This invention provides an improved method for producing a novel interfacing capillary device that is less costly and more durable than existing sheathless devices. This simplified production method does not require sample dilution, etching, or precision hand tools, and is automated and reproducible.
The use of capillary electrophoresis–mass spectrometry (CE-MS) in the bioanalytical field has been limited due to the challenges associated with fabricating and operating the interface. Sheath and sheathless strategies have been developed for interfacing CE and MS. The top advantages for sheathless designs are the elimination of the need for a sheath liquid for electrical contact with the CE effluent to facilitate the electrospray process, and sheathless methods have been reported to be a 10 times more sensitive. While there are functional sheathless CE-ESI-MS systems available, improvements in producing components of the interface could lead to advancing the state of the art towards the production of more robust and less costly systems.
This invention is useful in the bioanalytical, pharmaceuticals, environmental and forensic fields where CE-MS is employed to separate targeted analytes present in extremely low concentrations. The invention is specifically useful for fabricating improved devices for interfaces for CE-MS.
This invention employs an automated CO2 laser to introduce holes into the capillary wall for voltage application. The holes are then coated with cellulose acetate to create a semi-permeable membrane for the exchange of electrons and small ions between the capillary and the buffer reservoir to generate electrospray prior to electrophoresis.
The invention provides a simplified method for producing a low-cost sheathless interface for CE-MS. It is also automated and easily reproducible.
Unlike existing methods for producing sheathless interfaces for CE-MS, this invention enables the high-throughput production of a low-cost sheathless interface for CE-MS that is more durable than existing alternatives. Also, no sample dilution is required.