Electrode-modified heavy metal ion microfluidic detection chip and preparation method

An electrode-modified heavy metal ion microfluidic detection chip, including a microfluidic module (1) and a three-electrode sensor (2), wherein:

• the microfluidic module (1) comprises a micro-channel (10), an inlet duct (12) and an outlet duct (13) are provided at opposite ends of the at least one micro-channel (10);
• the three-electrode sensor (2) comprises three all-solid-state planar electrodes provided on a card-shaped base plate (20), a working electrode (21), an auxiliary electrode (22) and a reference electrode (23);
• one end of the three-electrode sensor (2) is an interface area (24), contacts (240) at terminals of leads of the three all-solid-state planar electrodes are arranged in the interface area;
• a sensor slot (11) matching the three-electrode sensor (2) is provided at a bottom portion of the micro-channel (10) in the microfluidic module (1);
• when the three-electrode sensor (2) is inserted in the sensor slot (11), the three all-solid-state planar electrodes are communicated with the micro-channel (10), the three-electrode sensor (2) is assembled with the microfluidic module (1) by being inserted into the sensor slot (11), and is detachable;
• the interface area (24) is outside the sensor slot (11);
• the microfluidic module (1) is a 3D printed transparent flexible piece, the micro-channel (10), the inlet duct (12), the outlet duct (13), and the sensor slot (11) are integrally printed and formed on with the microfluidic module (1);
• the working electrode (21) is a bare carbon electrode, and a surface thereof is modified by porous nano-NiMn2O4;
• the auxiliary electrode (22) is an Ag electrode;
• and the reference electrode (23) is an Ag/AgCl electrode;
• wherein preparing the porous nano-NiMn2O4, specific steps of preparing the porous nano-NiMn2O4 include:
• dissolving MnCl2·6H2O 20 mmol/L, NiCl2·6H2O 40 mmol/L, Mn(NH2)2 120 mmol/L, and NH4F 0.1 g in ethanol 5 mL and deionized water 30 mL, stirring violently for 30 min;
• cooling the solution to room temperature, cleaning reaction products with distilled water for at least 5 times, and drying the same;
• and
• giving air annealing treatment to the reaction products at a tubular furnace at 2° C./min, preserving for 3 h at 350° C., so as to obtain porous nano-NiMn2O4 powder.