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Development of a new hybrid technique for rapid speciation analysis by directly interfacing a microfluidic chip‐based capillary electrophoresis system to atomic fluorescence spectrometry
Author(s) -
Li Feng,
Wang DongDong,
Yan XiuPing,
Lin JinMing,
Su RongGuo
Publication year - 2005
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200410382
Subject(s) - capillary electrophoresis , detection limit , chemistry , analyte , analytical chemistry (journal) , chromatography , effluent , chip , mercury (programming language) , capillary action , microfluidics , mass spectrometry , nanotechnology , materials science , electrical engineering , environmental engineering , computer science , engineering , composite material , programming language
This paper represents the first study on direct interfacing of microfluidic chip‐based capillary electrophoresis (chip‐CE) to a sensitive and selective detector, atomic fluorescence spectrometry (AFS) for rapid speciation analysis. A volatile species generation technique was employed to convert the analytes from the chip‐CE effluent into their respective volatile species. To facilitate the chip‐CE effluent delivery and to provide the necessary medium for subsequent volatile species generation, diluted HCl solution was introduced on the chip as the makeup solution. The chip‐CE‐AFS interface was constructed on the basis of a concentric “tube‐in‐tube” design for introducing a KBH 4 solution around the chip effluent as sheath flow and reductant for volatile species generation as well. The generated volatile species resulting from the reaction of the chip‐CE effluent and the sheath flow were separated from the reaction mixture in a gas‐liquid separator and swept into the AFS atomizer by an argon flow for AFS determination. Inorganic mercury (Hg(II)) and methylmercury (MeHg(I)) were chosen as the targets to demonstrate the performance of the present technique. Both mercury species were separated as their cysteine complexes within 64 s. The precision (relative standard deviation, RSD, n = 5) of migration time, peak area, and peak height for 2 mg·L −1 Hg(II) and 4 mg·L −1 MeHg(I) (as Hg) ranged from 0.7 to 0.9%, 2.1 to 2.9%, and 1.5 to 1.8%, respectively. The detection limit was 53 and 161 µg·L −1 (as Hg) for Hg(II) and MeHg(I), respectively. The recoveries of the spikes of mercury species in four locally collected water samples ranged from 92 to 108%.