A sheathless poly(methyl methacrylate) chip-CE/MS interface fabricated using a wire-assisted epoxy-fixing method

Using a wire‐assisted epoxy‐fixing method, a sheathless CE/MS interface on a poly‐(methyl methacrylate) (PMMA) CE chip has been developed. The sheathless chip‐CE/MS interface utilized a tapered fused‐silica tip and the electrical connection was achieved through a layered coating of conductive rubber. The wire‐assisted method provided facile alignment of channels between the PMMA CE chip and an external capillary sprayer without the need for micromachining. Because the wire was in the channel during fixing, the risk of channel blockage by the epoxy was avoided. This chip CE device has minimal dead volume because the interstitial spaces were filled by a fast‐fixing epoxy resin. The performance of the chip‐CE‐ESI‐MS device was demonstrated with the analysis of peptide mixtures.