The present disclosure is related to improved systems and methods for delivering samples for high-throughput mass spectrometric analysis to an atmospheric-pressure ionization source. In an exemplary embodiment, the system includes a solvent reservoir for storing a solvent solution, a first valve which is coupled to the solvent reservoir, first and second pumps for delivering solvent solution and which are coupled to the first valve and which the delivery flow rate of the first pump is greater than the delivery flow rate of the second pump, an injection system having a sample injector and an second valve which is coupled to the first valve and which is capable of being coupled to can be couple to an electrospray ionization source. In another embodiment, the system can also include an atmospheric-pressure ionization chamber, an atmospheric-pressure ionization sprayer and a nebulizer gas source and a voltage supply source. In yet another embodiment, the system may further include a puffer valve that is coupled to the nebulizer gas source and the atmospheric-pressure ionization sprayer and a gas puffer that is coupled to the puffer valve. A distal end of the gas puffer may be located within the atmospheric-pressure ionization chamber and aligned with the distal end of the atmospheric-pressure ionization sprayer and the puffer valve may control the delivery of the nebulizer gas to the atmospheric-pressure ionization sprayer and the gas puffer.