METHOD OF DETERMINING CONTENT OF DIESEL FUEL IN LUBRICATING OIL OF INTERNAL COMBUSTION ENGINE Russian patent published in 2009 - IPC G01N33/30 G01N30/02 

FIELD: chemistry.

SUBSTANCE: method of determining content of diesel fuel in lubricating oil of an internal combustion engine involves the following stages: preparing a mixture which contains an oil sample and C₅ hydrocarbon, such as C₅ alkane; injecting the mixture into the injector (11) of gas chromatograph (10); obtaining chromatographs of the sample; determination of the firs parametre M, which characterises peak area related to C₅ hydrocarbon, such as C₅ alkane, determination the second parametre C, which characterises area of at least one peak, related to a hydrocarbon, which characterises diesel fuel; and determination of content T of diesel fuel using formula (I): where a and b are constants, which define equation y=ax+b of a calibrating straight line of the ratio of the second to the first parametres as a function of content of diesel fuel.

EFFECT: increased accuracy and reliability of analysis.

8 cl, 3 dwg