High-performance liquid chromatography (HPLC) has been interfaced to a time-of-flight mass spectrometer. The interface is a continuous flow probe and ions are desorbed from the liquid matrix by energetic ion bombardment. Pulsed and delayed ion extraction from the source permits the use of broad ionization times, results in the production of analog signals in each time-of-flight cycle, and provides both energy and spatial focusing. A high-speed integrated transient recording system has been developed and is also reported. This instrument is the prototype for development of a high-speed, high-mass range LC detector with high duty cycle. Its performance is demonstrated for the separation of several mixtures of small peptides.