Isotope separation of U-233 by anion exchange chromatography based on the U(IV)-U(VI) exchange is studied. After long-distance migration, U-233 enrichment is observed at the rear band boundary. To examine the isotope effects of U-233, U-234, and U-238, three-isotope plots of local enrichment factors are constructed for the isotopes contained in sample fractions of the eluted uranium band. The results clearly show an anomalous mass dependence for U-233. We previously reported that the even-mass nuclides U-232, U-234, U-236, and U-238 show a regular mass-dependence in their isotope separation behaviors, while U-235 does nor fall on the same line. The isotope effects of the odd-mass nuclides U-233 and U-235 deviate from the linear mass dependence observed among the even-mass nuclides. The isotope effects observed in chemical exchange are shown to be closely related to the isotope shifts in the atomic spectra of uranium isotopes.