We describe a 100%-efficient moving-wire interface (MWI) for online coupling of high-performance liquid chromatography (HPLC) that transmits 100% of the carbon in nonvolatile analytes to a CO(2)-gas-accepting ion source. This interface accepts a flow of analyte in solvent, evaporates the solvent, combusts the remaining analyte, and directs the combustion products to the instrument of choice. Effluent is transferred to a periodically indented wire by a coherent jet to increase efficiency and maintain peak resolution. The combustion oven is plumbed such that gaseous combustion products are completely directed to an exit capillary, avoiding the loss of combustion products to the atmosphere. This system achieves almost-complete transfer of the analyte at HPLC flow rates up to 125 μL/min at a wire speed of 6 cm/s. This represents a 30× increase in efficiency and an 8× increase in maximum wire loading, compared to the spray transfer technique used in earlier MWIs.