The heart of the DATU GCO system is the olfactometer block. Designed by Dr. Terry Acree and Robert M. Butts, the olfactometer block acts as a precise interface between the chromatographic column and the human subject assaying samples for odor-activity. Based on principles of the Venturi tube and precision machined out of nickel-plated pure aluminum block the DATU olfactometer takes high flow olfactometry air and wraps the low-mass flow of a capillary column in an envelope of purified air. This package of air and analyte is delivered to a human subject while maintaining both the linear velocity of the column and the chromatographic resolution of the analytes. The block can be programmed to run at temperatures up to 300ºC while the flow dynamics shield analytes from contact with the walls of the stainless steel sniff tube thus eliminating sample contamination and carryover. With the analytes delivered to the “sniffer” situated away from the heated block, the end-user is afforded both a comfortable position for sampling as well as easy sight lines and access to the data collection software.