Systems and methods for ionization

A system for analyzing a sample comprising:

• an electrospray source configured to
• direct, at a junction, a first portion of a flow from a chromatographic device via a waste outlet to a pressurized waste reservoir;
• direct, at the junction, a second portion of the flow to an electrospray ionization outlet to form a spray, a flow rate of the second portion of the liquid flow is substantially determined by a pressure of the pressurized waste reservoir, wherein the electrospray ionization outlet includes a platinum wire threaded through the junction and at least one electrospray emitter, the platinum wire to provide a voltage to the second portion of the flow at the at least one electrospray emitter;
• and
• charge and desolvate the spray to form ions of the components of the sample;
• a mass resolving device configured to:
• receive the ions;
• and
• characterize the mass-to-charge ratio of the ions;
• and
• a controller configured to:
• adjusting the pressure within the pressurized waste reservoir to control the flow
• rate of the second portion to the electrospray ionization outlet.