Microfluidic chips coupled with electrospray ionization (ESI) mass spectrometry (MS) is an analytical platform with high detection throughputs and low sample consumptions. However, its applications in probing real samples are limited by the absence of reliable on-chip sample pretreatments, which are indispensable due to both the low contents of analytes and the poor salt tolerance of ESI MS. Herein, we propose an automated extraction and ESI chip (AEEC), consisting of a solid phase extraction (SPE) zone, seven on-chip pneumatic micro-valves, a monolithic ESI nozzle, and other components, to im...
