Integrated polysaccharides via amidation for sensitive electrochemical detection of heavy metal ions

In this work, polysaccharide sodium alginate(SA) and chitosan(CS) were aminated and crosslinked to form honeycomb structure with hollow structure sodium alginate-chitosan complex (SA-CS). The honeycomb structure with hollow structure generated by crosslinked polysaccharides exposed the polar functional groups of SA and CS compared with individual SA and CS, resulting in a significant increase in the hydrophilicity of SA-CS. Excessive intake and accumulation of Cu 2+ will cause health hazards to the human body, animals and plants, and some diseases will appear. Therefore, we need to develop suitable detection methods. We modified the integrated polysaccharide complex SA-CS on the surface of the glassy carbon electrode (GCE), and optimized the experimental conditions of SA-CS/GCE for the detection of heavy metal copper ions by differential pulse voltammetry (DPV). Since the cross-linked SA-CS increases the recognition sites for Cu 2+ while exposing functional groups, it has high selective coordination ability for SA-CS/GCE to Cu 2+ , and can realize the selective detection of Cu 2+ . There is a good linear relationship between a series of different concentrations of Cu 2+ and peak current, the linear range is 1–100 μmol L −1 , the obtained standard curve is i pc (μA) = 0.08172X (μmol L −1 ) + 2.201, R 2  = 0.9919, the detection limit is 0.9545 μmol L −1 when the signal-to-noise ratio is at 3. Therefore, the SA-CS polysaccharide complex is expected to be constructed as a non-toxic, non-polluting, electrochemical sensor that selectively detects heavy metal copper ions in water.