[en] A method is developed for determination of mass number of possible superheavy nuclides with the help of electromagnetic mass separator. The first particularity of the method is mass separation of a preparate under study as two-charge ions in order to discriminate molecular compounds of thorium and uranium interfering to observe superheavy nuclides. The second property is using of the bremsstrahlung obtained from the 16 MeV electrons which garantees detecting of nass separated superheavy nuclides through their induced fission. The sensitivity of the method is 6 x 10 ^-12 g of possible superheavy nuclides per 1 g of the preparate under study or (taking into account preliminary chemical enrichment) 10^-14 g of superheavy nuclides per 1 g of natural sample