Determination Of H20 And D20 Contents In Rhyolitic Glasses

Five distinct analytical techniques were compared for the quantification of the H2O (0.1-7.4wt%) and D20 (up to 5.5 wt% D20)contents in rhyolitic glasses. The hydrogen concentration in obsidians was measured using nuclear reaction analysis and converted into H2O concentration. The bulk water content of synthesised glasses was determined using thermal extraction in conjunction with Karl-Fischer titration. Unextracted H2O was measured by infrared spectroscopy after remelting the KFT products at high pressure. These well characterised glasses were subsequently used to calibrate secondary ion mass spectrometry, infrared and evolved gas analysis.