12. Determination of other chemical elements

12.1 Total chlorine content (Cl–)

Among other methods, the total chlorine content (Cl ^– ) of hydraulic fluids is determined by "coulometry-argentiometry", using a non-standardized method developed specifically for this type of product by the EADS Joint Research Centre. The hydraulic fluid is diluted 50/50 in acetone. The test sample, between 25 and 50 µL, is injected via a microsyringe into an oven heated to 1,050°C for mineralization, where it burns under a current of oxygen.

The chlorine, converted into chloride ions, is carried by the oxygen stream and bubbles into a microcell containing an electrolyte, an isopropanol-based solution of composition :

• isopropanol:...