用于Pb2+、Hg2+离子选择性固相萃取的微流控芯片

摘要

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 solidphase extraction chips for Pb2+ and Hg2+ contributes to the application and popularization of microfluidic technologyin heavy metal pollution monitoring.%为实现微流控芯片对重金属Pb2+、Hg2+离子的选择性固相萃取,首先采用3-氯丙基三甲氧基硅烷和5-甲基苯并三氮唑对纳米二氧化硅进行硅烷偶联改性,随后以改性纳米二氧化硅为基础,设计并制备了可更换吸附剂的一体化填充式固相萃取芯片.测试结果表明:改性后不仅吸附剂的团聚现象得到明显改善,且当pH=5时,对Pb2+的吸附率可达99.1％,对Hg2+的吸附率可达98.9％,而对Cr3+的吸附率为20.4％,对Mn2+的吸附率仅为13.2％.即使样品中混有干扰离子(K+、Na+或Mn2+)时,对Pb2+、Hg2+离子的吸附率仍均可达97％以上.当进样流速≤1.5 mL/min时,微流控芯片对pb2+或Hg2+的吸附率可达98％以上;以0.5 mol/L的盐酸和2％的硫代尿素为洗脱液,控制流速在0.2～0.3 mL/min范围内时,芯片对Pb2+或Hg2+的洗脱率均达到92％以上.用于pb2+、Hg2+离子的选择性固相萃取芯片的成功制备,有助于微流控技术在重金属污染监测领域的应用和推广.