<b>Use of weak ion association in the separation of inorganic anions by capillary electrophoresis with specific application to simultaneous-trace determination of bromate and iodate in drinking water</b>

Abstract

In this work weak ion association was used to effect selectivity and detection of inorganic anions with environmental or health significance by capillary electropheresis, CE. Tetrabutylammonium ion was used as a pairing anion to separate mixtures containing closely or co-migrating inorganic anions at pHs 3.8 and pH 7. Despite taking a longer analysis time, better resolution is achieved at pH 7 than 3.8. Trace level of bromate and iodate present in drinking water were determined after online pre-concentration by field enhanced sample injection (FESI) technique. Consequently an internal standard (SCN-) was employed, which entailed the use of tetrabutylammonium ion as a pairing cation to resolve the internal standard from a co-migrating broad peak. The LODs (S/N = 3) were 7.8 x 10-10 M (10 ppb) and 1.2 x 10-9 M (0.21 ppb) for bromate and iodate, respectively. The method was subsequently used to determine bromate and iodate levels in drinking water.

Sensitive Determination of Bromate in Water Samples by Capillary Electrophoresis Coupled with Electromembrane Extraction

“…CE coupled with UV detection (CE-UV) (Fukushi et al 2009;Marak et al 2012;Mbuna et al 2008;Takayanag et al 2006;Gries et al 2008), MS (CE-MS) (Chen et al 2007;Zhang et al 2011), chemically modified electrode electrochemical detection (CE-CME-ED) (Liu et al 2011;Pang et al 2012), and CD (CE-CD) (Bodor et al 2002;Kvasnicka et al 2005) have been applied for the determination of bromate. Other techniques, such as isotachophoresis (ITP) (Bodor et al 2002;Fukushi et al 2009;Kvasnicka et al 2005;Marak et al 2012), pressureassisted electrokinetic injection (PAEI) (Zhang et al 2011), and field-enhanced sample injection (FASI) (Mbuna et al 2008;Takayanag et al 2006) have been used as the online concentration procedures to fulfill the analysis of trace bromate. Capacitively coupled contactless conductivity detection (C 4 D) introduced by Fracassi da Silva and Zemann independently in 1998 (Fracassi da Silva and do Lago 1998;Zemann et al 1998) has been considered as a universal detection technique for CE because of its various advantages including the elimination of electrode surface fouling, effective isolation from high separation voltages, simplified detector design, and electrode alignment (Kuban and Hauser 2009).…”