Back Cover: Combination of large‐volume sample stacking with an electroosmotic flow pump with field‐amplified sample injection on cross‐channel chips

Electrophoresis 2017, 38 , 2075–2080. DOI: 10.1002/elps.201700155 The back cover picture shows a combination of large‐volume sample stacking with an electroosmotic flow pump (LVSEP) with field‐amplified sample injection (FASI) on a cross‐channel microchip with a large sample reservoir for highly sensitive analyses. By applying reversed‐polarity voltages on a cross‐channel chip, anionic analytes injected throughout a microchannel were first concentrated on the basis of LVSEP, followed by the electrokinetic stacking injection of the analytes from a sample reservoir by the FASI mechanism. Due to the dual preconcentration effects, amino acids were well enriched to give intense and sharp peaks with the preconcentration factors of 2400∼2970.