Method for feedback controlled electrospray

A method for controlling an electrospray of fluid emitted by an electrospray nozzle communicating with a source of electrical potential and having a nozzle tip which is displaced from a counterelectrode or mass spectrometer inlet, to achieve and maintain a predetermined electrospray pattern, which comprises

• a) focusing light from a source of light to intersect one or more of the liquid cone, jet and plume of the fluid emitted by the electrospray nozzle,
• b) detecting scattered light patterns, transmitted light patterns or both, passing through, reflected by or emitted from said fluid emitted by said electrospray nozzle as a result of said intersection of said light with said one or more of said liquid cone, jet and plume, with one or more photo detectors and generating analog electronic signals containing sufficient information to represent the detected scattered light patterns, transmitted light patterns, or both,
• c) converting said analog electronic signals into a digital electronic patterns,
• d) interpreting said digital electronic patterns with a first computer or microprocessor system, and transmitting said interpreted patterns to a second computer or microprocessor,
• e) comparing said interpreted patterns to a reference pattern, which is defined by the predetermined electrospray pattern, with a second computer or microprocessor, and generating a control signal in response to said comparison, and transmitting said control signal to a controller, which, in accordance with said control signal,
• f) displaces said nozzle or said counterelectrode, or both, to adjust the distance between said electrospray nozzle and said counterelectrode or changes the voltage applied to said nozzle with respect to said counter electrode or mass spectrometer inlet if and to the extent necessary to adjust the morphology of said electrospray to result in an interpreted pattern towards that of the predetermined electrospray pattern.