An Improved ASTM D3612 TOGAS System

ASTM D-3612 is a GC method to extract and determine Hydrogen, Oxygen, Nitrogen, Methane, Carbon Monoxide and C2-C3 in hydrocarbon-based transformer oils. Three procedures have been described based on a gas chromatograph with TCD, Methanizer and FID. Two improvements have been made by employing a Barrier Ionization Discharge (BID) Detector in place of the TCD: (a) Hydrogen and Methane Detection Levels have been lowered from 10ppm to 100ppb and (b) Propylene has been incorporated in the analysis.Two PLOT columns in serials and a 4-port sampling valve direct the gas components to either BID or FID. H₂, O₂, N₂, CH₄, CO are separated and detected by BID; CO₂, C₂H₂, C₂H₄, C₂H₆ and C₃H₆ detected by FID. CO₂ passes through a Methanizer and is reduced to CH₄, which, is combustible and analyzed by FID.