화학공학소재연구정보센터
Electrophoresis, Vol.39, No.16, 2152-2159, 2018
Electromembrane extraction and capillary electrophoresis with capacitively coupled contactless conductivity detection: Multi-extraction capabilities to analyses trace metals from saline samples
Simultaneous electromembrane extraction (EME) of six trace metal cations (Cu2+, Zn2+, Co2+, Ni2+, Pb2+, Cd2+) from saline samples was investigated. CE with capacitively coupled contactless conductivity detection ((CD)-D-4) was used to determine the metals in acceptor solutions due to its excellent compatibility with theminute volumes of acceptor solutions. Bis(2-ethylhexyl)phosphate (DEHPA) was selected as a suitable nonselective modifier for EME transport of target metal cations. Both, the individual effect of each major inorganic cation (Na+, K+, Ca2+, Mg2+) and their synergistic effect on EME of the trace metal cations were evaluated. In both cases, a decrease in extraction efficiency was observed when major inorganic cations were present in the sample. This effect was more significant for Ca2+ and Mg2+. The system was optimized for simultaneous extractions of the six target metals from saline samples (50mM Na+, 5mM Mg2+, 1mM K+, and 1mM Ca2+) and following EME conditions were applied. Organic phase consisted of 1-nonanol containing 1%(v/v) DEHPA, acceptor solution was 1M acetic acid (HAc) and sample pH was adjusted to 5. Sample was stirred at 750 rpm and EMEs were carried out at extraction potential of 10V for 20min. The method presented a repeatability between 8 and 21.8% (n=5), good linearity in 0.5-10M concentration range (R-2=0.987-0.999) and LOD better than 2.6nM. Applicability of the EME-CE-(CD)-D-4 method to the analyses of metal cations in drinking water, seawater, and urine samples was also demonstrated.