title: Elimination of suction effect in interfacing microchip electrophoresis with inductively coupled plasma mass spectrometry using porous monolithic plugs.
abstract: A suction-free interfacing method was developed for microchip electrophoresis hyphenated with inductively coupled plasma mass spectrometry (MCE-ICP-MS). The hyphenated system was composed of a microchip, a demountable capillary microflow nebulizer (d-CMN) combined with a heated single pass spray chamber, a negative pressure sampling device, a high voltage power supply, a syringe pump and an ICP-MS. To eliminate the nebulizer suction generated by the pneumatic nebulizer and to ensure that the makeup solution flowed into the nebulizer, two porous polymer plugs were fabricated in the microchip. As a result, reasonably true electropherograms were obtained when compared to the CE separation performed in the traditional MCE-ICP-MS mode without porous polymer plugs. Electrophoretic separation of I(-) and IO(3)(-) was achieved within 25 s in a microchip with an effective separation length of only 15 mm at an electric field of 857 V cm(-1) using 10 mmol L(-1) borate (pH 9.2) as the running buffer. A resolution of 1.3 was obtained and the absolute detection limits for I(-) and IO(3)(-) were 0.12 and 0.13 fg, respectively. The precisions (RSD, n = 10) of the migration time and peak height for I(-) and IO(3)(-) were in the range of 1.1-1.6% and 2.5-2.8%, respectively. Two table salt samples were analyzed by an external calibration method. The iodate contents were in accordance with their labeled values. The recoveries of I(-) and IO(3)(-) in the table salt samples were in the range of 92-105%.
authors.affiliation: Institute of Microanalytical Systems, Department of Chemistry, Zhejiang University, Hangzhou, 310027, China.
authors.forename: Heyong
authors.initials: H
authors.lastname: Cheng
authors.forename: Jinhua
authors.initials: J
authors.lastname: Liu
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Yin
authors.forename: Hong
authors.initials: H
authors.lastname: Shen
authors.forename: Zigang
authors.initials: Z
authors.lastname: Xu
mesh_terms: D046209:Electrophoresis, Microchip / Q000379:methods*; D013058:Mass Spectrometry / Q000379:methods*