Interface for Coupling Capillary Electrophoresis to Inductively Coupled Plasma and On-Column Concentration Technique

摘要

Anew interface for coupling capillary electrophoresis (CE) to inductively coupled plasma (ICP) was developed. The interface was built outside and independent of the nebulizer and could be easily connected with a microconcentric nebulizer (MCN) as well as conventional pneumatic nebulizers. An on-column concentration technique was used to increase the sensitivity and to enhance the resolution of the system of capillary electrophoresis-inductively coupled plasma atomic emission spectrometry (CE-ICP-AES). By doing this, it was possible to analyze 1 μg/mL of total chromium (prepared with K↓(2)C↓(r2)O↓(7) and C↓(r)C1↓(3) and 1 μg/mL of copper consisting of Cu↑(2+) and Cu(EDTA)↑(2-) with good spectroscopic intensity and efficient separation. Detection limits of 18 elements for MCN-ICP-AFS coupled with CE were assessed by continuous sample introduction without applying high voltage and were found to be 1-4 times higher than those typically obtained by using MCN-ICP-AES for elemental analysis (without connection to the CE interface). When the on-column concentration technique was used, the sensitivities and separations were further improved by increasing the amount of sample. A simple electrolyte (0.05 M HNO↓(3)) and a large inner diameter capillary (150 μm) could also be used to attain efficient separation.