  The interaction cross sections of $^{22,23}$O nuclei at 900 MeV/nucleon have
been measured recently by Kanungo {\it et al.}. We show that the odd-even
staggering parameter of interaction cross sections deduced from these new data
agrees well with the theoretical systematics expected for the neutron
separation energy of $S_n$=2.74$\pm$0.120 MeV for $^{23}$O. We also discuss
briefly the energy dependence of the staggering parameter.
