Piezoelectric charged droplet source

An ion source for preparing gas phase analyte ions from a liquid sample, containing chemical species in a solvent carrier liquid or both, said source comprising;

• a) a piezoelectric element with an axial bore, positioned along the droplet production axis, having an internal end and an external end, wherein said piezoelectric element is capable of generating a pulsed pressure wave within the axial bore upon application of a pulsed electric potential to the piezoelectric element;
• b) a dispenser element positioned within the axial bore of said piezoelectric element, wherein the dispenser element extends a selected distance past the external end of the axial bore and terminates at a dispensing end with a small aperture opening, wherein the dispenser element extends a selected distance past the internal end of the axial bore and terminates at an inlet end for introducing liquid sample and wherein said pulsed pressure wave is conveyed through said dispenser element and generates electrically charged droplets of the liquid sample that exit the dispensing end at a selected droplet exit time and travel along a droplet production axis;
• c) an electrode in contact with said liquid sample, which is capable of holding said liquid sample at a selected electric potential;
• d) a shield element positioned between said electrode and said piezoelectric element for substantially preventing the electric field, electromagnetic field or both generated from said electrode from interacting with said piezoelectric element;
• and
• e) a piezoelectric controller operationally connected to said piezoelectric element capable of adjusting the onset time, frequency, amplitude, rise time, fall time and duration of the pulsed electric potential applied to the piezoelectric element which selects the onset time, frequency, amplitude, rise time, fall time and duration of the pulsed pressure wave within the axial bore;
• and
• f) a field desorption region of selected length positioned along said droplet production axis at a selected distance downstream from said piezoelectric element, with respect to the flow of bath, for receiving the flow of bath gas and electrically charged droplets, wherein at least partial evaporation of solvent, carrier liquid or both from the droplets generates gas phase analyte ions and wherein the electrically charged droplets, analyte ions or both remain in the field desorption region for a selected residence time.

A device for determining the identity, concentration or both of chemical species in a liquid sample containing the chemical species in a solvent, carrier liquid or both, said device comprising:

• a) a piezoelectric element with an axial bore, positioned along the droplet production axis, having an internal end and an external end, wherein said piezoelectric element is capable of generating a pulsed pressure wave within the axial bore upon application of a pulsed electric potential to the piezoelectric element;
• b) a dispenser element positioned within the axial bore of said piezoelectric element, wherein the dispenser element extends a selected distance past the external end of the axial bore and terminates at a dispensing end with a small aperture opening, wherein the dispenser element extends a selected distance past the internal end of the axial bore and terminates at an inlet end for introducing liquid sample and wherein said pulsed pressure wave is conveyed through said dispenser element and generates electrically charged droplets of the liquid sample that exit the dispensing end at a selected droplet exit time and travel along a droplet production axis;
• c) an electrode in contact with said liquid sample, which is capable of holding said liquid sample at a selected electric potential;
• d) a shield element positioned between said electrode and said piezoelectric element for substantially preventing the electric field, electromagnetic field or both generated from said electrode from interacting with said piezoelectric element;
• and
• e) a piezoelectric controller operationally connected to said piezoelectric element capable of adjusting the onset time, frequency, amplitude, rise time, fall time and duration of the pulsed electric potential applied to the piezoelectric element which selects the onset time, frequency, amplitude, rise time, fall time and duration of the pulsed pressure wave within the axial bore;
• f) a field desorption region of selected length positioned along said droplet production axis at a selected distance downstream from said piezoelectric element, with respect to the flow of bath, for receiving the flow of bath gas and electrically charged droplets, wherein at least partial evaporation of solvent, carrier liquid or both from the droplets generates gas phase analyte ions and wherein the electrically charged droplets, analyte ions or both remain in the field desorption region for a selected residence time;
• and
• g) a charged particle analyzer operationally connected to said field desorption region, for analyzing said gas phase analyte ions.