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An effective method for isotope ratio analysis of individual particles containing uranium in safeguard swipe samples was developed by using a fission track (FT) technique combined with thermal ionization mass spectrometry (TIMS). The particles in the sample were directly recovered onto a polycarbonate membrane filter, which was set in a filtration system. After the particle recovery, the filter was dissolved to form a non coated FT detector film containing the particles. Individual particles containing uranium were then identified by the observation of fission tracks created by thermal neutron irradiation. By combining the FT technique with TIMS, isotope ratios of uranium for individual particles in the swipe sample prepared from a uranium standard reference material could be effectively determined.

Titanium isotopes of Ti (III) or Ti (IV) were fractionated by liquid‐liquid extraction system using dicyclohexano‐18‐crown‐6. The nuclear size and shape effect and the nuclear spin effect resulted in the breakdowns of the linear dependency of the enrichment factors to the mass difference. The nuclear mass effect, the nuclear size and shape effect and the nuclear spin effect were calculated by the isotope pair evaluation method. The nuclear mass effects were 0.000634 for 48Ti‐46Ti (III) and 0.000559 for 48Ti‐46Ti (IV), where the total enrichment factor were 0.000989 and −0.000166, respectively. The nuclear size and shape effects were 0.000356 for 48Ti‐46Ti (III) and −0.000725 for 48Ti‐46Ti (IV). The nuclear spin effects were 0.000180 for 47Ti (III), 0.000369 for 49Ti (III), −0.000303 for 47Ti (IV) and −0.000526 for 49Ti (IV). The ratio of chemical effect given by the field shift of 3d‐orbital to that of 4s‐orbital was −1.54, which had same direction and quantity with the field shift ratio of 3d‐orbital to 4s‐orbital in Ti I in atomic spectra. This showed that the nuclear size and shape effect on the chemical isotope effect directly reflected the field shifts of Ti I. The nuclear spin effect was the function of the number of the hyperfine splitting vibrational energy levels and the coordination number. This effect was found when the coordination numbers differ nonstoichiometrically between the aqueous phase and the organic phase.