The systems and methods herein involve the use of an automated, high-throughput system that utilizes pressure to transfer a fluid medium containing an analyte. In preferred embodiments, the sample is delivered to an analytical device. The sample can comprise one or more analytes, e.g., solvents, solutes, or particles, including rare cells. The systems are designed to minimize contact with potentially hazardous, fragile, or valuable samples. The systems allow for the dilution, mixing, and introduction of the fluid medium to an analytical device, followed by possible further analysis or sample manipulation. The systems and methods herein allow for partial or substantially complete depletion of a sample container to avoid wasting rare analytes or prevent retention of desired material in a first container.