Application of direct electrospray probe to analyze biological compounds and to couple to solid-phase microextraction to detect trace surfactants in aqueous solution

This work presents two novel direct electrospray probes (DEP) to generate a n electrospray without using a capillary and/or syringe pump. One of the DE Ps is simply a copper coil connecting to a high-voltage power supply. The s ample solution is deposited on the coil by a micropipet and the electrospra y is subsequently generated at the tip of the copper coil after high voltag e is applied to it. Another DEP is constructed by inserting two parallel op tical fibers through the copper coil. The two fibers extend one end of the copper coil by 1 cm. Electrospray is generated at the tip of the fibers thr ough the solution predeposited on the copper coil as the high voltage is ap plied on the copper coil. The ES mass spectra of myoglobin in liquid or sol id phases can be obtained using this DEP-MS. Coupling the DEP to a solid-ph ase microextraction fiber is extremely easy, and a trace amount tin ppb ran ge) of surfactants (Triton X-100) in the aqueous solution are selectively c oncentrated and detected.