Abstract: An Electrospray probe which includes a replaceable or disposable micron size diameter Electrospray tip used for low flow rate Electrospray has been developed. The Electrospray probe assembly combines the use of a low pressure gas and electric fields to initiate and sustain the Electrospray process at low liquid flow rates. The operational flow rates of this probe range from below 25 nL/min to over 1 &mgr;L/min, with total sample volume loaded ranging from less than 1 &mgr;L to over 20 &mgr;L. The Electrospray probe assembly includes axial and radial adjustment of the Electrospray tip position relative to the sampling orifice into vacuum and that tip position can be locked in place. The replaceable microtip can be safely removed from the Electrospray (ES) chamber without turning off high voltage within the ES chamber. Telescoping support ways have been included to prevent ES tip damage by guiding the Electrospray probe tip during removal from and insertion into the ES chamber.

Abstract: An Electrospray probe which includes a replaceable or disposable micron size diameter Electrospray tip used for low flow rate Electrospray has been developed. The Electrospray probe assembly combines the use of a low pressure gas and electric fields to initiate and sustain the Electrospray process at low liquid flow rates. The operational flow rates of this probe range from below 25 nL/min to over 1 .mu.L/min, with total sample volume loaded ranging from less than 1 .mu.L to over 20 .mu.L. The Electrospray probe assembly includes axial and radial adjustment of the Electrospray tip position relative to the sampling orifice into vacuum and that tip position can be locked in place. The replaceable microtip can be safely removed from the Electrospray (ES) chamber without turning off high voltage within the ES chamber. Telescoping support ways have been included to prevent ES tip damage by guiding the Electrospray probe tip during removal from and insertion into the ES chamber.

Abstract: A polynucleotide synthesizer comprises a supply mechanism for supplying a) liquid reactants for synthesizing peptides or polynucleotides, b) liquid reagents that assist in the synthesis, and c) a wash liquid; a reactor column; a connecting device for fluidly connecting the supply mechanism with the column; apparatus for positively displacing with gas pressure, liquid reactants and reagents, and wash liquid from the supply mechanism into the connecting device; and a controller connected to the column for allowing liquid to flow under the force of the gas pressure and at a controlled rate, into a temporary storage chamber and for thereafter emptying the chamber.