METHOD OF DETERMINING ZINC DITHIOPHOSPHATES IN ENGINE OIL Russian patent published in 2015 - IPC G01N33/28 G01N30/14 

FIELD: chemistry.

SUBSTANCE: method includes preparing a 1% solution of engine oil in hexane for full extraction of zinc dithiophosphates from engine oil and purity of the obtained samples; adding the obtained solution to an extraction cartridge filled with hydroxylated silica gel in amount of not more than 2 ml of the 1% solution of the oil in hexane per 1 g sorbent; successively passing a hexane:acetone mixture taken in volume ratio of 9:1, respectively; passing an isopropanol:water:phosphoric acid:acetonitrile mixture, taken in ratio of 4:2:0.4:1, respectively. Each mixture is taken in amount of not less than 1.5 times the volume of the oil solution in hexane. An aliquot of the obtained solution is analysed by RP HPLC.

EFFECT: high accuracy and reliability of determination.

1 tbl, 7 dwg