To achieve the selective solid-phase extraction of Pb2+ and Hg2+ ions by microfluidic chip

the surface modification of nano-silica was carried out by using 3-chloropropyltrimethoxysilane and 5-methylbenzotriazole. And then

an integrated solid-phase extraction chip with replaceable adsorbent was designed and prepared based on the modified nano-silica. The results show that

the agglomeration of the adsorbent is improved significantly. When pH=5

the adsorption rates of Pb2+ and Hg2+ are 99.1% and 98.9% respectively

while the adsorption rates of Cr3+ and Mn2+ are only 20.4% and 13.2% respectively. In addition

the absorption rates of Pb2+ and Hg2+ are both more than 97% even when mixing with the interference ions (K+

Na+ or Mn2+). When the sample flow rate is no more than 1.5 mL/min

the microfluidic chip adsorption rate of Pb2+ or Hg2+ are both more than 98%; when using the hydrochloric acid (0.5 mol / L) and 2% thiourea [CS (NH2)2(W/W)] as eluent

the elution rate of Pb2+ or Hg2+ is both more than 92% (the flow rate is between 0.2~0.3 mL/min). The successful preparation of selective solid-phase extraction chips for Pb2+ and Hg2+ contributes to the application and popularization of microfluidic technology in heavy metal pollution monitoring.