The Thermo Scientific Delta Ray is a portable isotope ratio infrared spectrometer for on-site isotopic analysis. Its URI Connect interface extends the continuous measurement of isotope ratios and concentrations of CO2 in air to discrete samples, such as head space analysis or direct injection of small amounts of CO2. By simultaneously detecting 13C and 18O, it can measure both isotopologues and concentration in one step without destroying the sample. The URI Connect system handles samples containing as a little as 80 µg of CO2.