Portable anti-fouling electrochemical sensor for soil heavy metal ions detection based on the screen-printed carbon electrode modified with silica isoporous membrane

Heavy metal ions (HMIs) pollutant is a serious environmental problem and the on-site supervision exhibits increasing urgency. Silica isoporous membrane (SIM) has the characteristic of anti-fouling while screen-printed carbon electrode (SPCE) is a universal detection platform that is feasible to commercialize. According to the principle of electrochemically assisted self-assembly (EASA), SIM was prepared on the SPCE surface for the first time. A highly ordered mesoporous silica membrane was obtained when a cathodic current was applied to the electro-activated SPCE. The developed SIM/SPCE was used for detecting the soil Cd2+, Pb2+, Cu2+, and Hg2+ by the square wave anodic stripping voltammetry (SWASV). Owing to the large specific surface area of SIM, the SIM/SPCE responded HMIs with enhanced SWASV signals. The detection limits of Cd2+, Pb2+, Cu2+, and Hg2+ were 9.3, 1.1, 16.2, and 1.4 nM, respectively. More importantly, the SIM/SPCE had a fine anti-fouling capability arising from steric exclusion and selective permeation. The soil samples were only diluted with buffer and the analytical performance was not decreased, suggesting a free of tedious sample pretreatments. Additionally, the universal use of SPCE endows the SIM/SPCE with more compatibility for instrumentation, thus driving an attractive application in the field of portable detection.