KCS

Solid phase microextraction (SPME) and liquid phase microextraction (LPME) are commonly employed for headspace (HS) extraction, which is useful for the concentration of volatile materials in a complex matrix. Among LPME methods, single drop microextraction (SDME) is widely used for HS extraction to be off-line coupled with GC and LC. By forming a single acceptor drop at the tip of a capillary using a commercial capillary electrophoresis (CE) instrument, we showed that SDME can be easily in-lined coupled with CE to achieve high sample enrichments in a short time. However, it is difficult to hang a drop of very small volume to a separation capillary in the HS stably for long extraction. Recently this problem was solved by in-tube microextraction (ITME) using the liquid plug inside the capillary as an acceptor phase without hanging a drop. HS-ITME-CE was performed to enrich dichlorophenol in an aqueous solution. To promote the evaporation of the acidic dichlorophenols into the HS as neutral forms, the donor was acidified by adding HCl. To promote back extraction from the HS, a short acceptor plug of 400 mM borate buffer of pH 9.3 was used. The subsequent CE was carried out using a run buffer of 240 mM borate buffer of pH 9.2. With a 15-min extraction at 80°C, dichlorophenols were enriched about 300 times.