ASTM D5006 Test Method for Measurement of Fuel System Icing Inhibitors (Ether Type) in Aviation Fuels
4. Summary of Test Method
4.1 In order to determine the concentration of DiEGME in aviation fuel, a measured volume of fuel is extracted with a fixed ratio of water. The extraction procedure includes sufficient agitation and contacting time to ensure that equilibrium distributions are attained. If using an Analog Refractometer, place several drops of water extract on the measuring surface, point it towards a light source, and take a reading on the internal scale. The analog HB refractometer will display the actual percent volume of DiEGME on its scale. Users of a Brix refractometer will follow a similar procedure, but will have to convert the Brix reading into DiEGME percent volume. If the Brix refractometer is not automatically temperature compensated, then a temperature correction must first be applied to the Brix reading before converting it to percent DiEGME. If using a Digital Refractometer, place several drops of water extract in the sample well, press a button to initiate the reading, and the percent volume of DiEGME will be displayed on the LCD display. (Warning - Diethylene glycol monomethyl ether (DiEGME), slightly toxic material. This material caused slight embryo-fetal toxicity (delayed development) but no increase in birth defects in laboratory animals. Consult the suppliers' material safety data sheets.)
NOTE 1 - Isopropanol is not detected because of the similarity of isopropanol/water refractive indices, and the presence of iso propanol in fuel containing other additives results in lower than true values.
5. Significance and Use
5.1 DiEGME is miscible with water and can be readily extracted from the fuel by contact with water during shipping and in storage. Methods are therefore needed to check the additive content in the fuel to ensure proper additive concentration in the aircraft.
5.2 This test method is applicable to analyses performed in the field or in a laboratory.
