprehensively investigated and carefully
optimized. The best results were obtained in a running buffer solution composed
of citric acid (12 mM), 18-crown-6 ether (0.2 mM), and CTAB (0.015 mM) at pH
3.5. Under these conditions, a complete separation of five metal ions was
successfully achieved in less than 12 min. The limits of detection for the
optimal procedure were determined to be in the range of 0.02 - 0.2
mg·L-1. The repeatability with respect to migration times and peak
areas, expressed as relative standard deviations, was better than 2.3% and
5.1%, respectively. Evaluation of the efficiency of the methodology indicated
that it was reliable for the determination of metal ions in six different
brands of drinking water samples.