Finnigan MAT 252 isotope ratio mass spectrometer configured for H2, CO2, N2, O2, CO, and SO2. In the current configuration, the MAT 252 is coupled to the “in situ” laser-florination extraction line and is used for δ18O and δ17O analyses of silicates, δ18O by CF-TCEA, and δ2H measurements using conventional offline techniques. It is equipped with both a dual inlet multi-port as well as continuous flow GC-C-CF-IRMS system.