Capillary electrophoresis (CE) has been used for oligosaccharide analysis due to the high separation performance, but the concentration sensitivity is limited by the short optical pass length.To overcome the low sensitivity problem, we applied large-volume sample stacking with an electroosmotic flow (EOF) pump (LVSEP)1 to CE, which gave up to a 780-fold sensitivity enhancement without the loss of resolution.For further sensitivity improvement, in this study, LVSEP was combined with field-amplified sample iniection (FASI).