Patent ID: 7315021

Claim:
A charged droplet sprayer apparatus comprising: a) a sample delivery tube comprising en entrance end and an exit end, for transporting a liquid sample downstream from said entrance end to said exit end; b) a guide tube through which said sample delivery tube extends, said guide tube allowing said sample delivery tube to move freely along the axis of said guide tube while essentially preventing displacement of said sample delivery tube in any direction orthogonal to said guide tube axis; c) a conduit for gas flow, said conduit comprising the annular space between at least a portion of said sample delivery tube proximal to said exit end, and a gas flow tube surrounding and essentially coaxial with said portion, the exit opening of said gas flow tube being proximal to said exit end of said sample delivery tube; d) means for flowing gas through said gas flow conduit; e) means for forming an electric field at said exit end; and f) means for adjusting the axial position of said sample delivery tube within said guide tube, wherein the relative axial positions of said exit end of said sample delivery tube and said exit opening of said gas flow tube is adjusted.