A gas-accepting microwave ion source built at Chalk River Laboratories, Canada has been tested and further developed at NOSAMS. The source uses microwave energy and a continuously flowing stream of gas to sustain a stable plasma from which positive ions are extracted. With a CO2 gas flow of about 230µL/min the ion source yields 12C+ beams of up to 1 mA. After conversion to negative carbon ions by passage through a magnesium vapor charge exchange canal about 0.08 mA 12C- beams are obtained.A number of experiments performed at NOSAMS have shown that the source is able to accept a wide range of continuous flow systems. Here, we describe a programmed-temperature combustion system which is interfaced to the microwave ion source via a water-removal system, open-split device, and flow-limiting capillary. The combustion system is comprised of two reactors of which the first is temperature controlled within a range between room temperature and 900°C. This reactor also contains a sample chamber with a usable volume of at least 5 cm3. The second reactor is operated at a constant temperature of about 850°C and is used for the oxidation of all carbon produced by sample heating. Argon is used as a carrier gas to transport effluents to the ion source. First results of operation will be presented and discussed.