ASTM D5837 Standard Test Method for Furanic Compounds in Electrical Insulating Liquids by High-Performance Liquid Chromatography (HPLC)
4. Summary of Test Method
4.1 Furanic compounds in electrical insulating liquids are extracted from a known volume of test specimen by means of a liquid/liquid extraction or solid-phase extraction. A direct injection of the oil also may be used.
4.2 A portion of the extract or an aliquot of the oil is introduced into an HPLC system equipped with a suitable analytical column and UV detector.
4.3 Furanic compounds in the test specimen are identified and quantified by comparison to standards of known concentration.
5. Significance and Use
5.1 Furanic compounds are generated by the degradation of cellulosic materials used in the solid insulation systems of electrical equipment.
5.2 Furanic compounds which are oil soluble to an appreciable degree will migrate into the insulating liquid.
5.3 High concentrations or unusual increases in the concentrations of furanic compounds in oil may indicate cellulose degradation from aging or incipient fault conditions. Testing for furanic compounds may be used to complement dissolved gas in oil analysis as performed in accordance with Test Method D3612.
6. Interferences
6.1 Materials used in the manufacture of the polypropylene tubes and polyethylene frits of some commercially prepared solid-phase extraction columns may interfere with the determination of furanic compounds, such as furfuryl alcohol and 5-hydroxymethyl-2-furaldehyde.
6.2 The use of acetone in any preparative or analytical step will cause accelerated sample decay and may interfere with the accurate determination of 5-hydroxymethyl-2- furaldehyde.
6.3 The use ofcellulosic filtering media may serve to adsorb furanic compounds yielding erroneous or unreproducible results, or both.
