High temperature direct probe for MS and its use for thermal decomposition monitoring

A high temperature direct probe has been constructed and coupled to a quadrupole mass spectrometer. Heating parameters are programmable, and the temperature range is up to 800 °C. The replaceable quartz and stainless-steel cylindrical sample holders fit into the axial bore (4 mm dia×12 mm) in the heated tip of the probe. The quantity of sample material required for the analysis is in the range of 0.1-30 mg. A 25 mm long thin-walled tube separates the hot tip from the water-cooled body of the probe. After the probe and the complete system had been tested with thermoanalytical standards, it was used to study the thermal reactions and decomposition of mineral samples: hyalophane feldspar and buddingtonite. Selected ion monitoring revealed ammonia in volatile and ionic (NH4+) form, H2O, N2 and CO2 in the samples.