FIELD: chemistry.
SUBSTANCE: disclosed is a method of determining iron ions in lubricating compositions, involving the following steps: a) sampling the analyzed lubricating composition into a first container; b) placing said first container containing the analyzed sample on the magnet; c) adding to the second container: a first aqueous reactive composition (CR1) containing at least one extractant of trivalent iron ions and divalent iron from the oil phase into the aqueous phase; a second aqueous reactive composition (CR2) containing at least one ferric ion (Fe3+) to obtain divalent iron ions (Fe2+); a third reactive composition (CR3) containing at least one substance destabilizing the emulsion; and a fourth reactive composition (CR4) in an aqueous solution containing a complexing agent of divalent iron ions, characterized by a discolouration during complexation with divalent iron ions; and mixing thereof; d) performing photochemical measurement of optical density of mixture obtained at step c); e) collecting a plurality of drops of the lubricating composition contained in the first container held in a position on the magnet and adding said several drops to a second container containing a mixture of first, second, third and fourth reactive compositions obtained at step c); f) mixing the mixture obtained at step e); g) performing photochemical measurement of optical density of mixture obtained at step f). Also disclosed is a kit for implementing the above method.
EFFECT: determination of iron ions, trivalent iron ions and ferrous iron, obtained as a result of corrosion of metal parts in the engine – in lubricating compositions, which are extracted during use under engine cylinders.
22 cl, 2 dwg, 1 tbl, 1 ex
