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Indexed by:期刊论文

Date of Publication:2011-03-07

Journal:LAB ON A CHIP

Included Journals:SCIE、PubMed、Scopus

Volume:11

Issue:5

Page Number:969-973

ISSN No.:1473-0197

Abstract:A three-layer poly (methyl methacrylate) (PMMA) electrophoresis microchip integrated with Pt microelectrodes for contactless conductivity detection is presented. A 50 mu m-thick PMMA film is used as the insulating layer and placed between the channel plate (containing the microchannel) and the electrode plate (containing the microelectrode). The three-layer structure facilitates the achievement of a thin insulating layer, obviates the difficulty of integrating microelectrodes on a thin film, and does not compromise the integration of microchips. To overcome the thermal and chemical incompatibilities of polymers and photolithographic techniques, a modified lift-off process was developed to integrate Pt microelectrodes onto the PMMA substrate. A novel two-step bonding method was created to assemble the complete PMMA microchip. A low limit of detection of 1.25 mu g ml(-1) for Na(+) and high separation efficiency of 77 000 and 48 000 plates/m for Na(+) and K(+) were obtained when operating the detector at a low excitation frequency of 60 kHz.